Field of the Invention
The present invention relates to a power distribution
system for a building such as a public housing or a rental
housing and a protection method for a main line thereof.
Background of the Invention
As described in Patent Documents 1 and 2, in a
building such as a mansion or a tenant building, an electric
power is distributed to each dwelling unit or each tenant
via a main line which is wired to pass through each floor.
The main line is branched into electric power distribution
lines in each floor, so that the electric power can be
distributed to each dwelling unit or each tenant via the
electric power distribution lines.
Patent Document 1: Japanese Patent Application
Publication No. 2008-178275
Patent Document 2: Japanese Patent Application
Publication No. 2009-124846
In this power distribution system for a building, when
a power consumption of the entire building is increased, a
current flowing through the main line may exceed a rated
current. If the current flowing through the main line
exceeds the rated current, a part of breakers provided at
the building is shut down to stop a supply of the electric
power, so that the main line is protected from overcurrent.
However, until the main line is recovered, the electricity
cannot be used at the location where the supply of electric
power is stopped, which causes inconvenience to residents.
Summary of the Invention
In view of the above, the present invention provides a
power distribution system for a building and a protection
method for a main line thereof, capable of properly
preventing an overcurrent in a main line-without stopping a
supply of an electric power.
In accordance with an aspect of the present invention,
there is provided a power distribution system for a
building, including: an electric current sensor for
detecting a current value of an electric current flowing
from a commercial AC power source through a main line in a
building; and a storage battery installed at the building.
When the current value detected by the1 electric current
sensor reaches a predetermined value, a supply of an
electric power to the building from the storage battery is
initiated.
The power distribution system further includes an
overcurrent protection unit. The building includes a
plurality of sections individually equipped with electric
power supply systems, and the overcurrent protection unit
protects the main line of the building from an overcurrent
by initiating the supply of the electric power from the
storage battery to the building when the current value
detected by the electric current sensor becomes equal to or
greater than a predetermined current value for the
initiation of main line protection.
In this configuration, when the current flowing from
the commercial AC power source to the main line becomes
equal to or greater than a main line protection initiation
current value, the main line protection control is
initiated, so that the supply of an electric power from the
storage battery installed at the building is initiated.
When the supply of the electric power from the storage
battery is initiated, a part of the electric power that has
been supplied entirely from the commercial power source is,
in turn, supplied from the storage battery, and the current
flowing from the commercial AC power source to the main line
is reduced. The reduced supply amount of the electric power
from the commercial AC power source can be compensated by
the supply amount of the electric power from the storage
battery.
Therefore, the total supply amount of electric power
after initiation of the protection control can be maintained
at the same level as that before the initiation of the
protection control. Accordingly, with such configuration,
the overcurrent of the main line can be properly protected
without stopping the supply of the electric power.
Further, the storage battery may be provided at a side
of the main line which is opposite to a side where the
commercial AC power source is provided, and the overcurrent
protection unit may initiate the supply of the electric
power from the storage battery to the building.
In this configuration, when the current flowing from
the commercial AC power source to the main line becomes
equal to or greater than the main line protection initiation
current value, the protection control of the main line is
initiated, so that the current flows to the main line from
the storage battery connected to the side of the main line
which is opposite to the side where the commercial AC power
source is provided.
When the supply of the electric power from the storage
battery is initiated, a part of the electric power that has
been supplied entirely from the commercial AC power source
is, in turn, supplied from the storage battery, and the
current flowing from the commercial AC power source to the
main line is reduced. The reduced supply amount of the
electric power from the commercial AC power source is
compensated by the supply amount of the electric power from
the storage battery, so that the total supply amount of
electric power after initiation of the protection control
can be maintained at the same level as that before the
initiation of the protection control. Hence, with such
configuration, the overcurrent of the main line can be
properly protected without stopping the supply of the
electric power.
Further, the storage battery may be provided at each
of the sections, and the overcurrent protection unit may
initiate the supply of the electric power from the storage
battery to the main line in the building.
In this configuration, when the current flowing from
the commercial AC power source to the - main line becomes
equal to or greater than the main line protection initiation
current value, the protection control of the main line is
initiated, and the supply of an electric power from the
storage battery installed at the dwelling unit or the tenant
in the building is initiated.
