1. A power network system comprising a plurality of power cells each comprising a power router for asynchronous connection to a power grid, wherein the power router comprises: a DC bus maintained at a predetermined rated voltage; a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and control means for controlling the plurality of input/output end parts, at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts, some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends, each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources, some of the plurality of input/output end parts included in the second power router are used as a plurality of power receiving ends, each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends, the power network system comprises a power adjustment apparatus connected to the first and second power routers through a communication network, the power adjustment apparatus comprises power adjustment means for adjusting the supply power according to a power request value 97 requested in each of the plurality of power receiving ends, and the power adjustment means: acquires, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining a power transmitting end for which an adjustment of the supply power to be supplied to each of the plurality of power receiving ends should be prioritized; and determines a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and the priority defined in the power supply priority information.

2. The power network system according to Claim 1, wherein the power adjustment means adjusts the supply power in the determined power transmitting end so as to bring a value of the received power in each of the power receiving ends closer to the power request value.

3. The power network system according to Claim 1 or 2, wherein the power adjustment means: adjusts, for each of the plurality of power receiving ends, the supply power of the power transmitting end having the highest priority, which is determined based on the received power information and the power supply priority information; and determines, after the adjustment, the power transmitting end having a next highest priority as the power transmitting end for which the supply power is adjusted based on the received power information and the power supply priority information.

4. The power network system according to any one of Claims 1 to 3, wherein the received power information further includes attribute 98 information of a supply source that supplies the supply power for each of the plurality of power transmitting ends, in the power supply priority information, a priority of the attribute information is defined as a priority for determining the power transmitting end for which the adjustment should be prioritized for each of the plurality of power receiving ends, and the power adjustment means: refers to the power supply priority information and specifies the attribute information corresponding to a predetermined priority; and refers to the received power information and determines the power transmitting end corresponding to the specified attribute information.

5. The power network system according to Claim 4, wherein the attribute information includes, for each of the plurality of power transmitting ends, a plurality of attribute types and attribute values corresponding to the respective attribute types, the power supply priority information includes information in a case where different priorities of the attribute types or different priorities of the attribute values are defined among the plurality of power receiving ends.

6. The power network system according to any one of Claims 1 to 5, wherein the power adjustment means: calculates, for each of the plurality of power receiving ends, a difference between a current received power value and the power request value; selects a priority to be processed in a descending order from the highest priority to the lowest priority based on the power supply priority information; performs a determination process every time the priority to be processed is selected until the difference is cancelled out; and adjusts the supply power in each of the plurality of power transmitting ends based on an adjustment value of the supply power 99 determined by the determination process, and the determination process comprises: specifying the power transmitting end corresponding to the priority to be processed among the power transmitting ends included in the received power information for each of the plurality of power receiving ends; specifying a value of the supply power supplied from the specified power transmitting end included in the current received power value based on the received power information and setting this specified supply power value as an increase/decrease request value for the specified power transmitting end; calculating a total increase/decrease request value by summing up the increase/decrease request value sets for each of the plurality of power transmitting ends; determining whether or not the total value of the current supply power value in each of the plurality of power transmitting ends and the total increase/decrease request value is within a predetermined threshold range; determining, when the total value is determined to be within the threshold range, the increase/decrease request value set for each of the plurality of power transmitting ends as the adjustment value of the supply power for the power transmitting end for which the determination is made and correcting, when the total value is determined to be outside the threshold range, the increase/decrease request value set for each of the plurality of power transmitting ends so that it falls within the threshold range and determining the corrected increase/decrease request value as the adjustment value of the supply power for the power transmitting end for which the determination is made.

7. The power network system according to any one of Claims 1 to 6, wherein when the power adjustment means externally receives the power request value, the power adjustment means calculates a difference between the received power request value and the current received power 100 value, and when the difference is equal to or greater than a predetermined value, adjusts the supply power.

8. The power network system according to any one of Claims 1 to 6, wherein the power adjustment means measures the current received power value in each of the plurality of power receiving ends at a predetermined interval, and when the difference between the measured received power value and the power request value is equal to or greater than a predetermined value, adjusts the supply power.

9. The power network system according to any one of Claims 1 to 8, wherein the power adjustment apparatus further comprises storage means for storing the power supply priority information.

10. A power adjustment apparatus connected to a power router through a communication network, the power router comprising: a DC bus maintained at a predetermined rated voltage; a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and control means for controlling the plurality of input/output end parts, wherein at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts, some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends, each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources, some of the plurality of input/output end parts included in the 101 second power router are used as a plurality of power receiving ends, each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends, the power adjustment apparatus comprises power adjustment means for adjusting the supply power according to a power request value requested in each of the plurality of power receiving ends, and the power adjustment means: acquires, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining the power transmitting end for which an adjustment of the supply power to be supplied to each of the plurality of power receiving ends should be prioritized; and determines a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and the priority defined in the power supply priority information.

11. A power adjustment method using a power router and a power adjustment apparatus connected to the power router through a communication network, the power router comprising: a DC bus maintained at a predetermined rated voltage; a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and control means for controlling the plurality of input/output end parts, wherein 102 at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts, and when: some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends; each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources; some of the plurality of input/output end parts included in the second power router are used as a plurality of power receiving ends; and each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends, the power adjustment apparatus: acquires, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining the power transmitting end for which an adjustment of the supply power to be supplied to each of the plurality of power receiving ends should be prioritized; determines a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and the priority defined in the power supply priority information; determines an adjustment value of supply power at the determined power transmitting end; and adjusts the supply power in each of the plurality of power transmitting ends based on the determined adjustment value.

12. A non-transitory computer readable medium storing a power 103 adjustment program for causing a computer connected to a power router through a communication network to execute a power adjustment process, the power router comprising: a DC bus maintained at a predetermined rated voltage; a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and control means for controlling the plurality of input/output end parts, wherein at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts, and when: some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends; each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources; some of the plurality of input/output end parts included in the second power router are used as a plurality of power receiving ends; and each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends, the power adjustment program causes the computer to execute: a process of acquiring, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining the power transmitting end for which an adjustment of the supply power to be 104 supplied to each of_the plurality of power receiving ends should be prioritized; a process of determining a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and.the priority defined in the power supply priority information; a process of determining an adjustment value of supply power at the determined power transmitting end; and h a process of adjusting the supply power in each of the plurality of power transmitting ends based on the determined adjustment value.

POWER NETWORK SYSTEM, AND POWER ADJUSTMENT APPARATUS AND METHOD
Technical Field [0001]
The present invention relates to a power network system, and a power adjustment apparatus, a method and a program. In particular, the present invention relates to a power network system, and a power adjustment apparatus, a method and a program capable of adjusting input/output power to an arbitrary value and capable of identifying a breakdown of power supply sources of received power.
Background Art [0002]
When a power supply system is constructed, in addition to a further expansion of a power distribution grid in a more stable way, a main issue has been providing such a system with a capability of introducing a large amount of natural energy. A power network system called Digital Grid (registered trademark) has been proposed as a new power network (see Patent literature 1 and Non-patent literature 1). Digital Grid (registered trademark) is a power network system in which a power network is partitioned into small-sized cells and these cells are asynchronously interconnected. Each power cell may be small (e.g., a house, a building, or a commercial facility) or may be large (e.g., a prefecture or a municipality). Each power cell naturally includes a load, and may also include a power generation facility or a power storage system. The power generation facility may be, as an example, a power generation facility that uses natural energy generated by, for example, photovoltaic power, wind power, and geothermal power. [0003]
In order to freely generate power inside each power cell and to further smoothly interchange power among the power cells, the power cells are asynchronously connected. (That is, even when the plurality of

2 power cells are interconnected, a frequency, a phase, and a voltage of
power used in each power cell are asynchronous with those used in other
power cells.) Fig. 71 shows an example of a power network system 10.
In Fig. 71, a utility grid 11 sends bulk power from a large-scale power plant 12. A plurality of power cells 21-24 is arranged. Each of the power cells 21-24 includes a load such as a house 31 and a building 32, power generation facilities 33 and 34, and a power storage system 35. The power generation facility may include, as an example, a solar panel 33 arid a wind turbine 34. The power storage system is, for example, a storage battery 35. In this specification, the power generation facility and the power storage system may be collectively called a distributed power supply. [0004]
Further, the power cells 21-24 respectively include power routers 41-44 which serve as connection ports to be connected to other power cells or the utility grid 11. Each of the power routers 41-44 includes a plurality of legs (LEG). (Due to space constraints, the symbols for the legs are omitted in Fig. 71. It should be interpreted that the white circles attached to the power routers 4 1-44 are connection terminals of each leg.)
Now, each leg includes a connection terminal and a power conversion unit, and an address is attached to each leg. The power conversion by the leg means converting AC to DC or DC to AC and changing the phase, the frequency, and the voltage of the power. [0005]
All the power routers 41-44 are connected to a management server 50 by a communication network 51 and operations of all the power routers 41-44 are integrally controlled by the management server 50. For example, the management server 50 instructs each of the power routers 41-44 to transmit or receive power for each leg using the address attached to each leg. Accordingly, power is interchanged among power cells through the power routers 41-44. [0006]
Since power interchange among the power cells is achieved, a

3 plurality of_j>_ower cells can share, for example, one p_ower generation
facility 33 or 34 or one power storage system 35. If an excessive power
can be interchanged among the power cells, a supply-demand balance of
power can be kept stable while greatly reducing the equipment cost.
[0007]
Further, Patent Literature 2 discloses a technique related to a
power system in which priorities are assigned to a plurality of loads to
which power is supplied according to the relative importance among the
plurality of loads. In the power system disclosed in Patent Literature 2,
for example, when the predicted available power is smaller than the
demand of the overall load, the balance between the demand and the
supply of the overall power in the system is adjusted by cancelling a
connection(s) to the input power source for a load(s) having low
importance.
Citation List
Patent Literature
[0008]
Patent Literature 1: Japanese Patent No. 4783453
Patent Literature 2: Japanese Unexamined Patent Application Publication
No. 2012-85516
Non Patent Literature
[0009]
Non-patent literature 1: Digital Grid Consortium, [searched on November
28, 2012], the Internet
Summary of Invention Technical Problem [0010]
If a plurality of power cells can be asynchronously connected by power routers, the advantage achieved by this asynchronous connection would be extremely large. It is thus desired that the power routers will be put into practical use at an early stage. [0011]

