The present invention relates to a technique for monitoring a power
system.
[Background Art]
[0002]
Large-scale introduction, into power systems, of power sources
having output thereof fluctuating in accordance with weather
(output-fluctuating power sources), such as those based on
renewable energy (solar power generation, wind turbine generation,
and the like), is now on the drawing board. The proportion of power
sources based on renewable energy might increases, and the
proportion of power sources for which supply and demand are
adjustable, such as thermal power generation, might decrease.
Meanwhile, since the output of renewable energy fluctuates in
accordance with weather, demand fluctuation may occur, there may
be cases where the supply-demand adjustment power of the power
system is deficient with power supply dependent on a supply-demand
adjustment power of thermal power generation, etc.
[0003]
In a known technique for achieving higher supply-demand adjustment
power, the supply-demand adjustment power of the power system is
prevented from becoming insufficient, by using an inverter
2
interconnected power source having a function of supplying power
to the power system via an inverter in interconnected fashion, in
addition to a rotating power source (thermal power generation, etc.)
having a function of supplying power that is generated by a rotator.
[0004]
PTL 1 has the following description: "a monitoring and controlling
device for a power system, in which information is communicated
between an inverter interconnected power source, having a function
of supplying power to the power system via an inverter in
interconnected fashion, and a rotating power source, having a
function of supplying power generated by a rotator to the power
system, includes: a unit configured to recognize a power adjustable
amount in accordance with an operation state of a plurality of the
inverter interconnected power sources coupled to the power system
and an operation state of the rotating power source; a unit
configured to determine an output adjustment control parameter for
the inverter interconnected power source, based on the power
adjustable amount; and a unit for distributing a control signal
to the inverter interconnected power sources in accordance with
a value of the parameter".
[0005]
PTL 2 has the following description: "a power estimation device
configured to estimate a value of second power in such a manner
that, on a power line coupled to an electric power load and a
distributed power source for supplying power to the electric power
load, the second power is generated after first power is generated
3
on an upstream side of the distributed power source, includes: a
first estimation unit configured to estimate, after third power
is supplied to the electric power load, a value of fourth power
to be supplied to the electric power load, based on a value of the
third power; a second estimation unit configured to estimate, after
fifth power from the distributed power source to the power load
is generated, sixth power to be generated from the distributed power
source to the power load, in accordance with a product of a constant
and an estimated value of an amount of solar radiation at a position
where the distributed power source is provided; and a third
estimation unit configured to estimate a value of the second power
in accordance with a difference between the value of the fourth
power and the value of the sixth power".
[0006]
PTL 3 has the following description: "a power generation system
includes: a power generation facility that uses a renewable energy;
a first storage battery that is to be charged with electrical power
supplied from the power generation facility; a second storage
battery that supplies electrical power to a power system; a
connection switching device that switches between the first storage
battery and the second storage battery; and a controller that
controls the connection switching device, wherein the controller
implements control so as to enable switching of the connection
switching device at a switching timing that is determined in
accordance with a predicted amount of an electrical power generation
by the power generation facility and with a predicted demand of
4
the power system".
[Citation List]
[Patent Literature]
[0007]
[PTL 1]
Japanese Patent Application Publication No. 2014-128137
[PTL 2]
Japanese Patent Application Publication No. 2014-135872
[PTL 3]
Japanese Patent Application Publication No. 2014-113034
[Summary of Invention]
[Technical Problem]
[0008]
A correlation between a fluctuation cycle and a demand fluctuation
range changes when, with the passage of time, output of a renewable
energy sharply fluctuates in accordance with weather or a power
or system configuration changes. It is difficult to determine
whether adjustment power is deficient for a predetermined
fluctuation cycle, when the correlation changes.
[Solution to Problem]
[0009]
A power system monitoring device as one aspect of the present
invention for solving the problem includes: a communication unit
configured to receive measurement data measured in a power system;
a storage unit configured to store the measurement data, store
configuration data representing a configuration of the power system,
5
and store adjustment power representing an ability to adjust output
according to a component of a specific cycle among power
fluctuations within a preset designated area within the power
system; and a calculation unit configured to calculate demand data
as time sequence data on a demand within the designated area based
on the measurement data and the configuration data, calculate a
plurality of fluctuation amounts each indicating a size of a
component of a corresponding one of a plurality of cycles in the
demand data, calculate a correlation between the plurality of cycles
and the plurality of fluctuation amounts, calculate a fluctuation
amount of the specific cycle based on the correlation, and compare
the fluctuation amount of the specific cycle with a size of the
adjustment power of the specific cycle.