When the supply of the electric power from the storage
battery is initiated, a part of the electric power that has
been supplied entirely from the commercial AC power source
is, in turn, supplied from the storage battery, and the
current flowing from the commercial AC power source to the
main line is reduced. The reduced supply amount of the
electric power from the commercial AC power source is
compensated by the supply amount of the electric power from
the storage battery, so that the total supply amount of
electric power after initiation of the protection control
can be maintained at the same level as that before
initiation of the protection control. Hence, with such
configuration, the overcurrent of the main line can be
properly protected without stopping the supply of the
electric power.
Further, the power distribution system may further
include a storage battery current sensor for detecting a
current value of an electric current supplied from the
storage battery and a release unit for stopping the supply
of the electric power from the storage battery which is
carried out by the overcurrent protection unit when the sum
of the current values detected by the electric current
sensor and the storage battery current sensor becomes equal
to or lower than a predetermined current value for the
release of main line protection.
In this configuration, after the initiation of the
supply of the electric power from the storage battery, the
supply of the electric power from the storage battery to the
main line is stopped when the total current value of the
current supplied from the commercial AC power source and the
current supplied from the storage battery becomes equal to
or lower than the predetermined current value for the
release of main line protection. Therefore, the protection
control of the main line carried out by the supply of the
electric power from the storage battery can be released
after confirming that the supply of the electric power from
the commercial AC power source does not become excessive
even after stopping the supply of the electric power from
the storage battery. Further, in order to reliably prevent
the occurrence of the overcurrent after the release of the
protection control, it is preferable to set the current
value for the release of main line protection to be lower
than the current value for the initiation of main line
protection.
Further, the current value for the release of the main
line protection may be set to be different by a
predetermined constant value from the current value for the
initiation of the main line protection.
In this configuration, the main line protection
release current value is set to be different by a
predetermined constant value from the main line protection
initiation current value. Accordingly, the supply of the
electric power from the storage battery is not stopped
unless the total value of the current supplied from the
commercial AC power source and the current supplied from the
storage battery is sufficiently lower than the current value
for the initiation of main line protection. Hence, the
hunting of the protection control, i.e., the resumption of
the main line protection control immediately after the
release of the main line protection control, can be properly
prevented.
In accordance with another aspect of the present
invention, there is provided a method for protecting a main
line of a building from an overcurrent in a power
distribution system for distributing an electric power to
each floor of the building via the main line which is wired
to pass through each floor of the building, the method
including: detecting a current value of an electric current
flowing from a commercial power source through the main
line; and initiating a supply of an electric power to the
building from a storage battery installed at the building
when the detected current value becomes equal to or greater
than a predetermined current value for the initiation of
main line protection.
In this protection method, when the current flowing
from the commercial AC power source to the main line becomes
equal to or greater than the main line protection initiation
current value, the protection control of the main line is
performed, so that the supply of an electric power from the
storage battery installed at the building is initiated.
When the supply of the electric power from the storage
battery is initiated, a part of the electric power that has
been supplied entirely from the commercial AC power source
is supplied from the storage battery and, thus, the current
flowing from the commercial AC power source to the main line
is reduced. At this time, the reduced supply amount of the
electric power from the commercial AC power source is
compensated by the supply amount of the electric power from
the storage battery, so that the total supply amount of
electric power after initiation of the protection control
can be maintained at the same level as that before
initiation of the protection control. Hence, with such
protection method, the main line can be properly protected
from an overcurrent without stopping the supply of the
electric power.
Brief Description of the Drawings
The objects and features of the present invention will
become apparent from the following description of
embodiments, given in conjunction with the accompanying
drawings, in which:
Fig. 1 is a block diagram schematically showing an
entire configuration of a power distribution system in
accordance with an embodiment of the present invention;
Fig. 2 is a block diagram schematically showing a
configuration of a power supply system installed at each
dwelling unit of a residential complex in the embodiment of
the present invention;
Fig. 3 is a block diagram schematically showing a
configuration of a general control unit in the embodiment of
the present invention;
Fig. 4 is a block diagram schematically showing a
configuration of a storage battery control unit in the
embodiment of the present invention;
Fig. 5 is a block diagram schematically showing
configurations of an AC power distribution board and a home
control unit in the embodiment of the present invention; and
Fig. 6 is a flowchart showing a processing sequence of
the general control unit in a main line protection control
routine employed in the embodiment of the present invention.