4 Incidentally, in Patent Literature 2, it is impossible to individually
change the priorities for the plurality of power supply sources, which are
the input power sources, among the plurality of loads (demanders to
which power is supplied from power receiving ends). That is, there is a
problem that it is impossible to cope with an individual need for the
power supply source, which is required in the customer of power in each
load. When the power network system like the one shown in Patent
Literature 1 is put into practical use in the future, it is expected that
power from a plurality of power supply sources is received in a mixed
manner and its breakdown can be identified (i.e., each of power supply
sources is identified). In such cases, there is a possibility that each of a
plurality of power customers individually changes the priorities of the
power supply sources.
[0012]
The present invention has been made to solve the above-described
problem and an object thereof is to provide a power network system, and a
power adjustment apparatus, a method and a program for adjusting power
supplies among a plurality of power receiving ends according to different
priorities for a plurality of power supply sources.
Solution to Problem [0013]
A power network system according to a first aspect of the present invention is a power network system including a plurality of power cells each including a power router for asynchronous connection to a power grid, in which
the power router includes:
a DC (Direct Current) bus maintained at a predetermined rated voltage;
a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one

connection end and the other connectionend; and
control means for controlling the plurality of input/output end parts,
at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts,
some oft he plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends,
:; each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources,
some of the plurality of input/output end parts included in the second power router are used as a plurality of power receiving ends,
each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends,
the power network system includes a power adjustment apparatus connected to the first and second power routers through a communication network, the power adjustment apparatus includes power adjustment means for adjusting the supply power according to a power request value requested in each of the plurality of power receiving ends, and
the power adjustment means:
acquires, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining a power transmitting end for which an adjustment of the supply power to be supplied to each of the plurality of power receiving ends should be prioritized; and
determines a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and the priority defined in the power

6
supply priority information.
[0014]
A power adjustment apparatus according to a second aspect of the present invention is a power adjustment apparatus connected to a power router through a communication network, the power router including;
a DC bus maintained at a predetermined rated voltage;
a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and
control means for controlling the plurality of input/output end parts, in which
at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts,
some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends,
each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources,
some of the plurality of input/output end parts included in the second power router are used as a plurality of power receiving ends,
each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends,
the power adjustment apparatus includes power adjustment means for adjusting the supply power according to a power request value requested in each of the plurality of power receiving ends, and
the power adjustment means:
acquires, for each of the plurality of power receiving ends, received power information including identification information of each

7 of the plurality of power transmitting ends and a value of supply power
supplied from each of the plurality of power transmitting ends, and power
supply priority information defining a priority for determining the power
transmitting end for which an adjustment of the supply power to be
supplied to each of the plurality of power receiving ends should be
prioritized; and
determines a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and the priority defined in the power supply priority information. [0015]
A power adjustment method according to a third aspect of the present invention is a power adjustment method using a power router and a power adjustment apparatus connected to the power router through a communication network, the power router including:
a DC bus maintained at a predetermined rated voltage;
a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an.external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and
control means for controlling the plurality of input/ouLput end parts, in which
at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts, and
when:
some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends;
each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources;
some of the plurality of input/output end parts included in the

8 second power router are used as a plurality of power receiving ends; and
each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends,
the power adjustment apparatus:
acquires, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining the power transmitting end for which an adjustment of the supply power to be supplied to each of the plurality of power receiving ends should be prioritized;
determines a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and the priority defined in the power supply priority information;
determines an adjustment value of supply power at the determined power transmitting end; and
adjusts the supply power in each of the plurality of power transmitting ends based on the determined adjustment value. [0016]
A power adjustment program according to a fourth aspect of the present invention is a non-transitory computer readable medium storing a power adjustment program for causing a computer connected to a power router through a communication network to execute a power adjustment process, the power router including:
a DC bus maintained at a predetermined rated voltage;
a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one

9 connection en_d__and the other connection end; and
control means for controlling the plurality of input/output end parts, in which
at least first and second power routers among the plurality of 5 power routers are connected to each other by respective input/output end parts, and
when:
some of the plurality of input/output end parts included in the first
power router are used as a plurality of power transmitting ends;
1 0 each of the plurality of power transmitting ends supplies supply
power to the second power router, the supply power being supplied from one of a plurality of power supply sources;
some of the plurality of input/output end parts included in the second power router are used as a plurality of power receiving ends; and
1 5 each of the plurality of power receiving ends receives supply
power through the DC bus and supplies the received power to one of a plurality of power dernanders, the supply power being supplied from each of the plurality of power transmitting ends,
the power adjustment program causes the computer to execute:
2 0 a process of acquiring, for each of the plurality of power receiving
ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining the 25 power transmitting end for which an adjustment of the supply power to be supplied to each of the plurality of power receiving ends should be prioritized;
a process of determining a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting
3 0 ends based on the received power information and the priority defined in
the power supply priority information;
a process of determining an adjustment value of supply power at the determined power transmitting end; and
a process of adjusting the supply power in each of the plurality of

10 power transmitting ends based on the determined_adjustment value.

10
1 5
20
25
3 0

Advantageous Effects of Invention [0017]
According to the present invention, it is possible to provide a power network system, and a power adjustment apparatus, a method and a program for adjusting power supplies among a plurality of power receiving ends according to different priorities for a plurality of power supply sources.
Brief Description of Drawings [0018]
Fig. 1 is a block diagram showing a general configuration of a power router according to each exemplary embodiment of the present invention;
Fig. 2 is a block diagram showing showing details of an internal configuration of a power router according to each exemplary embodiment of the present invention;
Fig. 3 shows an example in which a power router is connected to a utility grid, a load, and various distributed power supply;
Fig. 4 shows an example of a possible combination of a connection between power routers;
Fig. 5 shows an example of a possible combination of a connection between power routers;
Fig. 6 shows an example of a prohibited combination of a connection between power routers;
Fig. 7 shows an example of a prohibited combination of a connection between power routers;
Fig. 8 shows an example of a prohibited combination of a connection between power routers;
Fig. 9 shows an example of a prohibited combination of a connection between power routers;
Fig. 10 shows an example of possible combination of a connection between power routers in which an AC-through leg is taken into

11
consideration;
Fig. 11 shows an example of possible combination of a connection
between power routers in which an AC-through leg is taken into
consideration;
5 Fig. 12 shows an example of possible combination of a connection
between power routers in which an AC-through leg is taken into consideration;
Fig. 13 shows an example of possible combination of a connection between power routers in which an AC-through leg is taken into 1 0 consideration;
Fig. 14 shows a connection example using an AC-through leg;
Fig. 15 is a table in which combination patterns for a connection between power routers are summarized;
Fig. 16 shows an example in which four power routers are
1 5 connected to each other;
Fig. 17 shows an example where a plurality of power routers are connected through a bus;
Fig. 18 shows an example of a connection form in which a utility
grid is interposed between power routers;
20 Fig. 19 is a block diagram showing a configuration of a power
network system according to an example 1 of a power identification technique;
Fig. 20 is a block diagram showing a configuration of a central control device according to the example 1 of the power identification
2 5 technique;
Fig. 21 shows an example of power transmission according to the example 1 of the power identification technique;
Fig. 22 is a sequence diagram of a power transmission process according to the example 1 of the power identification technique;
3 0 Fig. 23 shows an example of an input/output terminal setting
management table according to the example 1 of the power identification technique;
Fig. 24 shows an example of power transmission route information according to the example 1 of the power identification technique;

12 Fig. 25 shows an example of a measurement tag according to the
example 1 of the power identification technique;
Fig. 26 shows an example of a power tag according to the example
1 of the power identification technique;
5 Fig. 27 is a flowchart showing a power tag generation process flow
according to the example 1 of the power identification technique;
Fig. 28 shows a configuration example of power information
according to the example 1 of the power identification technique;
Fig. 29 is a flowchart showing a power information generation
1 0 process flow according to the example 1 of the power identification
technique;
Fig. 30 is a block diagram showing a configuration of a power
network system according to an example 2 of a power identification
technique;
1 5 Fig. 31 is a block diagram showing a configuration of a central
control device according to the example 2 of the power identification
technique;
Fig. 32 shows an example of correspondence between input
voltages and output voltages according to the example 2 of the power
20 identification technique;
Fig. 33 shows an example of correspondence between input
voltages and output voltages according to the example 2 of the power
identification technique;
Fig. 34 shows an example of a power interchange according to the
25 example 2 of the power identification technique;
Fig. 35 shows an example of a power transmission/reception
transaction contract information management table according to the
example 2 of the power identification technique;
Fig. 36 shows an example of an input/output terminal setting
3 0 management table according to the example 2 of the power identification
technique;
Fig. 37 shows an example of a correspondence table between power
transmission/reception contract information and input/output terminal
settings according to the example 2 of the power identification technique;

13 Fig. 38 shows an example of power transmission route information
according to the example 2 of the power identification technique;
Fig. 39 shows an example of a measurement tag according to the
example 2 of the power identification technique;
5 Fig. 40 is a flowchart showing a power tag generation process flow
according to the example 2 of the power identification technique;
Fig. 41 shows an example of breakdown information according to
the example 2 of the power identification technique;
!: Fig. 42 shows a calculation example of breakdown information
1 0 according to the example 2 of the power identification technique;
Fig. 43 shows an example of a power tag according to the example
2 of the power identification technique;
Fig. 44 is a block diagram showing a configuration of a power
network system according to a first exemplary embodiment of the present
1 5 invention;
Fig. 45 is a block diagram showing a configuration of a central
control device according to the first exemplary embodiment of the present
invention;
Fig. 46 shows an example of power supply priority information
20 according to the first exemplary embodiment of the present invention;
Fig. 47 is a flowchart showing an outline of a power adjustment
process according to the first exemplary embodiment of the present
invention;
Fig. 48 is a flowchart showing an Initialize subroutine flow in the
25 power adjustment process according to the first exemplary embodiment of
the present invention;
Fig. 49 is a flowchart showing a Request Generation subroutine
flow in the power adjustment process according to the first exemplary
embodiment of the present invention;
3 0 Fig. 50 is a flowchart showing an Update Determination subroutine
flow in the power adjustment process according to the first exemplary
embodiment of the present invention;
Fig. 51 is a flowchart showing a Loop Control subroutine flow in
the power adjustment process according to the first exemplary

14 embodiment of the present invention;
Fig. 52 shows an example of a power adjustment according to the first exemplary embodiment of the present invention;
Fig. 53 shows an example of a power adjustment according to the 5 first exemplary embodiment of the present invention;
Fig. 54 shows an example of a power adjustment according to the first exemplary embodiment of the present invention;
Fig. 55 shows an example of a power adjustment according to the
first exemplary embodiment of the present invention;
1 0 Fig. 56 shows an example of a power adjustment according to the
first exemplary embodiment of the present invention;
Fig. 57 shows an example of a power adjustment according to the first exemplary embodiment of the present invention;
Fig. 58 shows an example of a power adjustment according to the 15 first exemplary embodiment of the present invention;
Fig. 59 shows an example of a power adjustment according to the first exemplary embodiment of the present invention;
Fig. 60 shows an example of a power adjustment according to the
first exemplary embodiment of the present invention;
20 Fig. 61 shows an example of a power adjustment according to the
first exemplary embodiment of the present invention;
Fig. 62 shows an example of a power adjustment according to the first exemplary embodiment of the present invention;
Fig. 63 shows an example of changes in values before and after 25 power adjustments at power transmitting ends according to the first exemplary embodiment of the present invention;
Fig. 64 shows an example of changes in values before and after
power adjustments at power transmitting ends according to the first
exemplary embodiment of the present invention;
3 0 Fig. 65 is a block diagram showing a configuration of a power
network system according to a second exemplary embodiment of the present invention;
Fig. 66 is a block diagram showing a configuration of a central control device according to the second exemplary embodiment of the