[Advantageous Effects of Invention]
[0010]
Whether adjustment power is deficient in a specific fluctuation
cycle can be determined, even when a correlation between a
fluctuation cycle and a demand fluctuation range changes.
[Brief Description of Drawings]
[0011]
[Fig. 1]
Fig. 1 is a diagram illustrating a functional configuration of a
monitoring control device 10 according to Embodiment 1.
[Fig. 2]
Fig. 2 is a diagram illustrating a configuration of the monitoring
control device 10 and a power system 100.
6
[Fig. 3]
Fig. 3 illustrates a content of a program database 20.
[Fig. 4]
Fig. 4 is a diagram illustrating demand calculation data in setting
data D3.
[Fig. 5]
Fig. 5 is a diagram illustrating designated fluctuation cycle data
in the setting data D3.
[Fig. 6]
Fig. 6 is a diagram illustrating adjustment power data D4.
[Fig. 7]
Fig. 7 is a diagram illustrating demand data D7.
[Fig. 8]
Fig. 8 is a diagram illustrating demand fluctuation range estimation
result data D8.
[Fig. 9]
Fig. 9 is a diagram illustrating adjustment power determination
result data D10
[Fig. 10]
Fig. 10 is a diagram illustrating calculation processing executed
by the monitoring control device 10.
[Fig. 11]
Fig. 11 is a diagram illustrating a functional configuration of
a monitoring control device 10b according to Embodiment 2.
[Fig. 12]
Fig. 12 is a diagram illustrating a configuration of an output
7
adjustment amount determination unit 0103.
[Description of Embodiments]
[0012]
Embodiments of the present invention are described below with
referent to drawings.
[Embodiment 1]
[0013]
A monitoring control device 10 for a power system according to the
present embodiment calculates a demand within a designated area
by using system measurement data D1, system facility data D2, and
setting data D3; estimates a demand fluctuation range in a
designated fluctuation cycle by using demand data D7 obtained by
the calculation and the setting data D3; estimates a correlation
between a fluctuation cycle and a demand fluctuation range by using
demand fluctuation range estimation result data D8 obtained by the
calculation and the setting data D3; determines adjustment power
by using correlation estimation result data D9 obtained by the
calculation, the system facility data D2, and the adjustment power
data D4; and displays one or a plurality of the designated area
demand calculation result, the demand fluctuation range estimation
result, the correlation estimation result, and the adjustment power
determination result on a screen.
[0014]
Fig. 1 illustrates a functional configuration of the monitoring
control device 10 according to Embodiment 1.
[0015]
8
The monitoring control device 10 includes system measurement data
D1, a monitoring control calculation unit 40, a monitoring control
calculation results database 41, a system database 42, a screen
display unit 35, and a data management unit 36. The monitoring
control calculation unit 40 includes a demand calculation unit 31,
a demand fluctuation range estimation unit 32, a correlation
estimation unit 33, and an adjustment power determination unit 34.
The system database 42 stores system data D42. The system data D42
includes system facility data D2, setting data D3, and adjustment
power data D4. The monitoring control calculation results database
41 stores monitoring control calculation results data D41. The
monitoring control calculation results data D41 includes demand
data D7, demand fluctuation range estimation results data D8, and
correlation estimation results data D9.