Detailed Description of the Embodiments
Hereinafter, embodiments of the present invention will
be described with reference to the accompanying drawings
which form a part hereof. Throughout the drawings, like
reference numerals will be given to like parts, and
redundant description thereof will be omitted.
(First embodiment)
Hereinafter, a power distribution system for a
building and a protection method for a main line of the
power distribution system in accordance with a first
embodiment of the present invention will be described in
detail with reference to Figs. 1 to 6. In the following
description, the present invention is applied to a
residential complex having a plurality of dwelling units.
However, the present invention is not limited thereto, and
the residential complex may refer to, e.g., a building
having one or more floors equipped with respective power
supply systems, each floor having a plurality of sections.
Fig. 1 shows a schematic configuration of a power
distribution system for a building in accordance with the
first embodiment of the present invention.
In a residential complex 100 shown in Fig. 1, a main
line 50 is wired to pass through each floor thereof. The
main line 50 is branched into power distribution lines in
each floor, and the power distribution lines are connected
to AC power distribution boards 11 of dwelling units 101,
respectively. Further, a main line breaker 51 that
interrupts an electric current when the current flowing
through the main line 50 exceeds a rated current is
installed at an inlet portion where the main line 50 is
introduced to the building.
Moreover, a current sensor 52 for monitoring a value
of an electric current flowing from a commercial AC power
source to the main line 50 is provided at the inlet portion
of the main line 50. The detection signals of the current
sensors 52 are inputted to a general control unit 53 for
controlling an entire power distribution of the residential
complex 100.
Further, a storage battery 55 is connected to an
outlet portion (e.g., an uppermost portion in the present
embodiment) of the main line 50 via an AC/DC converter 54.
The charging and discharging of the storage battery 55 is
performed by controlling the AC/DC converter 54 by a storage
battery control unit 56.
Fig. 2 shows a schematic configuration of a power
supply system installed at each dwelling unit 101 of the
residential complex 100.
As shown in Fig. 2, each dwelling unit 101 of the
residential complex 100 is equipped with a power supply
system 1 for supplying an electric power to various kinds of
appliances such as a lighting device, an air conditioner, a
home appliance, an audiovisual device and the like. The
power supply system 1 supplies, as a power source, the
commercial AC power through the main line 50 to operate
various kinds of appliances. Further, the power supply
system 1 supplies, as a power source, an electric power
generated from a fuel cell 3 by using a reverse reaction of
electrolysis of water or an electric power generated from a
solar cell (not shown) to various kinds of appliances. The
power supply system 1 supplies the electric power not only
to a DC appliances 5 operated with DC power inputted thereto
but also to an AC appliances 6 operated with the AC power
inputted thereto.
The power supply system 1 includes a home control unit
7 and a DC power distribution board 8(having a DC breaker
installed therein). Further, the power supply system 1
includes a control unit 9 and a relay unit 10 for
controlling operations of the DC appliances 5 in each
dwelling unit.
The AC power distribution board 11 for distributing
the AC power is connected to the home control unit 7 via an
AC power line 12. The home control unit 7 is connected to
the commercial AC power source 2 via the AC power
distribution board 11 and also connected to the fuel cell 3
via a DC power line 13. The home control unit 7 acquires
the AC power through the AC power distribution board 11 and
a DC power from the fuel cell 3 and converts the acquired
power into a specified DC power as a power source of the
appliances. Moreover, the home control unit 7 outputs the
converted DC power to the DC power distribution board 8 via
a DC power line 14 or to a storage battery 16 via a DC power
line 15 so as to be stored therein.
The home control unit 7 not only acquires the AC power
through the AC power distribution board 11 but also supplies
the AC power to the AC power distribution board 11 by
converting the DC power from the fuel cell 3 or the storage
battery 16 into the AC power. The home control unit 7
exchanges data with the DC power distribution board 8
through a signal line 17.
The DC power distribution board 8 is a kind of a
breaker for DC power. The DC power distribution board 8
distributes the DC power inputted from the home control unit
7 and outputs the distributed DC power to- the control unit 9
via a DC power line 18 or to the relay unit 10 via a DC
power line 19. Further, the DC power distribution board 8
exchanges data with the control unit 9 via a signal line 20
or with the relay unit 10 via a signal line 21.