15
present invention^;
Fig. 67 shows an example of pOAver demand priority information
according to the second exemplary embodiment of the present invention;
Fig. 68 shows another example of power demand priority
5 information according to the second exemplary embodiment of the present
invention;
Fig. 69 is a flowchart showing a power adjustment process flow
according to the second exemplary embodiment of the present invention;
; Fig. 70 is a flowchart showing a power adjustment process flow
1 0 according to a third exemplary embodiment of the present invention; and
Fig. 71 is a diagram for explaining an outline of a power network
system.
Description of Embodiments 15 [0019]
Specific exemplary embodiments to which the present invention is applied are explained hereinafter in detail with reference to the drawings. The same components are denoted by the same symbols throughout the drawings, and duplicated explanation is omitted as necessary for 20 clarifying the explanation. [0020]
Firstly, a configuration of a power router that is in common in exemplary embodiments according to the present invention is explained.
Fig. 1 is a diagram showing a schematic configuration of a power 25 router 100.
Further, Fig.2 is a diagram showing the details of an internal configuration of the power router 100.
In general, the power router 100 includes a DC (Direct Current) bus 101, a plurality of legs 110-160, and a controller 190. 30 [0021]
The power router 100 includes the DC bus 101 to which the plurality of legs 110-160 are connected in parallel. The DC bus 101 is provided to enable DC power flow, and a voltage of the DC bus 101 is controlled to be constant.

16 (How the voltage of the DC bus 101 is kept constant will be
described later.)
The power router 100 is connected to the outside through each of
the legs 1 10-160. All the power to be exchanged with the outside is once
5 converted into DC and the DC flows through the DC bus 101. Since
power is once converted into DC, it is possible to asynchronously connect
power cells without any consideration for the differences in the phase, the
voltage, or the frequency thereof. It is assumed here that the DC bus
101 is, as shown in Fig. 2, a parallel type including a smoothing capacitor
1 0 102. A voltage sensor 103 is connected to the DC bus 101, and a voltage value of the DC bus 101 detected by the voltage sensor 103 is sent to the controller 190. [0022]
Next, the plurality of legs 110-160 will be described. The
15 plurality of legs 110-160 are provided in parallel with the DC bus. In
Fig. 1, six legs 110-160 are shown. The six legs 1 10-160 are represented, as shown in Fig. 1, as a first leg 110, a second leg 120, . . . , and a sixth leg 160. In Fig. 1, due to space constraints, the first leg 110 is denoted by a leg 1 and the second leg 120 is denoted by a leg 2, for example.
20 Further, in Fig. 2, the third leg 130, the fourth leg 140, and the sixth leg 1 60 are omitted. [0023]
While the first leg 110 to the fifth leg 150 have the same configuration, the sixth leg 160 is different from the first to fifth legs
25 110-150 in that the sixth leg 160 does not include a power conversion unit. First, the configuration of the first leg 110 to the fifth leg 150 will be described. Since the first leg 110 to the fifth leg 150 have the same configuration, just the configuration of the.first leg 110 will be described as an example. The first leg 1 10 includes a power conversion unit 1 1 1, a
30 current sensor 112, a switch 113, a voltage sensor 114, and a connection terminal 115. The power conversion unit 111 converts AC power to DC power or DC power to AC power. Since DC power flows through the DC bus 101, the power conversion unit 111 converts DC power flowing through the DC bus 101 to AC power having a predetermined frequency

17 and_vpltage to allow the AC power to flow to the outside from the
connection terminal 115. Otherwise, the power conversion unit 111
converts AC power that flows from the connection terminal 115 into DC
power to allow the DC power to flow through the DC bus 101.
5 [0024]
The power conversion unit 111 has a configuration of an inverter
circuit in which anti-parallel circuits 1 1 IP formed of power conversion
elements 111T and feedback diodes 111D are three-phase
bridge-connected. (That is, six anti-parallel circuits 111P are provided
1 0 for one inverter circuit.)
While the power conversion unit 111 is a three-phase inverter circuit since the three-phase AC is used in this example, a single-phase inverter circuit may be used instead. A line that is drawn from a node between two anti-parallel circuits 11 IP and connects the node and the
1 5 connection terminal is called a branch line BL. (Since the three-phase AC is used, one leg includes three branch lines BL.)
Note that for the power conversion elements, thyristors, which are externally commutated power conversion elements, IGBTs (Insulated Gate Bipolar Transistors), which are self-commutated power conversion
20 elements, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), or the like can be used. [0025]
The direction of the power, the frequency of the AC power and the like are controlled by the controller 190. That is, switching operations
25 of the power conversion elements HIT are controlled by the controller 190. The operation control by the controller 190 will be described later. [0026]
The switch 113 is provided between the power conversion unit 111 and the connection terminal 115. The branch line BL is opened or closed
3 0 by the operation of the switch 113, which means the connection between the outside and the DC bus 101 is broken or established. Further, the voltage of the branch line BL is detected by the voltage sensor 1 14 and the current value of the current flowing through the branch line BL is detected by the current sensor 112. The switching operation of the

18 switch 113 is controlled by the controller 190 and the values detected by
the voltage sensor 1 14 and the current sensor 112 are output to the
controller 1 90.
[0027]
While the power conversion unit is the inverter circuit and the connection partner of the leg uses AC as described above, the connection partner of the leg may instead use DC and may be, for example, a storage battery 35. (For example, in Fig. 1, the third leg 130 is connected to the storage battery 35.)
The power conversion in this case is DC-DC conversion. Accordingly, it is possible to provide an inverter circuit and a converter circuit in parallel in the power conversion unit and separately use the inverter circuit and the converter circuit depending on whether the connection partner is AC or DC. Otherwise, a leg dedicated for DC-DC conversion in which the power conversion unit is a DC-DC conversion unit may be provided. It will be often advantageous in terms of the size and the cost to use a power router that includes both a leg dedicated for AC-DC conversion and a leg dedicated for DC-DC conversion instead of providing the inverter circuit and the converter circuit in parallel in each leg. [0028]
The first leg 110 to the fifth leg 150 have the same configuration stated above. [0029]
Next, the sixth leg 160 will be described. The sixth leg 160 does not include a power conversion unit, which means a connection terminal 165 of the sixth leg 160 is not connected to the DC bus 101. The sixth leg 160 is connected to the branch line BL of the fifth leg 150. An internal wire of the sixth leg 160 is also called a branch line BL. The branch line BL of the sixth leg 160 is connected between the connection terminal 155 and the switch 153 of the fifth leg 150. [0030]
The sixth leg 160 includes a switch 163, a voltage sensor 164, a current sensor 162, and a connection terminal 165. The branch line BL

19 of the sixth leg 160 is connected to the branch line BL of the fifth leg 150
through the switch 163. That is, the connection terminal 165 of the sixth
leg 160 is connected to the connection terminal 155 of the fifth leg 150.
Only the switch 163 is provided between the connection terminal 165 of
5 the sixth leg 160 and the connection terminal 155 of the fifth leg 150 and
the sixth leg 160 does not include a power converter. Accordingly,
power is conducted between the connection terminal 165 of the sixth leg
160 and the connection terminal 155 of the fifth leg 150 without being
converted. A leg such as the sixth leg 160 that does not include a power
10 converter may be called an AC-through leg. [0031]
The current sensor 162 and the voltage sensor 164 detect a current value and a voltage value of the branch line BL to output the current value and the voltage value to the controller 190. The switching
1 5 operation of the switch 163 is controlled by the controller 190. [0032] (Operation modes of legs)
The first leg 110 to the fifth leg 150 include power converters 111-151 and the switching operations ofthepower conversion elements in
20 the power converters are controlled by the controller 190, as already described above.
Note that the power router 100 is in the node of the power network 10, and plays an important role of connecting the utility grid 11, the load 30, a distributed power supply, power cells and the like. At this time,
25 the connection terminals 115-165 of the respective legs 110-160 are
connected to the utility grid 11, the load 30, the distributed power supply, and power routers of other power cells. The present inventors have noticed that the legs 110-160 have different roles depending on the connection partner and the power routers are not appropriately operated
30 unless each of the legs 110-160 is appropriately operated according to each of their respective roles. While the legs have the same configuration, the present inventors have changed the method of operating the legs depending on the connection partner.
The method of operating the legs is called an operation mode.

20 The present inventors have prepared three types of operation modes
of the legs, and the modes are switched according to the connection
partner.
The operation modes of the legs include:
5 a master mode;
a stand-alone mode; and
a designated power transmission/reception mode.
In the following description, these operation modes will be described in series. 10 [0033]
(Master mode)
The master mode is an operation mode when a leg is connected to a stable power supply source such as an electrical grid, and is an operation mode to keep the voltage ofthe DC bus 101. In Fig. 1, an example in 15 which the connection terminal 115 ofthe first leg 110 is connected to the utility grid 1 1 is shown. In the case of Fig. 1, the operation of the first leg 110 is controlled as a master mode, and plays a role of keeping the voltage ofthe DC bus 101. While many other legs 120-150 are connected to the DC bus 101, power may flow into the DC bus 101 from 20 the legs 120-150 or may flow out from the legs 120-150. When the
power flows out through the DC bus 101 and the voltage ofthe DC bus 101 decreases from the rated voltage, the leg 110 which is in the master mode supplements an insufficient energy due to the outflow from the connection partner (in this example, the utility grid 11). On the other 25 hand, when the power flows into the DC bus 101 and the voltage ofthe DC bus 101 increases from the rated voltage, the leg 110 which is in the master mode transfers an excessive energy due to the inflow to the connection partner (in this example, the utility grid 11). The leg 1 10 which is in the master mode is therefore able to keep the voltage of the 30 DC bus 101.
Accordingly, in one power router, at least one leg needs to be operated in the master mode. Otherwise, the voltage ofthe DC bus 101 is not kept constant. In one power router, two or more legs may be operated in the master mode. It is preferable, however, that only one leg