[0016]
The demand calculation unit 31 uses the system measurement data
D1, the system facility data D2, and the setting data D3 to calculate
the demand data D7 indicating a demand in a designated area. The
demand fluctuation range estimation unit 32 uses the demand data
D7 and the setting data D3 to perform calculation for estimating
a demand fluctuation range, and outputs the demand fluctuation range
estimation results data D8 as the result of the calculation. The
correlation estimation unit 33 uses the demand fluctuation range
estimation results data D8 and the setting data D3 to perform
calculation for estimating correlation between a fluctuation cycle
and a demand fluctuation range, and outputs the correlation
9
estimation results data D9 as the result of the calculation. The
adjustment power determination unit 34 uses the correlation
estimation results data D9, the system facility data D2, and the
adjustment power data D4 to determine an adjustment power planned
value, and outputs adjustment power determination results data D10
as the result of the determination. The screen display unit 35
displays one or a plurality of the demand data D7, the demand
fluctuation range estimation results data D8, and the correlation
estimation results data D9 on a screen.
[0017]
Fig. 2 illustrates configurations of the monitoring control device
10 and a power system 100.
[0018]
When elements need not to be distinguished from each other with
an alphabet in their reference numerals, the alphabet may be omitted
from the reference numeral. The monitoring control device 10 is
coupled to the power system 100 through a communication network
300. The power system 100 includes a node (bus) 120 and a
measurement device 44 that is coupled to the node 120 and performs
measurement related to power. The nodes 120 is coupled to the power
source 110 and a load 150 via a branch (line) 140, a transformer
130, and a node 121. The power system 100 may be further coupled
to: an electric appliance that can be controlled by the monitoring
control device 10 (a battery, a secondary battery that can be charged
and discharged, a storage battery for an EV, a flywheel, phase
modifying equipment (power capacitor: SC: Static Condenser, ShR:
10
Shunt Reactor), SVC (Static Var Compensator), SVG (Static Var
Generator), LPC (Loop Power Controller) and the like.
[0019]
For example, the power source 110 may include: a rotating power
source such as a thermal power generator, a hydroelectric generator,
and a nuclear power generator; an inverter interconnected power
source such as a solar power generator and a wind turbine generator;
and a distributed power source such other renewable energy generator
and an electrical storage device.
[0020]
For example, the measurement device 44 is a device (such as VT:
Voltage Transformer, PT: Potential Transformer, or CT: Current
Transformer) that measures one or a plurality of node voltage V,
branch current I, power factor Φ, active power P, and reactive power
Q, and may also be a Telemeter (TM) that transmits data, including
a data measurement location identification ID, a timestamp, and
the measurement value to the communication network 300. The
measurement device 44 may be a device that measures power
information (voltage phasor information) with absolute time using
a GPS (Global Positioning System), a phase measurement device (PMU:
Phasor Measurement Units), or other electric appliances. The
measurement device 44, which is in the power system 100 in the
figure, may be provided to the power source 110, the transformer
130, the load 150, the node 121, the branch 140, or the like.
[0021]
The monitoring control device 10 includes a display unit 11, an
11
input unit 12 such as a keyboard and a mouse, a communication unit
13, a computer and a computer server (CPU: Central Processing Unit)
14, a memory 15, various databases (a program database 20, a system
measurement database 21, a system facility database 22, a setting
database 23, an adjustment power database 24, a demand database
27, a demand fluctuation range estimation results database 28, a
correlation estimation results database 29, and an adjustment power
determination results database 30) that are coupled to a bus line
43. The databases may be stored in one or a plurality of storage
devices or may be stored in the memory 15.
[0022]
For example, the display unit 11 is a display apparatus. For
example, the display unit 11 may include a printer apparatus and
a voice output apparatus, in addition to or instead of the display
apparatus. The input unit 12 may include at least one of a keyboard
switch, a pointing device such as a mouse, a touch panel, and a
voice instruction apparatus. The display unit 11 and the input unit
12 may be in another computer coupled to the monitoring control
device 10 via the communication network 300. For example, the
communication unit 13 is a circuit that uses a communication
protocol for coupling to the communication network 300. The CPU
14 reads a predetermined computer program from the program database
20, and executes the program. The CPU 14 may be one or a plurality
of semiconductor chips, or may be a computer device such as a
computer server. For example, the memory 15 is a RAM (Random Access
Memory), and stores the computer program read from the program
12
database 20, calculation result data required for various types
of processing, image data, and the like. Screen data stored in the
memory 15 is transmitted to the display unit 11 to be displayed.
An example of the screen to be displayed is described later.