A plurality of DC appliances 5 is connected to the
control unit 9. The DC appliances 5 are connected to the
control unit 9 via DC supply lines 22 each of which has a
pair of lines capable of transmitting both of the DC power
and data therethrough. The electric power and the data are
transmitted to the DC appliances 5 through the respective DC
supply lines 22 by virtue of so-called power line
communications in which communications signals for
transmitting data with high-frequency carrier waves are
overlapped with the DC power to be supplied to the DC
appliances 5 by using a pair of lines. The control unit 9
acquires the DC power for the DC appliances 5 via the DC
power line 18 and determines which of the DC appliances 5 is
to be controlled in what manner based on an operation
instruction obtained from the DC power distribution board 8
via a signal line 20. Further, the control unit 9 outputs a
DC voltage and the operation instruction to the designated
DC appliances 5 via the corresponding DC supply line 22,
thereby controlling the operations of the DC appliances 5.
Switches 23 that are manipulated to switch operations
of the DC appliances 5 are connected to the control unit 9
via the DC supply line 22. Moreover, a sensor 24 for
detecting a radio wave transmitted from, e.g., an infrared
remote controller is connected to the control unit 9 via the
DC supply line 22. Thus, the DC appliances 5 are controlled
by transmitting communications signals through the DC supply
lines 22 in response to the manipulation of the switches 23
and the detection of the sensor 24 as well as the operation
instruction from the power distribution board 8.
The DC appliances 5 are connected to the relay unit 10
via respective DC power lines 25. The relay unit 10
acquires the DC power for the DC appliances 5 via the DC
power line 19 and determines which of the DC device 5 is to
be operated based on the operation instruction obtained from
the DC power distribution board 8 via the signal line 21.
Further, the relay unit 10 controls the operation of
the designated DC appliances 5 in such a way that the relays
installed therein turn on and off the supply of electric
powers to the DC power lines 25. Moreover, switches 26 for
use in manually switching the operations of the DC
appliances 5 are connected to the relay unit 10.
Accordingly, the DC appliances 5 are controlled by manually
manipulating the switches 2 6 to cause the relays to turn on
and off the supply of electric powers to the DC power lines
25.
A DC outlet 27 installed in each dwelling unit in the
form of, e.g., a wall outlet or a floor outlet is connected
to the DC power distribution board 8 via a DC power line 28.
When a plug (not shown) of one of the DC appliances 5 is
inserted in the DC outlet 27, it becomes possible to
directly supply the DC power to the corresponding DC
appliance.
Besides, a power meter 2 9 capable of remotely
measuring an amount of usage of an electric power from the
commercial power source 2 is connected between the
commercial AC power source 2 and the AC power distribution
board 11. In addition to the function of remotely measuring
the amount of usage of the electric power from the
commercial power source, the power meter 29 also has a
function of, e.g., power line communications or wireless
communications. The power meter 2 9 transmits the
measurement results to an electric power company or the like
through the power line communications, the wireless
communications or the like.
The power supply system 1 includes a network system 30
that makes it possible to control various kinds of home
appliances through network communications. The network
system 30 is provided with a home server 31 serving as a
control unit thereof. The home server 31 is connected to a
management server 32 outside home via a network N such as
Internet or the like, and also connected to a home appliance
34 via a signal line 33. Moreover, the home server 31 is
operated by using, as a power source, the DC power obtained
through the DC power distribution board 8 via a DC power
line 35.
A control box 36 for managing the operation control of
various kinds of home appliances through network
communications is connected to the home server 31 via a
signal line 37. The control box 36 is connected to the home
control unit 7 and the DC power distribution board 8 via a
single line 17, and can directly control the DC appliances 5
via a DC supply line 38. The control box 36 is connected
to, e.g., a gas/tap water meter 39 capable of remotely
reading, e.g., gas usage or water usage, and also connected
to a operation panel 40 of a network system 30. The
operation panel 40 is connected to a monitoring device 41
formed of, e.g., a door phone extension unit, a sensor or a
camera.