21 be operated in the master mode in one power router. Further, for
example, the leg which in the master mode may be connected to the
distributed power supply (also including storage batteries) on which a
self-commutated inverter is mounted instead of being connected to the
5 utility grid. It is impossible, however, to connect the leg which is in the
master mode and the distributed power supply on which an externally
commutated inverter is mounted.
[0034]
In the following description, the leg operated in the master mode
1 0 may be referred to as a master leg.
[0035]
The operation control of the master leg will be described.
The master leg is started as follows.
First, the switch 113 is set to the opened (broken) state. In this
1 5 state, the connection terminal 1 15 is connected to the connection partner.
In this embodiment, the connection partner is the utility grid 11.
The voltage sensor 114 measures the voltage of the utility grid of
the connection partner and obtains the phase, the frequency, and the
amplitude of the voltage of the utility grid using a phase-locked loop
20 (PLL) or the like. After that, the output of the power conversion unit
111 is adjusted so that the voltage of the phase, the frequency, and the
amplitude that are obtained is output from the power conversion unit 111.
That is, the ON/OFF patterns of the power conversion elements 111T are
determined. When this output is made stable, the switch 113 is turned
25 on and the power conversion unit 111 and the utility grid 11 are connected.
Since the output of the power conversion unit 111 and the voltage of the
utility grid 1 1 are synchronized at this point, the current does not flow.
[0036]
The operation control when the master leg is operated will be
3 0 described.
The voltage of the DC bus 101 is measured by the voltage sensor
103. When the voltage of the DC bus 101 exceeds a predetermined rated
bus voltage, the power conversion unit 111 is controlled so that power is
sent from the master leg 110 to the utility grid. (At least one of the phase

22 and the amplitude of the voltage output from the powexconversion unit
1-11 is adjusted so that power is sent from the DC bus 101 to the utility
grid 1 1 through the master leg 1 10.) The rated voltage of the DC bus
101 is predetermined. 5 [0037]
On the other hand, when the voltage of the DC bus 101 is below the
predetermined rated bus voltage, the power conversion unit 111 is
controlled so that the master leg 110 is able to receive power from the
utility grid 11. (At least one of the phase and the amplitude of the voltage 1 0 output from the power conversion unit 11 1 is adjusted so that power is
sent from the utility grid 11 to the DC bus 101 through the master leg
110.) It will be understood that, according to the operation of the
master leg as described above, the voltage of the DC bus 101 can be kept
to the predetermined rated voltage. 15 [0038]
(Stand-alone mode)
The stand-alone mode is an operation mode in which a leg
generates a voltage of the amplitude and the frequency specified by the
management server 50 by itself, and sends power to and receives power 20 from the connection partner.
The stand-alone mode is, for example, an operation mode to supply
power to a device such as the load 30 that consumes power.
Alternatively, the stand-alone mode is an operation mode to directly
receive power sent from the connection partner.
25 Fig. 1 shows an example in which the connection terminal 125 of
the second leg 120 is connected to the load 30. The operation of the
second leg 120 is controlled as the stand-alone mode and power is
supplied to the load 30.
Further, when a leg is connected to another power router as in the 3 0 fourth leg 140 or the fifth leg 150, the fourth leg 140 or the fifth leg 150
may be operated in the stand-alone mode as a mode to send power
required by the other power router.
Alternatively, when a leg is connected to another power router as
in the fourth leg 140 or the fifth leg 150, the fourth leg 140 or the fifth

23 leg 1 50_ may be operated in the stand-alone modeas a mode to receive
power sent from the other power router.
While it is not illustrated in the drawings, the second leg can be
operated in the stand-alone mode also in a case in which the second leg is 5 connected to a power generation facility in place of the load 30. Tn this
case, however, an externally commutated inverter is installed in the
power generation facility.
The operation mode when the power routers are connected to each
otherl'will be described later. 10 [0039]
The leg operated in the stand-alone mode is called a stand-alone
leg. In one power router, a plurality of stand-alone legs may be
provided.
[0040]
15 The operation control of the stand-alone leg will be described.
First, a switch 123 is opened (broken). The connection terminal
125 is connected to the load 30. The management server 50 notifies the
power router 100 of the amplitude and the frequency of the power
(voltage) that should be supplied to the load 30. The controller 190 20 causes the power (voltage) of the specified frequency and the specified
amplitude to be output from the power conversion unit 121 to the load 30.
(In short, the ON/OFF patterns of the power conversion elements 121T are
determined.) When this output becomes stable, the switch 123 is turned
on to connect the power conversion unit 121 and the load 30. Lastly, 25 when the power is consumed in the load 30, the power corresponding to
the consumed amount flows out to the load 30 from the stand-alone leg
120.
[0041]
(Designated power transmission/reception mode)
3 0 A designated power transmission/reception mode is an operation
mode for transmitting or receiving a designated energy. Specifically,
the designated power transmission/reception mode includes a case in
which the designated power is transmitted to the connection partner and a
case in which the designated power is received from the connection

24
_ partner.
In Fig. 1, the fourth leg 140 and the fifth leg 150 are connected to
other power routers.
In such a case, a predetermined energy is fed from the fourth leg
5 140 or the fifth leg 150 to the other power router or from the other power
router to the fourth leg 140 or the fifth leg 150.
Alternatively, the third leg 130 is connected to the storage battery
35.
;. In such a case, a predetermined energy is sent to the storage
1 0 battery 35 to charge the storage battery 35.
Further, the designated power transmission/reception leg and the
distributed power supply (also including the storage battery) on which a
self-commutated inverter is mounted may be connected. However, the
designated power transmission/reception leg and the distributed power
1 5 supply on which an externally commutated inverter is mounted cannot be
connected.
[0042]
The leg operated in the designated power transmission/reception
mode is called a designated power transmission/reception leg. In one
20 power router, a plurality of designated power transmission/reception legs
may be provided.
[0043]
The operation control of the designated power
transmission/reception leg will be described. Since the control when the
25 designated power transmission/reception leg is started is basically the
same as that when the master leg is started, a description thereof will be
omitted.
[0044]
The operation control when the designated power
30 transmission/reception leg is operated will be described.
(In the following description, symbols attached to the components
of the fifth leg 150 will be used.)
A voltage sensor 154 measures the voltage of the electrical grid of
the connection partner to obtain the phase and the frequency of the

25 voltage of the connection partner using a phase-locked loop (PLL) or the
like. The target value of the current that the power converter 151
receives or outputs is obtained based on an active power value and a
reactive power value specified by the management server 50 and the phase
5 and the frequency of the voltage of the connection partner. A current
sensor 152 measures the current value of the current. The power
converter 151 is adjusted so that the current corresponding to the
difference between the target value and the current value is additionally
output. (At least one of the phase and the amplitude of the voltage output
10 from the power conversion unit 151 is adjusted so that a desired power
flows between the designated power transmission/reception leg and the
connection partner.)
[0045]
From the above description, it will be understood that the first to
1 5 fifth legs having the same configuration can play roles having three
different patterns according to the method of the operation control.
[0046]
(Connection restrictions)
Since the operations of the legs vary according to the difference in
20 the operation mode, there are respective restrictions regarding the
selection of the connection partner and the selection of the operation
mode. That is, when the connection partner is determined, the operation
mode that can be selected is determined, and in contrast, when the
operation mode is determined, the connection partner that can be selected
25 is determined. (When the connection partner is changed, the operation
mode of the leg needs to be changed according to the change of the
connection partner.)
Patterns of possible combinations of connections will be described
below.
30 [0047]
In the following description, the expressions in the diagrams are
simplified as shown in Fig. 3.
Specifically, the master leg is denoted by M.
The stand-alone leg is denoted by S.

26 The designated power transmission/reception leg is denoted by D,
The AC-through leg is denoted by AC.
Further, the legs may be differentiated from one another by
numbers such as "#1" attached to the top of the legs as necessary.
5 While systematized symbols are attached for each of figures
starting from Fig. 3, the same elements arc not necessarily denoted by the same reference symbols throughout the drawings.
For example, the symbol 200 in Fig. 3 and the symbol 200 in Fig. 4 do not indicate the same component. 10 [0048]
All the combinations of the connections shown in Fig. 3 are available. A first leg 210 is connected to the utility grid 1 1 as a master leg. This connection has already been described above.
A second leg 220 is connected to the load 30 as the stand-alone leg. 1 5 This connection has already been described above as well.
A third leg 230 and a fourth leg 240 are connected to the storage
battery 35 as the designated power transmission/reception legs. This
connection has already been described above as well.
[0049]
20 A fifth leg 250 is an AC-through leg. The AC-through leg 250 is
connected to the designated power transmission/reception leg of another
power router 300 and the AC-through leg 250 is connected to the storage
battery 35 through a connection terminal 245 of the fourth leg 240.
Since the AC-through leg 250 does not include a power conversion unit,
25 this above connection relation is equivalent to the state in which the
designated power transmission/reception leg of the other power router
300 is directly connected to the storage battery 35. It is understood that
such a connection is permitted.
[0050]
30 A sixth leg 260 is connected to the utility grid 11 as the designated
power transmission/reception leg. If it is assumed that a predetermined power is received from the utility grid 11 through the sixth leg 260, it is understood that such a connection is permitted.
Considering that the first leg 210 is the master leg, if the power

27 received by the sixth leg 260 is insufficient to keep the voltage of the DC
bus 201 to the rated voltage, the master leg 210 receives necessary power
from the utility grid 11. In contrast, when the power received by the
sixth leg 260 exceeds the amount that is necessary to keep the voltage of
5 the DC bus 201 to the rated voltage, the master leg 210 transfers
excessive power to the utility grid 11.
[0051]
Next, a case in which the power routers are connected to each other
will .be described. Connecting the power routers means connecting a leg
10 of one power router and a leg of another power router. When the legs are connected to each other, the operation modes that can be combined are restricted. [0052]
Both of the combinations of the connections shown in Figs. 4 and 5
1 5 are available. In Fig. 4A, the master leg 1 10 of the first power router 100 and the stand-alone leg 210 of the second power router 200 are connected. While the details of this connection will not be described, the master leg 220 of the second power router 200 is connected to the utility grid 11, whereby the voltage of the DC bus 201 of the second
20 power router 200 is kept to be the rated voltage. [0053]
In Fig. 4, when power is supplied to the load 30 from the first power router 100, the voltage of the DC bus 101 decreases. The master leg 110 obtains power from the connection partner so as to keep the
25 voltage of the DC bus 101. That is, the master leg 110 draws
insufficient power from the stand-alone leg 210 of the second power router 200. The stand-alone leg 210 of the second power router 200 sends power required from the connection partner (in this example, the master leg 110). While the voltage decreases by the energy sent from
30 the stand-alone leg 210 in the DC bus 201 of the second power router 200, this is supplemented from the utility grid 11 by the master leg 220. In this way, the first power router 100 can obtain a necessary energy from the second power router 200. [0054]