[0023]
Fig. 3 illustrates a detail of the program database 20.
[0024]
For example, the program database 20 stores program data D11
including: a demand calculation program P10, a demand fluctuation
range estimation program P20, a correlation estimation program P30,
an adjustment power determination program P40, a screen display
program P50, and a data management program P60.
[0025]
The CPU 14 executes the demand calculation program P10, the demand
fluctuation range estimation program P20, the correlation
estimation program P30, the adjustment power determination program
P40, the screen display program P50, the data management program
P60, a system frequency detection program P70, and an output
adjustment amount determination program P80 read onto the memory
15 from the program database 20, whereby the demand calculation
unit 31, the demand fluctuation range estimation unit 32, the
correlation estimation unit 33, the adjustment power determination
unit 34, the screen display unit 35, the data management unit 36
are respectively implemented. Any of these functions may be
implemented by a hardware circuit. The memory 15 temporarily
stores image data to be displayed, the system measurement data D1,
13
temporary data for each calculation, and result data of each
calculation. The CPU 14 generates necessary image data and causes
the display unit 11 (for example, a display screen) to display the
image. The display unit 11 may only display a simple screen only
used for rewriting each control program and database.
[0026]
A plurality of databases stored in the monitoring control device
10, except for the program database 20, are described below.
[0027]
The system measurement database 21 stores the system measurement
data D1. The system measurement data D1 includes the active power
P, reactive power Q, voltage V, voltage phase angle δ, current I,
power factor Φ, or the like periodically measured. For example,
the system measurement data D1 is each data measured by the
measurement device 44. The monitoring control device 10 receives
the system measurement data D1 from the measurement device 44 via
the communication network 300, and stores the data in the system
measurement database 21. Instead of being directly received from
the measurement device 44 by the monitoring control device 10, the
system measurement data D1 may be aggregated in another monitoring
device and then may be received by the monitoring control device
10 via the communication network 300. For example, the monitoring
device may be a central load-dispatching office, a system stability
monitoring server, an EMS (Energy Management System), the
monitoring control device 10 of other types, or the like. The system
measurement data D1 may include a unique number for identifying
14
data and a timestamp, and may be PMU data. For example, the system
measurement data D1 stores one or a plurality of: voltage and a
voltage phase angle of a node 120a and a node 120c coupled to the
power system 100; line current (I) or line power flow (P + jQ) of
branches 140a and 140c coupled to the nodes 120a and 120c in the
power system 100; line current (I) or line power flow (P + jQ) of
the transformers 130a and 130c coupled to the nodes 120a and 120c
in the power system 100; voltage V and a voltage phase angle δ of
nodes 121a and 121c coupled to the transformers 130a and 130c;
voltage V, current I, active power P, reactive power Q, and power
factor Φ of a load 150a and a load 150c coupled to the nodes 121a
and 121c; and a measurement value receives from the measurement
device 44, the monitoring device, and the like via the communication
network 300. The measurement value to be received corresponds to
voltage V, current I, active power P, reactive power Q, power factor
Φ, voltage V, voltage phase angle δ, and the like of other nodes,
branches, power sources, loads, control devices, or the like coupled
to the power system 100. The voltage phase angle δ may be measured
by using other measurement devices using PMU and GPS. The
monitoring control device 10 can calculate the line power flow (P
+ jQ) from the current I, voltage V, and power factor Φ measured
by the measurement device 44.
[0028]
The system facility database 22 stores the system facility data
D2. The system facility data D2 includes a system configuration
(topology), line impedance (R + jX), earth capacity (admittance:
15
Y ) , generator data, and the like. The system configuration
includes coupling relationship of one or a plurality of the node
120, the branch 140, the power source 110, the load 150, the
transformer 130, and each measurement device 44 in the system. The
system facility data D2 may be acquired from the monitoring control
device 10, the central load-dispatching office, or the EMS, or may
be manually input. When the manual input is employed, the data is
manually input through the input unit 12 and is stored. For
performing the input, the CPU 14 generates required image data,
and causes the display unit 11 to display the image. A completion
function may be utilized to achieve semi-manual input for setting
a large amount of data.
[0029]
The setting database 23 stores the setting data D3.