When operation instructions for various kinds of home
appliances are inputted through the network N, the home
server 31 informs the control box 36 of the instructions and
allows the control box 36 to control the home appliances to
be operated based on the instructions. Further, the home
server 31 can provide various kinds of information acquired
from the gas/tap water meter 39 to the management server 32
through the network N. Upon receiving abnormality detection
information from the monitoring device 41 through the
operation panel 40, the home server 31 provides an
information reception notice to the management server 32
through the network N.
As described above, in the residential complex 100,
the entire power distribution control is performed by the
general control unit 53.
Fig. 3 shows a configuration of the general control
unit 53. As shown in Fig. 3, the general control unit 53
includes a main line current monitoring unit 57 for
monitoring an electric current value at the inlet portion of
the main line 50 which is detected by the current sensors
52. The general control unit 53 further includes a current
level determination unit 58 for determining whether or not
the electric current value at the inlet portion of the main
unit 50 is excessive and a transmission unit 59 for
transmitting an instruction signal to the home control unit
7 of each dwelling unit 101 based on the determination
result.
Fig. 4 shows a configuration of the storage battery
control unit 56 for controlling the storage battery 55
connected to a side of the main line 50 which is opposite to
a side where the commercial AC power source is provided.
As shown in Fig. 4, the storage battery control unit
56 includes a receiving unit 60 for receiving an instruction
signal from the general control unit 53 and a controller 61
for controlling an operation of the AC/DC converter 54 based
on the received instruction signal.
Fig. 5 shows configurations of the home control unit 7
and the AC power distribution board 11 which are installed
in each dwelling unit 101.
As shown in Fig. 5, the AC power distribution board 11
has a main breaker 62 and a plurality of branch breakers 63.
The main breaker 62 serves as a breaker that cuts off an
electric connection between the main line 50 and the power
supply system 1 when the current supplied from the main line
50 becomes excessive. The branch breakers 63 serve as
breakers that cut off the supply of electric power to each
of AC loads provided in each dwelling unit when necessary.
The AC loads may be various kinds of AC electrical
appliances such as a lighting device, an air conditioner, a
home appliance, an audio/visual device and the like.
Meanwhile, the home control unit 7 has a receiving
unit 7 0 for receiving an instruction signal from the general
control unit 53, and a controller 71. The controller 71
controls operations of the loads 64 based on the instruction
signal received by the receiving unit 70. The controller 71
controls an operation of an AC/DC converter 72 and further
controls charging/discharging of the storage battery 16
based on the instruction signal received by the receiving
unit 70.
In the power distribution system for a building in
accordance with the present embodiment which is configured
as described above, when an overcurrent in the main line 50
is detected, the main line protection control for protecting
the main line 50 from the overcurrent is performed. The
main line protection control is carried out by initiating
the supply of electric powers from the storage battery 16
installed at each dwelling unit 101 and also from the
storage battery 55 connected to the side of the main line 50
which is opposite to the side where the commercial AC power
source is provided.
Fig. 6 shows a processing sequence of a main line
protection control routine employed in the present
embodiment. Further, the processing of this routine is
repeatedly performed by the general control unit 53 from
start to end.
When this routine is initiated, first, the general
control unit 53 receives an electric current value detected
by the current sensor 52 provided at the inlet portion of
the main line 50 in step S100. In step S101, the general
control unit 53 determines whether or not the current value
detected by the current sensor 52 is equal to or greater
than a first predetermined value. Moreover, in the present
embodiment, the first predetermined value is set to, e.g., a
current value corresponding to about 80% of a shutdown
current of the main line breaker 51.
If it is determined that the current value detected by
the current sensor 52 is less than the first predetermined
value (NO in step S101), the general control unit 53
proceeds to step S102 and outputs a power supply stop signal
to the home control unit 7 and the storage battery control
unit 56 in step S102. After outputting the power supply
stop signal, the general control unit 53 returns to step
S100. When the power supply stop signal is received while
the supply of electric power is being carried out, the home
control unit 7 and the storage battery control unit 56 stop
the supply of electric powers from the batteries 16 and 55.
On the other hand, when the current sensor 52 detects
a current value equal to or greater than the first
predetermined value (YES in step S101), the general control
unit 53 proceeds to step S103 and determines whether or not
the current value detected by the current sensor 52 is equal
to or greater than a second predetermined value in step
S103. In the present embodiment, the second predetermined
value is set to, e.g., a current value corresponding to
about 90% of a shutdown current of the main line breaker 51.