28 As described above, even when the master leg 11 0 of the first
power router 100 and the stand-alone leg 210 of the second power router
200 are connected, each of the master leg 110 and the stand-alone leg 210
can each play a role. Therefore, no disadvantage occurs in each of the
5 operations in the master leg 110 and the stand-alone leg 210.
Accordingly, the master leg and the stand-alone leg may be connected as
shown in Fig. 4.
[0055]
In Fig. 5, a designated power transmission/reception leg 310 of the
10 third power router 300 and a stand-alone leg 410 of the fourth power
router 400 are connected. While not described in detail, a master leg
320 of the third power router 300 and a master leg 420 of the fourth power
router 400 are each connected to the utility grid 11. DC buses 301 and
401 of the third power router 300 and the fourth power router 400 thus
1 5 keep the rated voltage.
[0056]
It is assumed that the designated power transmission/reception leg 310 of the third power router 300 is instructed to receive a designated power according to the instruction from the management server 50. The 20 designated power transmission/reception leg 310 draws the designated
power from the stand-alone leg 410 of the fourth power router 400. The stand-alone leg 410 of the fourth power router 400 sends power required from the connection partner (in this example, the designated power transmission/reception leg 310). While the voltage of the DC bus 401 of
2 5 the fourth power router 400 decreases by the energy sent from the
stand-alone leg 410, this is supplemented from the utility grid 1 1 by the
master leg 420.
[0057]
As described above, even when the designated power
3 0 transmission/reception leg 310 of the third power router 300 and the
stand-alone leg 410 of the fourth power router 400 are connected, the designated power transmission/reception leg 310 and the stand-alone leg 410 can each play a role. Therefore, no disadvantage occurs in each of the operations in the designated power transmission/reception leg 310 and

29 the stand-alone leg 410. Accordingly, the designated power
transmission/reception leg and the stand-alone leg may be connected as
shown in Fig. 5.
[0058]
5 While the case in which the third power router 300 obtains power
from the fourth power router 400 has been described above, it should be
understood that there is also no disadvantage in a case in which the third
power router 300 gives power to the fourth power router 400.
[005:9]
10 It is therefore possible to interchange the designated power
between the third power router 300 and the fourth power router 400. [0060]
When the legs having the power conversion units are directly connected to each other, only two connection patterns shown in Figs. 4 1 5 and 5 are permitted.
Specifically, only the case in which the master leg and the stand-alone leg are connected and the case in which the designated power transmission/reception leg and the stand-alone leg are connected are permitted. 20 [0061]
Next, combinations of the legs that cannot be connected will be described.
Figs. 6 to 9 are patterns in which legs should not be connected.
As shown in Figs. 6, 7, and 8, the legs that are in the same 25 operation mode must not be connected.
In the case of Fig. 6, for example, the master legs are connected.
The master leg first performs processing for generating power in synchronization with the phase, the frequency, and the voltage of the connection partner, as described above in the description of the 3 0 operation.
When the connection partner is also a master leg, each master leg tries to be synchronized with the voltage and the frequency of the other master leg. However, since the master leg does not establish the voltage and the frequency in a stand-alone manner, the synchronous processing

30
stated above does not succeed.
Therefore, the master legs cannot be connected to each other.
There are other reasons why the master legs cannot be connected to
each other as follows.
5 The master leg needs to draw power from the connection partner in
order to keep the voltage of the DC bus. (Otherwise excessive power needs to be made to flow out to the connection partner in order to keep the voltage of the DC bus.) When the master legs are connected to each other, each master leg cannot meet the requirements of the connection 1 0 partner. (If the master legs are connected to each other, neither of the power routers can keep the voltage of the DC bus. This may cause a malfunction such as blackout in each power cell.) In this way, if the master legs are connected to each other, the roles of the master legs conflict with each other (do not match). The master legs therefore must 1 5 not be connected to each other. [0062]
While the designated power transmission/reception legs are
connected to each other in Fig. 7, it should be understood that this
connection is not available as well.
20 As described above in the description of the operation, similar to
the master leg, the designated power transmission/reception leg first performs processing for generating power in synchronization with the phase, the frequency, and the voltage of the connection partner.
When the connection partner is also a designated power
25 transmission/reception leg, each leg tries to be synchronized with the
voltage and the frequency of the other leg. However, since the
designated power transmission/reception leg does not establish the
voltage and frequency in a stand-alone manner, the synchronous
processing stated above does not succeed.
3 0 Therefore, the designated power transmission/reception legs
cannot be connected to each other.
There are other reasons why the above legs cannot be connected to each other as follows.
Even if the designated transmitted power that should be sent by one

31
designated power transmission/reception leg 510 is made equal to the
designated received power that should be received by the other designated
power transmission/reception leg 610, such designated power
transmission/reception legs should not be connected to each other.
5 Assume a case, for example, in which one designated power
transmission/reception leg 510 adjusts the power conversion unit to send
the designated transmitted power. (For example, the output voltage is
made higher than that of the connection partner by a predetermined
value.) On the other hand, the other designated power
10 transmission/reception leg 610 adjusts the power conversion unit to
receive the designated received power. (For example, the output voltage is made lower than that of the connection partner by a predetermined value.) It will be understood that, when such an adjustment operation is executed in both of the designated power transmission/reception legs 510
1 5 and 610 at the same time, both of the designated power
transmission/reception legs 510 and 610 become uncontrollable. [0063]
While the stand-alone legs are connected in Fig. 8, it should be understood that such a connection is prohibited.
20 The stand-alone leg generates a voltage and a frequency by itself.
If one of the voltage, the frequency, and the phase generated by the two stand-alone legs is deviated from the other by even a slight amount in a state in which the stand-alone legs are connected, unintended power flows between the two stand-alone legs.
25 It is impossible to completely keep the voltage, the frequency, and
the phase generated by the two stand-alone legs to be equal. Therefore, the stand-alone legs should not be connected. [0064]
In Fig. 9, the master leg and the designated power
3 0 transmission/reception leg are connected.
It should be understood from the above description that this connection is not available as well. Even when the master leg 510 transmits power to or receives power from the connection partner to keep the voltage of the DC bus 501, the designated power

32
transmission/reception leg 610 does not transmit or receive power
according to the request from the master leg 510. Accordingly, the
master leg 510 cannot keep the voltage of the DC bus 501. Further, even
when the designated power transmission/reception leg 610 transmits
5 designated power to or receives it from the connection partner (510), the
master leg 510 does not transmit or receive power according to the
request from the designated power transmission/reception leg 610.
Accordingly, the designated power transmission/reception leg 610 cannot
transmit the designated power to or receive it from the connection partner
10 (in this example, the master leg 510). [0065]
The case in which the legs including power conversion units are connected has been stated above. When an AC-through leg is taken into consideration, patterns shown in Figs. 10 to 13 are also available. Since
1 5 the AC-through leg does not include a power conversion unit, it is a
simple bypass. Accordingly, as shown in Figs. 10 and 13, the situation in which the master leg 110 of the first power router 100 is connected to the utility grid 11 through the AC-through leg 250 of the second power router 200 is substantially equal to the situation in which the master leg
20 110 is directly connected to the utility grid 11. In a similar way, as shown in Figs. 12 and 13, the situation in which the designated power transmission/reception leg 110 of the first power router 100 is connected to the utility grid 1 1 through the AC-through leg 250 of the second power router 200 is substantially equal to the situation in which the designated
25 power transmission/reception leg 110 is directly connected to the utility grid 11. [0066]
Still, it is convenient to provide the AC-through leg. There may be a case, for example, in which the distance from the first power router
3 0 100 to the utility grid 11 is extremely long and some power routers 200 and 300 need to be passed to connect the first power router 100 to the utility grid 11, as shown in Fig. 14.
If it is assumed that the AC-through leg is not provided, as shown in Fig. 4, one or a plurality of stand-alone legs need to be passed. When

33 a leg including a power_cpnversion unit is passed, it requires conversion
from AC power into DC power and conversion from DC power into AC
power. The power conversion causes an energy loss, though the loss is
low (several %). It is inefficient to require a power conversion a
5 plurality of times only to connect the power router to the utility grid.
It is therefore preferable that the AC-through leg which does not include a power conversion unit is provided in the power router. [0067]
Fig. 15 shows the combination of connections described above. 10 Fig. 16 shows one example in which the four power routers 100-400 are interconnected. Since all of the connection relations have been described above, each connection partner will not be described in detail. It would be understood, however, that all of the connection relations are permitted. 15 [0068]
Now, the connection line which connects the power router and the connection partner will be additionally described.
When the connection line that connects power routers is called a power-transmission line, the power-transmission line may be a part of the 20 utility grid or may be separated from the utility grid.
(In Fig. 16, the power-transmission line which is a part of the utility grid is denoted by the symbol 71A and the power-transmission line separated from the utility grid is denoted by the symbol 71B.)
In summary, a plurality of power routers may be connected to the 25 utility grid. In this way, by connecting two or more power routers
through the utility grid, power interchange can be performed among the plurality of power routers through the utility grid, and the utility grid can adjust the excessive power or the insufficient power to be interchanged. Alternatively, two or more power routers may be connected to each other 30 without the intervention of the utility grid.
Further, when the connection line that connects the power router and the load (or the distributed power supply) is called a distribution line 72, the distribution line 72 is separated from the utility grid 11. In summary, the distribution line 72 that connects the power router and the

34 load (or distribute^ power supply) is not connected to the utility grid 11.
[0069]
Further, as shown in Fig. 17, the power routers 100-400 may be
connected like a bus connection.
5 While a description of the operation mode of each leg is omitted, it
is needless to say that the operation mode of'each leg needs to be
appropriately selected in consideration of the direction of power
interchange and the connection restrictions described above.
As a matter of course, the utility grid 1 1 may be replaced by a 0 distributed power supply such as a power generation facility or a storage
battery in Fig. 17. That is, the plurality of power routers may be
connected to the distributed power supply by a bus.
[0070]
Further, the example shown in Fig. 18 is an example of the 5 connection form in which the two power routers 100 and 200 are
connected to the utility grid 11.
In Fig. 18, the utility grid 11 may be replaced by a distributed
power supply.
[0071]
0 As described above, the connection partner of the power router may
be a utility grid, a distributed power supply including a storage battery or
a power generation facility, or another power router. In this
specification and claims, the above are collectively called a power
system. 5 [0072]
With the power router, it is possible to build a power network
system in which the power cells are asynchronously interconnected.
According to the connection restrictions described in this exemplary
embodiment, legs can be connected to each other so that the roles of the 0 legs do not conflict with each other. It is therefore possible to extend
the power network system and to operate the whole system in a stable
manner.
[0073]
As described above, in the above-described power network system

35 using the p_o_wer routers 100 and the like, power supplied from a plurality
of power supply sources can be mixed through the DC bus provided in
each of the power routers. Further, power can be output from the leg
connected to the DC bus to the power supply destination. Therefore,
5 when received power is simply measured in the leg that externally outputs
power in the power router, the mixed power itself is measured.
Accordingly, it is impossible to identify (i.e., determine) the rate of
power supplied from each power supply source. Therefore, a power
network system, a power identification method, and a power router for
10 identifying (i.e., determining) a breakdown of power supply sources (i.e., identifying each of the power supply sources) even when power output from a plurality of power supply sources is mixed and received in the mixed state (hereinafter referred to as a "power identification technique") are explained hereinafter.
1 5 [0074]