[0030]
Fig. 4 illustrates demand calculation data in the setting data D3.
[0031]
The setting data D3 includes a designated area and demand
calculation data for calculating the demand in the area, for each
time point. In the illustrated example, for example, the demand
calculation data indicates that a demand in an area a and an area
b, as designated areas in the power system 100, are calculated by
adding a measurement value indicating a demand measured by the
measurement device 44a with a measurement value indicating a demand
measured by the measurement device 44b, based on the system
configuration in the system facility data D2.
16
[0032]
Fig. 5 illustrates designated fluctuation cycle data in the setting
data D3.
[0033]
The setting data D3 includes the designated fluctuation cycle data.
The designated fluctuation cycle data includes a designated
fluctuation cycle for each time point. The designated fluctuation
cycle is a fluctuation cycle that is set as an object of the demand
fluctuation range calculation in advance. A plurality of
designated fluctuation cycles may be set for each time point. The
designated fluctuation cycle may be a designated fluctuation cycle
bandwidth as a fluctuation cycle bandwidth designated in advance.
The fluctuation cycle bandwidth indicates a range of the fluctuation
cycles. The fluctuation cycle bandwidth may be defined by the
center fluctuation cycle, or may be defined by upper and lower limit
fluctuation cycles. For example, the designated fluctuation cycle
bandwidth may be a fluctuation cycle bandwidth that is likely to
involve a deficient adjustment power planned value due to output
adjustment by the central load-dispatching office or the like.
Thus, the central load-dispatching office and the monitoring and
controlling device 10 can be in charge of the output adjusted
bandwidth. In the power system 100 without the central
load-dispatching office for remote islands and the like, the
monitoring control device 10 can perform the output adjustment
instead of the central load-dispatching office. The monitoring
control device 10 may detect a fluctuation cycle bandwidth involving
17
a deficient adjustment power planned value through the calculation
processing, and may set the detected fluctuation cycle bandwidth
as the designated fluctuation cycle bandwidth in the calculation
processing executed thereafter. A variable frequency, which is a
reciprocal of the fluctuation cycle, may be used instead of the
fluctuation cycle.
[0034]
The adjustment power database 24 stores the adjustment power data
D4.
[0035]
Fig. 6 illustrates the adjustment power data D4.
[0036]
The adjustment power data D4 includes: a target ID indicating a
target electric appliance, including a rotating power source, an
inverter interconnected power source, and other controllable
electric appliances (a battery, a secondary battery that can be
charged and discharged, a storage battery for an EV, a flywheel,
or the like) that can perform supply-demand adjustment, as well
as a bus or the like coupled to the target electric appliance; an
adjustable fluctuation cycle indicating a fluctuation cycle
adjustable by the target electric appliance; and an adjustment power
planned value for each time period. As illustrated in the figure,
the adjustable fluctuation cycle may be an adjustable fluctuation
cycle bandwidth as a range of the adjustable fluctuation cycles.
The adjustable fluctuation cycle bandwidth may be defined by the
upper and lower fluctuation cycles or by the center fluctuation
18
cycle. The adjustment power planned value indicates an ability to
maintain the system frequency of the power system 100 against the
fluctuation of the supply-demand balance. The adjustment power
planned value indicates an output adjustment amount range as a range
of output adjustment amounts adjustable in the adjustable
fluctuation cycle. The adjustment power planned value may be
represented by any one of a planned output, a capacity, a current
output, and an output upper/lower limit of the target electric
appliance.
[0037]
The adjustment power planned value may include: a negative value
indicating a lower limit of the output adjustment amount range;
and a positive value indicating an upper limit of the output
adjustment amount range. The negative and positive values may have
the same absolute value as illustrated in the figure, or may have
different absolute values. When the lower limit of the output
adjustment amount rang is 0, the adjustment power planned value
may only include the positive value indicating the upper limit of
the output adjustment amount range. When the upper limit of the
output adjustment amount range is 0, the adjustment power planned
value may only include the negative value indicating the lower limit
of the output adjustment amount range. The adjustment power
planned value differs among the types of the power source 110. For
example, the adjustment power planned value only indicates the
positive value, when the rotating power source, such as a gas
turbine, is in standby or is operating under a minimum output (around
19
0) that cannot be reduced any further. The adjustment power planned
value only indicates the negative value when the rotating power
source is operating with output close to rated output that cannot
be increased any further. In a case where the speed of increasing
the output by increasing the fuel of the power source 110 is slow
and the speed of reducing the output by throttling the valve is
fast or in the other like cases, the adjustment power planned value
may have a negative value with a larger absolute value than a
positive value. Limitation on the output, for ensuring the
adjustment power planned value of a solar power generation or the
like, leads to reduction of a selling electricity amount from a
customer, and thus the output limitation may be avoided.