In other words, in the present embodiment, step S103
corresponds to a step of monitoring a value of an electric
current flowing from the commercial AC power source to the
main line 50. Furthermore, in the present invention, the
second predetermined value corresponds to the predetermined
current value for the initiation of main line protection.
If it is determined that the current value detected by
the current sensor 52 is less than the second predetermined
value (NO in step S103) , the general control unit 53 returns
to step S100.
If it is determined that the current value detected by
the current sensor 52 is equal to or greater than the second
predetermined value (YES in step S103), the general control
unit 53 transmits, in step S104, the power supply initiation
signals which initiate the supply of electric powers from
the batteries 16 and 55 to the home control unit 7 and the
storage battery control unit 56. Upon completion of the
transmission of the power supply initiation signals, the
general control unit 53 returns to step S100. When the
power supply initiation signals are received, the home
control unit 7 and the storage battery control unit 56
initiate the supply of electric powers from the batteries 16
and 55 in response to the received signals. Moreover, in
the present embodiment, step S104 corresponds to the
following steps.
• a step in which the supply of electric powers from
the batteries 16 and 55 installed at a building (a
residential complex 100) into the building is initiated when
the current value monitored in step S103 becomes equal to or
greater than the predetermined current value for the
initiation of main line protection.
• a step in which the supply of an electric power to
the main line 50 from the storage battery 55 connected to a
side of the main line 50 which is opposite to a side where
the commercial AC power source is provided is initiated when
the current value monitored in step S103 becomes equal to or
greater than the predetermined current value for the
initiation of main line protection.
• a step in which the supply of an electric power from
the storage battery 16 installed at the dwelling unit 101
(tenant) to the main line 50 is initiated when the current
value monitored in a step S103 becomes equal to or greater
than the predetermined current value for the initiation of
main line protection.
In the above-described embodiment, the residential
complex 100 corresponds to the building. Further, in the
above-described embodiment, the general control unit 53
performs the processes carried out by the protection unit.
The power distribution system for a building and a
protection method for the main line of the power
distribution system in accordance with the embodiment of the
present invention can provide following effects.
(1) In the power distribution system for a building
in accordance with the present embodiment, a commercial AC
power is distributed to each floor of the residential
complex 100 via the main line 50 which is wired to pass
through each floor of the residential complex 100. Further,
the power distribution system for a building of the present
embodiment includes the current sensor 52 for detecting a
value of an electric current flowing from the commercial AC
power source to the main line 50, and the batteries 16 and
55 installed at the residential complex 100. Moreover, the
general control unit 53 protects the main line 50 from an
overcurrent by initiating the supply of electric powers from
the batteries 16 and 55 to the residential complex 100 when
a current value detected by the current sensor 52 becomes
equal to or greater than a predetermined current value for
the initiation of main line protection.
More specifically, the general control unit 53
protects the main line 50 by initiating the supply of an
electric power to the main line 50 from the storage battery
55 connected to a side of the main line 50 which is opposite
to a side where the commercial AC power source is provided.
Further, the general control unit 53 protects the main line
50 by initiating the supply of an electric power from the
storage battery 16 provided at each dwelling unit 101 to the
main line 50. When the supply of the electric powers from
the batteries 16 and 55 is initiated, a part of the electric
power that has been entirely supplied from the commercial AC
power source is, in turn, supplied from the batteries 16 and
55 and, thus, the current flowing from the commercial AC
power source to the main line 50 is reduced.
At this time, since the reduced supply amount of
electric power from the commercial AC power source is
compensated by the supply amount of electric powers from the
batteries 16 and 55, the total supply amount of electric
powers after initiation of the protection control can be
maintained at the same level as that before the initiation
of the protection control.
Accordingly, in accordance with the above
configuration, the main line can be properly protected from
an overcurrent without stopping the supply of electric
power.
(2) In the protection method for a main line of the
power distribution system for a building in accordance with
the present embodiment, the main line 50 is protected from
an overcurrent by the following steps. At a first step, a
value of an electric current flowing from the commercial AC
power source to the main line 50 is monitored. At a second
step, the supply of electric powers from the batteries 16
and 55 installed at the residential complex 100 into the
residential complex 100 is initiated when the current value
monitored at the first step becomes equal to or greater than
a predetermined current value for the initiation of main
line protection.