In Example 1 of the power identification technique, an example in which a breakdown of power is identified (i.e., each of power supply sources is identified) in a case where power supplied from a plurality of
20 power grids is transmitted to one place through a plurality of power
routers is explained. Note that in Example 1 of the power identification technique, losses in power that occur during the power transmission are ignored. Further, the above-described "leg" is called "input/output terminal" or "input/output end part" in the following explanation.
25 [0075]
Fig. 19 is a block diagram showing a configuration of a power network system 10A according to Example 1 of the power identification technique. In the power network system 1.0A, a power router 100A, a power router 200A, and a central control device 52 are connected to each
3 0 other through a communication network 51. The power router 100A is connected between a utility grid 11 and the power router 200A in such a manner that power can be transmitted between the utility grid 11 and the power router 200A. Further, the power router 200A is connected with the power router 100A, a storage battery 35, and a load 30 in such a

36 manner that power can be transmitted among the power router 100A, the
storage battery 35, and the load 30. Therefore, when power is
transmitted from the utility grid 11 to the load 30, it is transmitted
through the power routers 100A and 200A, which are connected in a
5 multi-stage configuration. The power routers 100A and 200A belong to mutually different power cells (not shown) and connect their respective power cells to external power systems in an asynchronous manner. Note that the utility grid 11, the load 30, the storage battery 35, and the communication network 51 are similar to those explained above. Further,
0 the connection destination ofthe power router 100A or 200A in Fig. 19 is merely an example and it is not limited to this example. [0076]
The power router 100A includes a DC bus 101A, an input/output terminal 110A, an input/output terminal 120A, and a control unit 190A.
5 The input/output terminal 110A is connected to the utility grid 11 and the input/output terminal 120A is connected to an input/output terminal 210A ofthe power router 200A. Further, the power router 200A includes a DC bus 201A, an input/output terminal 210A, an input/output terminal 220A, an input/output terminal 230A, and a control unit 290A. The
0 input/output terminal 210A is connected to the input/output terminal 120A and the input/output terminal 220A is connected to the storage battery 35. Further, the input/output terminal 230A is connected to the load 30. Each ofthe input/output terminals 110A, 120A, 210A, 220A and 230A may have a configuration corresponding to the above-described
5 leg. Note that in Example 1 ofthe power identification technique, each ofthe input/output terminals 110A, 210A and 220A has to be capable of at least receiving power from a connection destination and outputting the received power to the DC bus 101A or 201A. Further, each ofthe input/output terminals 120A and 230A has to be capable of at least
0 receiving power from the DC bus 101A or 201A and outputting the received power to a connection destination. Similarly to the previously-described DC bus, each ofthe DC buses 101A and 201A is maintained at a predetermined rated voltage. The control unit 190A performs various kinds of control for the input/output terminals 1 10A and

37
120A including the control of the operating mode. Similarly, the control
unit 290A performs various kinds of control for the input/output
terminals 210A, 220A and 230A including the control of the operating
mode. Note that each of the control units 190A and 290A also has
5 functions similar to those of the control unit 190 shown in Fig. 1.
[0077]
Fig. 20 is a block diagram showing a configuration of the central
control device 52 according to Example 1 of the power identification
technique. The central control device 52 is an information processing
1 0 device that manages the power routers 100A and 200B and so on. The
central control device 52 includes a CPU (Central Processing Unit) 521, a memory 522, a communication unit 523, and a hard disk drive 524. [0078]
The hard disk drive 524 is a nonvolatile storage device. The hard
1 5 disk drive 524 stores an OS (not shown), a power transmission control program 5241, input/output terminal setting information 5242, power transmission route information 5243, a measurement tag 5244, a power tag 5245, and so on. Note that the power transmission control program 5241 is a computer program in which a power tag generation process (e.g.,
20 a process shown in Fig. 27, which is described later) and so on according to Example 1 of the power identification technique are implemented. [0079]
The input/ouLput terminal setting information 5242 is information in which a start time, an end time, active power, and so on of an input or
25 an output in each input/output terminal for the transmission of a
predetermined amount of power from a given transmission source to a given transmission destination are defined in advance. The power transmission route information 5243 is information in which a power transmission route with a connection relation of each input/output
3 0 terminal for the transmission of a predetermined amount of power from a given transmission source to a given transmission destination defined therein is defined. [0080]
The measurement tag 5244 is information including a measurement

38 value for received power measuredjn each input/output terminal, a
measurement time period, and identification information of an
input/output terminal part where the measurement is carried out
(hereinafter called "measured input/output terminal part"). The
5 measurement tag 5244 includes, for example, a measurement tag ID, a
power router ID, an input/output terminal ID, an input/output, a
measurement start time, an end time, measurement power information
(e.g., power [W] and energy (i.e., electric energy) [kWh]), and so on.
However, it is not limited to the aforementioned information items.
10 [0081]
The power tag 5245 is information that is obtained by combining additional information related to a transmission source for an input/output terminal part(s) included in the measurement tag with information in that measurement tag. The power tag 5245 includes, for
1 5 example, a power tag ID, a power router ID, an input/output terminal ID, an input/output, a date, a time period, a transmission source, breakdown power information (e.g., power [W] and energy [kWh]), and so on. However, it is not limited to the aforementioned information items. Therefore, when power from a plurality of transmission sources are mixed
20 with each other, the power tag 5245 is generated for each transmission source even if it is for the same input/output terminal and the same time period. [0082]
The CPU 521 controls various processes in the central control
25 device 52, access to the memory 522, the communication unit 523, and the hard disk drive 524, and so on. The communication unit 523 communicates with external entities including the power routers 100A and 200B and so on. [0083]
3 0 In the central control device 52, the CPU 521 reads the OS, the
power transmission control program 5241, or the like stored in the memory 522 or the hard disk drive 524, and executes the read program or the like. In this way, the central control device 52 can carry out a power tag generation process and so on.

39
[0084]
Here, the generation of power information that is performed when a
predetermined amount of power is transmitted from a given transmission
source to a given transmission destination in the power network system
5 10A is explained hereinafter. Fig. 21 shows an example of power
transmission according to Example 1 of the power identification
technique. That is, Fig. 21 shows a case where power from the utility
grid 1 1 and that from the storage battery 35 are mixed with each other and
the mixed power is transmitted to the load 30. Specifically, power of "7
10 kWh" is input from the utility grid 11 to the input/output terminal 110A of the power router 100A. Then, the power of "7 kWh" is fed from the input/output terminal 110A to the input/output terminal 120A through a route RT1; from the input/output terminal 120A to the input/output terminal 210A through a route RT2; and from the input/output terminal
1 5 210A to the input/output terminal 230A through a route RT3. Meanwhile, power of "3 kWh" is input from the storage battery 35 to the input/output terminal 220A of the power router 200A; and from the input/output terminal 220A to the input/output terminal 230A through a route RT4. Therefore, as a result, power of "10 kwh" is transmitted from the
20 input/output terminal 230A to the load 30. [0085]
Fig. 22 is a sequence diagram of a power transmission process according to Example 1 of the power identification technique. Firstly, the central control device 52 sets input/output terminals and determines
25 power transmission routes (SI). For example, the central control device 52 receives a request for power transmission shown in Fig. 21 from an external entity. Then, the central control device 52 sets input/output terminals and determines power transmission routes in order to carry out the power transmission according to this request.
30 [0086]
Note that Fig. 23 shows an example of an input/output terminal setting management table according to Example 1 of the power identification technique. For example, the central control device 52 makes settings ST1 to ST5 as shown in Fig. 23 and stores the settings into

40 the hard disk drive 52_4 as input/output terminal setting information 5242.
[0087]
Further, Fig. 24 shows an example of power transmission route
information according to Example 1 of the power identification technique.
5 Fig. 24 shows an example in which identification information of
input/output terminals that become transmission sources are associated
with that of input/output terminals that become transmission destinations
in a one-to-one relation irrespective of whether they are located inside
power routers or not, and those associations are defined as their
1 0 respective routes. For example, the input/output terminal 230A is the
transmission destination of both of the routes RT3 and RT4. Therefore, this indicates that power from the input/output terminals 210A and 220A are mixed and the mixed power is received in the input/output terminal 230A. Note that the expressions of power transmission route
1 5 information are not limited to the above-shown example. The central
control device 52 defines, for example, the routes RT1 to RT4 as shown in Fig. 24.and stores them into the hard disk drive 524 as power transmission route information 5243. [0088]
20 Next, the central control device 52 instructs the power routers
100A and 200A to perform power transmission settings and power measurement (S12A and S12B). That is, the central control device 52 transmits the above-described instruction to the power routers 100A and 200A through the communication network 51. As a result, each of the
25 control units 190A and 290A of the power routers 100A and 200A,
respectively, instructs its internal input/output terminal(s) to perform power transmission and measure power received in each input/output terminal. For example, each of the control units 190A and 290A may set a measurement interval.
30 [0089]
Then, each input/output terminal measures its received power (S13A and S13B). Note that each input/output terminal measures energy. Alternatively, each input/output terminal may measure a quantity other than the energy. After that, each input/output terminal notifies the

41 control unit o_f_the power router of the measured measurement value.
Then, each control unit generates a measurement tag including the
notified measurement value, a measurement time period, and
identification information of the measured input/output terminal(s)
5 (S14A and S14B) and transmits the generated measurement tag to the
central control device 52 (S15A and S15B). Fig. 25 shows an example of
measurement tags according to Example 1 of the power identification
technique.
[0090]
10 After that, the central control device 52 generates a power tag in
the power transmission based on the measurement tags received from the control unit of each power router located on the power transmission route (S16). That is, the central control device 52 generates, as power information, a power tag including information about the power
1 5 transmission sources for the input/output terminal parts included in the received measurement tags by using those measurement tags. Note that examples of the additional information include information that cannot be obtained by the measurement alone, such as the power selling price of power in its power transmission source, a CO2 emission coefficient, the
20 type of power generation (nuclear power, thermal power, pumping-up power, wind power, and so on), and a contract ID related to the power transmission. However, the additional information is not limited to the aforementioned information items. Fig. 26 shows an example of power tags according to Example 1 of the power identification technique.
25 [0091]
Fig. 27 is a flowchart showing a power tag generation process flow according to Example 1 of the power identification technique. Firstly, the central control device 52 determines whether or not there is any unselected input/output terminal (S21). That is, the central control
3 0 device 52 determines whether or not there is an input/output terminal for which a power tag should be generated. Specifically, the central control device 52 determines, in a given time period in the power transmission, whether or not there is a measurement tag that corresponds to one of the input/output terminals located on the power transmission route but has

42 not yet been processed.
[0092]
When there is an unselected input/output terminal, the central
control device 52 selects the unselected input/output terminal (S22).
5 Then, the central control device 52 identifies the power transmission
source of power received in each input/output terminal part in each power
router located on the power transmission route based on the input/output
terminal setting information 5242 (S23). It should be noted that when
power received in the input/output terminal is mixed power, a plurality of
1 0 power transmission sources are identified. Next, the central control device 52 generates a power tag for each of the identified power transmission sources by using the measurement tag (S24). That is, the central control device 52 generates a power tag by combining the above-described additional information with the measurement tag and
1 5 stores the generated power tag into the hard disk drive 524. [0093]
After that, the central control device 52 repeats the processes in the steps S21 to S24 as long as there is an unselected input/output terminal. When there is no input/output terminal for which a power tag
20 should be generated in the step S21, the power tag generation process is f i n i s h e d. [0094]
In this way, by using power tags, it is possible to recognize a breakdown of power (i.e., identify each of a plurality of power supply
25 sources of power) received in a given input/output terminal based on a respective power tag. For example, based on a measurement tag MT5, "10.0 kWh" is received in total in the input/output terminal 230A (Fig. 25). Further, as its breakdown, it can be recognized that the power transmission source of "7.0 kWh" is the input/output terminal 210A and
3 0 the power transmission source of "3 kWh" is the input/output terminal 220A (Fig. 26). [0095]
Note that in Example 1 of the power identification technique, it is also possible to recognize a breakdown of power by using power