[0038]
The adjustment power data D4 may be input from a worker (operator)
by using the input unit 12, may be periodically received from the
target electric appliance or the monitoring device, or may be
calculated by the monitoring control device 10 based on the system
measurement data D1 and the system facility data D2. The central
load-dispatching office may transmit a schedule of the adjustment
power planned value to the monitoring control device 10 and the
electric appliance. The designated fluctuation cycle may be the
same as the adjustable fluctuation cycle.
[0039]
The demand database 27 stores the demand data D7.
[0040]
Fig. 7 illustrates the demand data D7.
20
[0041]
In the figure, the horizontal axis represents a time point t and
a vertical axis represents a demand L. The demand data D7 indicates
a result of calculating time sequence data on the demand in the
designated area at past time points. The demand data D7 is
calculated by the demand calculation unit 31. The demand data D7
may be set in advance, or may be a value set by the monitoring device
and received by the communication unit 13 via the communication
network 300. With these setting methods, the demand data D7 can
be flexibly set. The demand data fluctuates in accordance with the
change in the used condition of the load 150 by the customer, and
a change in an amount of solar radiation or the like when the power
source 110 is the solar power generation.
[0042]
The demand fluctuation range estimation unit 32 uses the demand
data D7 and the setting data D3 to calculate the demand fluctuation
range indicating the size of a component of the designated
fluctuation cycle in the demand data D7. As illustrated in the
figure, the demand fluctuation range estimation unit 32 determines
a time point ti that is earlier than the current time point t0 by
a monitoring time Ts, and sets a period between ti and t0 as a
monitoring period. The demand fluctuation range estimation unit
32 sets a time window corresponding to a length of a designated
fluctuation cycle Ti within the monitoring period, and calculates
a short term fluctuation range representing a difference between
the maximum value and the minimum value of the time sequence data
21
of the demand in the time window. Furthermore, the demand
fluctuation range estimation unit 32 scans the monitoring period
with the time window, and calculates the maximum value a plurality
of short term fluctuation ranges obtained by the scanning. The
designated fluctuation cycle and the demand fluctuation range are
included in the demand fluctuation range estimation results data
D8. Thus, the demand fluctuation range estimation unit 32 can
calculate the size of the component of the designated fluctuation
cycle in the fluctuation of the demand. The demand fluctuation
range estimation unit 32 may calculate the demand fluctuation range,
in each of the plurality of designated fluctuation cycles, to be
included in the demand fluctuation range estimation results data
D8. The demand fluctuation range estimation unit 32 may obtain the
demand fluctuation range as the demand fluctuation range of the
designated fluctuation cycle bandwidth with the designated
fluctuation cycle at the center. In such a case, the width of the
designated fluctuation cycle bandwidth may be determined based on
the band width of the time window.
[0043]
The demand fluctuation range estimation unit 32 may calculate the
demand fluctuation range as a value (for example, 3σ) based on a
standard deviation of the plurality of short term fluctuation ranges
obtained within the monitoring period or the like, instead of the
maximum value of the plurality of short term fluctuation ranges
obtained within the monitoring period. The demand fluctuation
range estimation unit 32 may calculate the maximum value of the
22
absolute value of the difference between two adjacent samples in
the time window as the short term fluctuation range. The demand
fluctuation range estimation unit 32 may further perform frequency
analysis such as Fourier transform to calculate the demand
fluctuation range as a size of a component of each of the plurality
of designated fluctuation cycles set in advance.
[0044]
The demand fluctuation range estimation results database 28 stores
the demand fluctuation range estimation results data D8.