More specifically, at the second step, the supply of
an electric power to the main line 50 from the storage
battery 55 installed at a side of the main line 50 which is
opposite to the side where the commercial AC power source is
provided is initiated. Further, at the second step, the
supply of an electric power from the storage battery 16
provided at each dwelling unit 101 is initiated. When the
supply of the electric powers from the batteries 16 and 55
is initiated, a part of the electric power that has been
supplied entirely from the commercial AC power source is
supplied, in turn, from the batteries 16 and 55 and, thus, a
current flowing from the commercial AC power source to the
main line 50 is reduced.
At this time, since the reduced supply amount of the
electric power from the commercial AC power source is
compensated by the supply amount of electric powers from the
batteries 16 and 55, the total supply amount of electric
powers after initiation of the protection control can be
maintained at the same level as that before the initiation
of the protection control.
Accordingly, in accordance with the above
configuration, the main line can be properly protected from
an overcurrent without stopping the supply of electric
power.
(Second embodiment)
Hereinafter, there will be described a power
distribution system for a building and a protection method
for a main line of the power distribution system in
accordance with a second embodiment of the present
invention. The present embodiment is the same as the first
embodiment except the conditions for stopping electric
powers which are supplied from the batteries 16 and 55 for
the protection of the main line 50.
In the first embodiment, when the current value at the
inlet portion of the main line 50, which is detected by the
current sensor 52, becomes lower : than the first
predetermined current value that is set to a current value
corresponding to about 80% of a shutdown current of the main
line breaker, the supply of electric powers from the
batteries 16 and 55 for the protection of the main line 50
is stopped. In that case, if the supply of the electric
powers from the batteries 16 and 55 is stopped, the current
value at the inlet portion of the main line 50 is increased
again. Thus, the supply of the electric powers from the
batteries 16 and 55 needs to be resumed.
Accordingly, in the present embodiment, the main line
protection control carried out by supplying electric powers
from the batteries is released after confirming that the
supply of the electric power from the commercial AC power
source does not become excessive even after stopping the
supply of the electric powers from the batteries 16 and 55.
Specifically, in the present embodiment, current
sensors (other current sensors) for detecting the values of
currents supplied from the batteries 16 and 55 are provided
at the batteries 16 and 55, respectively. Further, when the
sum of the current values from the batteries 16 and 55
detected by the current sensors and the current value at the
inlet portion of the main line 50 detected by the current
sensor 52 becomes equal to or lower than a predetermined
current value for the release of main line protection, the
supply of electric powers from the batteries 16 and 55 is
stopped. Herein, the current value for the release of main
line protection is set to be lower than the second
predetermined value. Therefore, even when the supply of
electric powers from the batteries 16 and 55 is stopped, the
current flowing through the inlet portion of the main line
50 is lower than the second predetermined value.
Further, in the present embodiment, the supply of
electric powers from the batteries 16 and 55 is stopped
based on the instruction from the general control unit 53.
Therefore, in the present embodiment, the general control
unit 53 corresponds to a release unit for stopping the
supply of electric power from the storage battery that is
controlled by the protection unit when the sum of the
current values detected by the current sensor and other
current sensors becomes equal to or lower than the
predetermined current value for the release of main line
protection.
In this regard, in the present embodiment, the current
value for release of main line protection is set to be
different by a predetermined constant value from the current
value for initiation of main line protection (the second
predetermined value). Thus, after the supply of electric
powers from the batteries 16 and 55 is initiated, the supply
of the electric powers from the batteries 16 and 55 is not
stopped unless the total value of the current supplied from
the commercial AC power source and the currents supplied
from the batteries 16 and 55 is sufficiently lower than the
predetermined current value for the initiation of main line
protection. Accordingly, the hunting of the protection
control, i.e., the resumption of the protection control of
the main line 50 immediately after the release of the
protection control of the main line 50, can be properly
prevented.
In addition, the above-described embodiments may be
modified as follows. .
In the second embodiment, there is set to be a
constant hysteresis between the main line protection
initiation current value (the second predetermined value)
and the main line protection release current value.