43 information other than the power tags. A_s a precondition, assume that:
one of the input/output terminal parts of a first power router (e.g., power
router 100A) among a plurality of power routers is a first power
transmission source (e.g., input/output terminal 110A connected to the
5 utility grid 11); one of the input/output terminal parts of a second power
router (e.g., power router 200A) is a second power transmission source
(e.g., input/output terminal 220A); another one of the input/output
terminal parts of the second power router is a power transmission
destination (e.g., input/output terminal 230A connected to the load 30),
1 0 and an input/output terminal part(s) that is different from the second
power transmission source and the power transmission destination and
receives power from the first power transmission source is an
intermediate input/output terminal(s) (or first input/output terminal part)
(e.g., input/output terminal 210A). Further, it is assumed that a
1 5 predetermined amount of power is transmitted to the input/output
terminal part at the power transmission destination through the first input/output terminal part, the input/output terminal part at the second power transmission source, and the DC bus. Note that in the example shown in Fig. 19, the supply source of the power transmitted from the 20 second power transmission source may be a supplementary power supply source for adjusting for the excess/deficiency of the power transmitted through the first power transmission source in the transmission of the predetermined amount of power. [0096]
2 5 Note that the power information about power received in the power
transmission destination may include at least identification information of the first power transmission source and an intermediate measurement value, i.e., a measurement value of power received in the intermediate input/output terminal part in a predetermined time period. Note that the
3 0 identification information of the first power transmission source is
information for uniquely identifying each input/output terminal part in all the power routers in the power network system 10A. For example, the identification information of the first power transmission source may be expressed by a combination of a power router ID (e.g., an ID of the power

44 router 1 00 A) and a leg ID (e.g., an ID ofthe input/output terminal 110A).
Note that the intermediate input/output terminal part(s) may be an
input/output terminal part(s) in each power router through which the
predetermined amount of power is transmitted. For example, the
5 intermediate input/output terminal part(s) is the input/output terminals defined in the routes RT1 to RT5. Further, the intermediate input/output terminal part is an input/output terminal part that receives the power that is transmitted from the first power transmission source but has not yet been: mixed with the power transmitted from the second power
0 transmission source. For example, the power received in the
input/output terminal 120A or the input/output terminal 210A is the power of "7 kWh" transmitted from the utility grid 11, which is the first power transmission source. Further, it is the power that has not mixed with the power of "3 kWh" transmitted from the storage battery 35, which
5 is the second power transmission source. [0097]
Fig. 28 shows a structure example of power information according to Example 1 ofthe power identification technique. That is, the power information may include at least an ID ofthe power transmission source
0 (e.g., the above-described "power router ID + leg ID") and an
intermediate measurement value of power measured in the intermediate input/output terminal part in a predetermined time period. Note that when the predetermined time period is an arbitrary time period, the power information preferably includes the measurement time period itself. On
5 the other hand, when the predetermined time period is a time period that is defined in advance, the power information does not necessarily have to include the measurement time period itself. Fig. 29 is a flowchart showing a power information generation process flow according to Example 1 of the power identification technique. Firstly, the
0 intermediate input/output terminal part measures power received in the intermediate input/output terminal part itself (S3 1). Then, for example, the intermediate input/output terminal part transmits the intermediate measurement value to the central control device. Next, the central control device identifies the (first) power transmission source of the

45
intermediate input/output terminal part based on power transmission
route information (S32). After that, the central control device generates
power information including the intermediate measurement value and
identification information of the identified first power transmission
5 source (S33).
[0098]
Therefore, by checking the power information, it is possible to
recognize that, of the whole power indicated by the measurement value
measured in the power transmission destination, at least power indicated
10 by the intermediate measurement value has been transmitted from at least one of the plurality of power transmission sources (because losses in the power are ignored in this example). Therefore, it can also be recognized that the power measured at the power transmission destination includes power that has been transmitted from other(s) of the plurality of power
1 5 transmission sources. [0099]
Further, the intermediate input/output terminal part is preferably an input/output terminal part that is located in a power router in which the power transmission destination is located and receives power from the
20 other power router(s). For example, the intermediate input/output terminal part is preferably an input/output terminal 210B.. This configuration improves the accuracy of the recognition (i.e., the identification) because the intermediate measurement value is a measurement value immediately prior to the mixing of the power.
25 [0100]

In Example 2 of the power identification technique, Example 1 of the power identification technique is modified so that a breakdown of power can be recognized (i.e., each power supply source is identified)
3 0 even when losses in the power that occur during the power transmission are taken into account. Fig. 30 is a block diagram showing a configuration of a power network system 10B according to Example 2 of the power identification technique. In the power network system 10B, a power router 100B, a power router 200B, and a central control device 52B

46 are connected to each other through a communication network 5 1. The
power router 100B is connected with a utility grid 11, a solar pane! 33,
and a power router 200B in such a manner that power can be transmitted
among the utility grid 11, the solar panel 33, and the power router 200B.
5 Further, the power router 200B is connected with the power router 100B,
a storage battery 35, and a load 30 in such a manner that power can be
transmitted among the power router 100B, the storage battery 35, and the
load 30. Further, the connection destination of the power router 100B or
200B in Fig. 30 is merely an example and it is not limited to this example.
10 [0101]
The power router 100B includes a DC bus 101B, input/output terminals 110B, 120B, 130B and 140B, and a control unit 190B. The input/output terminal HOB is connected to the solar panel 33 and the input/output terminal 120B is connected to the utility grid 11. Further,
15 the input/output terminal 140B is connected to an input/output terminal 210B of the power router 200B. Note that the input/output terminal 130B may be connected to an external entity. [0102]
The power router 200B includes a DC bus 201B, input/output
20 terminals 210B, 220B, 230B and 240B, and a control unit 290B. The input/output terminal 210B is connected to the input/output terminal 1406 and the input/output terminal 220B is connected to the storage battery 35. Further, the input/output terminal 230B is connected to the load 30. Note that the input/output terminal 240B may be connected to
2 5 an external entity. [0103]
Note that the input/output terminals 120B and 220B are operated and controlled in the above-described master mode. Therefore, the input/output terminal 120B transmits/receives power to/from the utility
30 grid 11 in order to maintain the DC bus 101B at its rated voltage. Similarly, the input/output terminal 220B transmits/receives power to/from the storage battery 35. For example, when power is transmitted from the solar panel 33 to the load 30 through the power routers 100B and 200B, there is a possibility that sufficient power could not be output from

47 the input/output_terminal MOB due to power losses occurring on the
power transmission route even when the originally-determined power
(e.g., power specified in a power buying contract) is received from the
solar panel 33 in the input/output terminal 110B. In such cases, the
5 input/output terminal 120B acquires power equivalent to the shortage
from the utility grid 11 and supplies the acquired power to the DC bus
101B. Similarly, the input/output terminal 220B acquires power
equivalent to the shortage from the storage battery 35 and supplies the
acquired power to the DC bus 201B.
10 [0104]
Therefore, when the solar panel 33 is the powrer supply source to be purchased in a power buying contract, the utility grid 11 and the storage battery 35 can serve as supplementary power supply sources. That is, although the utility grid 11 and the storage battery 35 are not entities
15 from which power is directly bought, they can serve as entities which supply power depending on the power loss situation and for which payment is made for the supplied power. [0105]
For the other configuration, each component/structure of the power
20 routers 100B and 200B may have a function similar to that of the power routers 100A and 100B shown in Fig. 19. [0106]
Fig, 31 is a block diagram showing a configuration of the central control device 52B according to the Example 2 of the power identification
25 technique. A hard disk drive 524 of the central control device 52B stores power transmission/reception transaction contract information 5246 and correspondence relation management information 5247 in addition to the information items shown in Fig. 20. Note that the power transmission/reception transaction contract information 5246 is contract
3 0 information for transmitting a predetermined amount of power from a first power transmission source (e.g., the input/output terminal 110B connected to the solar panel 33) to a power transmission destination (e.g., the input/output terminal 230B connected to the load 30). The power transmission/reception transaction contract information 5246 includes,

48 for example, a contract ID, a power transmitter ID, a power receiver ID, a
date, a time period, a contract time, a transaction energy, a price, a CO2
emission coefficient, the type of power generation, and so on. However,
the power transmission/reception transaction contract information 5246
5 does not need to include all of them and may include other information
items. Further, the correspondence relation management information
5247 is a table for managing associations between contract IDs and
setting IDs. Note that the way of managing the association between the
power transmission/reception transaction contract information 5246 and
1 0 the correspondence relation management information 5247 is not limited
to the above-described table,
[0107]
Further, the central control device 52B may function as a power
transaction device in addition to having functions similar to those of the
1 5 central control device 52 shown in Fig. 20. The power transaction
device is, for example, an information system that supports a power transaction contract between a power vendor and a power buyer. Note that the power transaction device may be implemented by a computer independent of the central control device 52B. In that case, the power 20 transaction device may be connected to another communication network connected to the communication network 51 or the central control device 52B. [0108]
Further, the central control device 52B sets power transmission
2 5 route information 5243 by defining a connection relation of each
input/output terminal part based on the power transmission/reception transaction contract information 5246. Note that the power transmission route information 5243 does not need to include the connection relation of each input/output terminal part but does need to specify at least the
3 0 definitions of input/output terminals for generating power information.
[0109]
Note that in the power router 100B according to the Example 2 of the power identification technique, power can be supplied from external entities through a plurality of input/output terminals, and through the DC

49 bus 10 IB, power is output to external entities from a plurality of
input/output terminals. In such cases, there are several methods for
carrying out the distribution of power from the DC bus 101B to a plurality
of input/output terminals. Examples of those methods include ones
5 shown in Figs. 32 and 33. [0110]
Fig. 32 shows an example of an association between input power and output power according to the Example 2 of the power identification technique. In this example, power is supplied from each of two
0 terminals and the supplied power is distributed to other two terminals in the same ratio as the ratio at which the power is supplied. Fig. 33 shows another example of an association between input power and output power according to the Example 2 of the power identification technique. In this example, power is also supplied from each of two terminals and the
5 supplied power is distributed to other terminals in such a manner that the supply source terminals are associated with the output destination terminals in a one-to-one relation. Note the above-described power distribution methods are also applied to the power router 200B and the power distribution methods are not limited to the above-described
0 methods. [0111]
Here, the generation of power information in a case where a power interchange is performed when a predetermined amount of power is transmitted from a given power transmission source to a given power
5 transmission destination in the power network system 10B is explained hereinafter. Fig. 34 shows an example of a power interchange according to the Example 2 of the power identification technique. In this example, it is assumed that power of "10 kWh" is transmitted from a solar panel 33 to a load 30 in a predetermined time period according to a power
0 transaction contract. [0112]
For example, the above-described power transaction device transmits information about a power transaction contract concluded between a power vendor and a power buyer and a power interchange

50 ___ request to the central control device 5 2B based on that information.
Then, the central control device 52B stores the received information into
the hard disk drive 524 as power transmission/reception transaction
contract information 5246.
5 [0113]
Fig. 35 shows an example of a power transmission/reception
transaction contract information management table according to the
Example 2 of the power identification technique. For example, a
contract C3 in Fig. 35 corresponds to the above-described contract.
10 Note that as shown in Fig. 35, a plurality of power transaction contracts are made, and their dates and time periods can overlap each other. Note that the information held by the power transmission/reception transaction contract information management table is not limited to the above-described information items.
15 [0114]
After that, the central control device 52B sets input/output terminals and determines power transmission routes according to the sequence shown in Fig. 22 (Sll) and instructs the power routers 100B and 200B to perform power transmission settings and power measurement
20 (S12A and S12B). [0115]
Note that Fig. 36 shows an example of an input/output terminal setting management table according to the Example 2 of the power identification technique. Note that input/output terminal setting
25 management table may include other setting information such as
active/reactive power ramp rate in addition to the information items shown in Fig. 36. Note that it is assumed that the central control device 52B makes settings ST1 to ST4 for directly carrying out the contact C3. That is, no setting for the input/output terminals 120B and 220B
3 0 connected to the utility grid 1 1 and the storage battery 35, which are supplementary power supply sources, is made. [0116]
Further, Fig. 37 shows an example of a correspondence table between power transmission/reception contract information and an

51 input/output terminal setting according to the Example 2 of the power
identification technique. In this table, only the setting ST1, which is
associated with the contract C3, among the settings ST1 to ST4 is shown
because the following explanation is given for the contract C3. Since
5 only the setting for the input/output terminal directly connected to the
system or the power supply is managed (or stored), there is no need to
manage (or store) all the correspondence relations, thus enabling the data
capacity to be efficiently used.
[01F7]
1 0 Further, when the central control device 52B determines power
transmission routes, the central control device 52B determines them while
including power transmission routes for supplementary power for
carrying out the contract C3. Fig. 38 shows an example of power
transmission route information according to the Example 2 of the power
1 5 identification technique. For example, routs RT2 and RT5 correspond to
the power transmission routes for supplementary power for carrying out
the contract C3.
[0118]
After that, the transmission of power is actually started. Each 20 input/output terminal measures power every time the power transmission is started (S13A and S13B). Further, each control unit generates a measurement tag (S14A and S14B) and transmits the generated measurement tag to the central control device 52B (S15A and S15B). After that, the central control device 52B performs a power tag generation
2 5 process (S 1 6).
[0119]
However, it is assumed in Example 2 of the power identification technique that power losses occur in various places on the power transmission routes as shown in Fig. 34. A power interchange flow in
3 0 this example is explained hereinafter.

WE CLAIMS:-
1. A power network system comprising a plurality of power cells each comprising a power router for asynchronous connection to a power grid, wherein
the power router comprises:
a DC bus maintained at a predetermined rated voltage;
a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and
control means for controlling the plurality of input/output end parts,
at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts,
some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends,
each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources,
some of the plurality of input/output end parts included in the second power router are used as a plurality of power receiving ends,
each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends,
the power network system comprises a power adjustment apparatus connected to the first and second power routers through a communication network,
the power adjustment apparatus comprises power adjustment means for adjusting the supply power according to a power request value

97
requested in each of the plurality of power receiving ends, and
the power adjustment means:
acquires, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining a power transmitting end for which an adjustment of the supply power to be supplied to each of the plurality of power receiving ends should be prioritized; and
determines a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and the priority defined in the power supply priority information.
2. The power network system according to Claim 1, wherein the power adjustment means adjusts the supply power in the determined power transmitting end so as to bring a value of the received power in each of the power receiving ends closer to the power request value.
3. The power network system according to Claim 1 or 2, wherein the power adjustment means:
adjusts, for each of the plurality of power receiving ends, the supply power of the power transmitting end having the highest priority, which is determined based on the received power information and the power supply priority information; and
determines, after the adjustment, the power transmitting end having a next highest priority as the power transmitting end for which the supply power is adjusted based on the received power information and the power supply priority information.
4. The power network system according to any one of Claims 1 to 3, wherein
the received power information further includes attribute

98 information of a supply source that supplies the supply power for each of
the plurality of power transmitting ends,
in the power supply priority information, a priority of the attribute information is defined as a priority for determining the power transmitting end for which the adjustment should be prioritized for each of the plurality of power receiving ends, and
the power adjustment means:
refers to the power supply priority information and specifies the attribute information corresponding to a predetermined priority; and
refers to the received power information and determines the power transmitting end corresponding to the specified attribute information.
5. The power network system according to Claim 4, wherein the attribute information includes, for each of the plurality of
power transmitting ends, a plurality of attribute types and attribute
values corresponding to the respective attribute types,
the power supply priority information includes information in a
case where different priorities of the attribute types or different
priorities of the attribute values are defined among the plurality of power
receiving ends.
6. The power network system according to any one of Claims 1 to 5, wherein
the power adjustment means:
calculates, for each of the plurality of power receiving ends, a difference between a current received power value and the power request value;
selects a priority to be processed in a descending order from the highest priority to the lowest priority based on the power supply priority information;
performs a determination process every time the priority to be processed is selected until the difference is cancelled out; and
adjusts the supply power in each of the plurality of power transmitting ends based on an adjustment value of the supply power

99 determined by the determination process, and
the determination process comprises:
specifying the power transmitting end corresponding to the priority to be processed among the power transmitting ends included in the received power information for each of the plurality of power receiving ends;
specifying a value of the supply power supplied from the specified power transmitting end included in the current received power value based on the received power information and setting this specified supply power value as an increase/decrease request value for the specified power transmitting end;
calculating a total increase/decrease request value by summing up the increase/decrease request value sets for each of the plurality of power transmitting ends;
determining whether or not the total value of the current supply power value in each of the plurality of power transmitting ends and the total increase/decrease request value is within a predetermined threshold range;
determining, when the total value is determined to be within the threshold range, the increase/decrease request value set for each of the plurality of power transmitting ends as the adjustment value of the supply power for the power transmitting end for which the determination is made and
correcting, when the total value is determined to be outside the threshold range, the increase/decrease request value set for each of the plurality of power transmitting ends so that it falls within the threshold range and determining the corrected increase/decrease request value as the adjustment value of the supply power for the power transmitting end for which the determination is made.
7. The power network system according to any one of Claims 1 to 6, wherein when the power adjustment means externally receives the power request value, the power adjustment means calculates a difference between the received power request value and the current received power

100 value, and when the difference is equal to or greater than a predetermined
value, adjusts the supply power.
8. The power network system according to any one of Claims 1 to 6, wherein the power adjustment means measures the current received power value in each of the plurality of power receiving ends at a predetermined interval, and when the difference between the measured received power value and the power request value is equal to or greater than a predetermined value, adjusts the supply power.
9. The power network system according to any one of Claims 1 to 8, wherein the power adjustment apparatus further comprises storage means for storing the power supply priority information.
10. A power adjustment apparatus connected to a power router through a communication network, the power router comprising:
a DC bus maintained at a predetermined rated voltage;
a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and
control means for controlling the plurality of input/output end parts, wherein
at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts,
some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends,
each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources,
some of the plurality of input/output end parts included in the

101 second power router are used as a plurality of power receiving ends,
each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends,
the power adjustment apparatus comprises power adjustment means for adjusting the supply power according to a power request value requested in each of the plurality of power receiving ends, and
the power adjustment means:
acquires, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining the power transmitting end for which an adjustment of the supply power to be supplied to each of the plurality of power receiving ends should be prioritized; and
determines a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and the priority defined in the power supply priority information.
11. A power adjustment method using a power router and a power adjustment apparatus connected to the power router through a communication network, the power router comprising:
a DC bus maintained at a predetermined rated voltage;
a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and
control means for controlling the plurality of input/output end parts, wherein

102 at least first and second power routers among the plurality of
power routers are connected to each other by respective input/output end
parts, and
when:
some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends;
each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources;
some of the plurality of input/output end parts included in the second power router are used as a plurality of power receiving ends; and
each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends,
the power adjustment apparatus:
acquires, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining the power transmitting end for which an adjustment of the supply power to be supplied to each of the plurality of power receiving ends should be prioritized;
determines a power transmitting end for which the supply power is adjusted from among the plurality of power transmitting ends based on the received power information and the priority defined in the power supply priority information;
determines an adjustment value of supply power at the determined power transmitting end; and
adjusts the supply power in each of the plurality of power transmitting ends based on the determined adjustment value.
12. A non-transitory computer readable medium storing a power

103 adjustment program for causing a computer connected to a power router
through a communication network to execute a power adjustment process,
the power router comprising:
a DC bus maintained at a predetermined rated voltage;
a plurality of input/output end parts, one of connection ends of each of the input/output end parts being connected to the DC bus and the other of the connection ends serving as an external connection terminal and being connected to an external connection partner, each of the input/output end parts being configured to convert power between the one connection end and the other connection end; and
control means for controlling the plurality of input/output end parts, wherein
at least first and second power routers among the plurality of power routers are connected to each other by respective input/output end parts, and
when:
some of the plurality of input/output end parts included in the first power router are used as a plurality of power transmitting ends;
each of the plurality of power transmitting ends supplies supply power to the second power router, the supply power being supplied from one of a plurality of power supply sources;
some of the plurality of input/output end parts included in the second power router are used as a plurality of power receiving ends; and
each of the plurality of power receiving ends receives supply power through the DC bus and supplies the received power to one of a plurality of power demanders, the supply power being supplied from each of the plurality of power transmitting ends,
the power adjustment program causes the computer to execute:
a process of acquiring, for each of the plurality of power receiving ends, received power information including identification information of each of the plurality of power transmitting ends and a value of supply power supplied from each of the plurality of power transmitting ends, and power supply priority information defining a priority for determining the power transmitting end for which an adjustment of the supply power to be

104 supplied to each of_the plurality of power receiving ends should be
prioritized;
a process of determining a power transmitting end for which the
supply power is adjusted from among the plurality of power transmitting
ends based on the received power information and.the priority defined in
the power supply priority information;
a process of determining an adjustment value of supply power at
the determined power transmitting end; and
h a process of adjusting the supply power in each of the plurality of
power transmitting ends based on the determined adjustment value.