However, both current values may be the same when the
control hunting of the protection control can be neglected.
In the above-described embodiments, when the current
flowing through the inlet portion of the main line 50
becomes equal to or greater than the second predetermined
value, the supply of electric power is initiated from both
of the storage battery 16 installed at each dwelling unit
101 and the storage battery 55 connected to the side of the
main line 50 which is opposite to the side where the
commercial AC power source is provided.
However, if the main line 55 can be sufficiently
protected by either one of the batteries, the protection
control of the main line 50 can be performed by the supply
of an electric power from either one of the batteries 55 and
16. Further, when the main line 50 can be protected by the
storage battery 16 alone that is installed at each dwelling
unit 101, the storage battery 55 or the storage battery
control unit 56 can be omitted. In addition, when the main
line 50 is protected by the storage battery 55 alone, it is
unnecessary to provide the storage battery 16 at each
dwelling unit 101.
The above-illustrated embodiments have described the
cases in which the present invention is applied to the
residential complex 100. However, the power distribution
system or the protection method for a main line of the power
distribution system of the present invention can be applied
to another building other than the residential complex such
as a rental housing and the like. For example, the present
invention can be applied to a power distribution system for
distributing electric power to each floor of a building via
a main line which is wired to pass through each section in
the floor of the building.
While the invention has been described with respect to
the embodiments, the present invention is not limited to the
above embodiments and can be variously modified and changed
without departing from the scope of the invention as defined
in the following claims, and such changes and modifications
are also included in the scope of the present invention.
We claim:
1. A power distribution system for a building, comprising:
an electric current sensor for detecting a current
value of an electric current flowing from a commercial AC
power source through a main line in a building; and
a storage battery installed at the building,
wherein when the current value detected by the
electric current sensor reaches a predetermined value, a
supply of an electric power to the building from the storage
battery is initiated.
2. The power distribution system of claim 1, further
comprising an overcurrent protection unit, wherein the
building includes a plurality of sections individually
equipped with electric power supply systems, and the
overcurrent protection unit protects the main line of the
building from an overcurrent by initiating the supply of the
electric power from the storage battery to the building when
the current value detected by the electric current sensor
becomes equal to or greater than a predetermined current
value for the initiation of main line protection.
3. The power distribution system of claim 2, wherein the
storage battery is provided at a side of the main line which
is opposite to a side where the commercial AC power source
is provided, and the overcurrent protection unit initiates
the supply of the electric power from the storage battery to
the building.
4. The power distribution system of claim 2, wherein the
storage battery is provided at each of the sections, and the
overcurrent protection unit initiates the supply of the
electric power from the storage battery to the main line in
the building.
5. The power distribution system of any one of claims 2 to
4, further comprising: a storage battery current sensor for
detecting a current value of an electric current supplied
from the storage battery; and a release unit for stopping
the supply of the electric power from the storage battery
which is carried out by the overcurrent protection unit when
the sum of the current values detected by the electric
current sensor and the storage battery current sensor
becomes equal to or lower than a predetermined current value
for the release of main line protection.
6. The power distribution system of claim 5, wherein the
current value for the release of the main line protection is
set to be different by a predetermined constant value from
the current value for the initiation of the main line
protection.
7. A method for protecting a main line of a building from
an overcurrent in a power distribution system for
distributing an electric power to each floor of the building
via the main line which is wired to pass through each floor
of the building, the method comprising:
detecting a current value of an electric current
flowing from a commercial power source through the main
line; and
initiating a supply of an electric power to the
building from a storage battery installed at the building
when the detected current value becomes equal to or greater
than a predetermined current value for the initiation of
main line protection.

ABSTRACT

A power distribution system for a building includes an electric current sensor for detecting a value of a
current flowing from a commercial AC power source through a main line in a building and a storage
battery installed in the building. When the current value detected by the electric current sensor reaches a
predetermined value, a supply of an electric power to the building from the storage battery is initiated.
The power distribution system further includes an overcurrent protection unit. The building includes
sections individually equipped with electric power supply systems, and the overcurrent protection unit
protects the main line of the building from an overcurrent by initiating the supply of the electric power
from the storage battery to the building when the current value detected by the electric current sensor
becomes equal to or greater than a predetermined current value for the initiation of main line protection.