[0045]
Fig. 8 illustrates the demand fluctuation range estimation results
data D8.
[0046]
In the figure, the horizontal axis represents a fluctuation cycle
T and the vertical axis represents the demand fluctuation range
ΔL. Circle marks in the figure represent points as the designated
fluctuation cycle and the demand fluctuation range in the demand
fluctuation range estimation results data D8. The designated
fluctuation cycle may be represented by fluctuation cycle bandwidth
such as T1 to T2, T2 to T3, and T3 to T4 or may be represented by
a fluctuation cycle such as a designated fluctuation cycle Ti. The
correlation estimation unit 33 may use the setting data D3 and the
demand fluctuation range estimation results data D8 to estimate
the correlation between the fluctuation cycle and the demand
fluctuation range as the correlation estimation results data D9.
For example, the correlation estimation unit 33 may perform
23
approximation with a plurality of sets of designated fluctuation
cycle and demand fluctuation range through a least-squares method,
to estimate the correlation between the fluctuation cycle and the
demand fluctuation range. Thus, the monitoring control device 10
can obtain a continuous correlation from sets of discrete
fluctuation cycle and demand fluctuation range. A demand
fluctuation range of any fluctuation cycle can be obtained by using
the correlation. Two curves in the figure are a curve obtained by
the previous calculation processing and a curve obtained by the
latest calculation processing, and represent the correlation
between the fluctuation cycle and the demand fluctuation range in
the correlation estimation results data D9. The correlation
estimation results database 29 stores the correlation estimation
results data D9.
[0047]
Fig. 9 illustrates the adjustment power determination results data
D10.
[0048]
In the figure, the horizontal axis represents the fluctuation cycle
T and the vertical axis represents the demand fluctuation range
ΔL. Two curves in the figure is a curve representing the correlation
obtained by the previous calculation processing executed earlier
than the current time point by the time Ts, and a curve representing
the correlation obtained by the latest calculation processing, in
the correlation estimation results data D9. The adjustment power
determination unit 34 uses the system facility data D2, the
24
adjustment power data D4, and the correlation estimation result
data D9 to compare the demand fluctuation range with the adjustment
power evaluation value, representing the amount of the adjustment
power planned value, for each fluctuation cycle to detect a
deficient fluctuation cycle with the adjustment power evaluation
value being overwhelmed by the demand fluctuation range, calculates
the shortage amount of the adjustment power evaluation value with
respect to the demand fluctuation range in the deficient fluctuation
cycle, and stores the deficient fluctuation cycle and the shortage
amount as the adjustment power determination results data D10. In
the figure, the height of each bar graph that corresponds to each
designated fluctuation cycle bandwidth and is overlapped with the
correlation curves represents the adjustment power evaluation
value. The height of a hatched portion of the bar graph represents
the shortage amount. The adjustment power determination results
database 30 stores the adjustment power determination results data
D10. For example, the adjustment power evaluation value is an
absolute value of the positive value or the negative value indicated
by the adjustment power planned value. When the adjustment power
planned value indicates both positive value and negative value,
the adjustment power evaluation value is a smaller one of an absolute
value of the positive value or an absolute value of the negative
value, for example. When the adjustment power planned value
indicates the positive value and the negative value, the adjustment
power determination unit 34 may use a value obtained by subtracting
the negative value from the positive value, as an adjustment power
25
evaluation value less strict than the adjustment power evaluation
value described above. When the adjustment power determination
unit 34 calculates the shortage amount, the operator or the
adjustment power determination unit 34 can change the adjustment
power planned value to prevent the shortage of the adjustment power.
[0049]
The calculation processing executed by the monitoring control
device 10 is described below.
[0050]
Fig. 10 illustrates the calculation processing executed by the
monitoring control device 10.
[0051]
First of all, a flow of the processing is briefly described. The
monitoring control device 10 stores the system facility data D2,
the setting data D3, and the adjustment power data D4 that are input
(step S1), and receives and stores the system measurement data D1
(step S2). Then, the monitoring control device 10 uses the system
measurement data D1, the system facility data D2, and the setting
data D3 to perform demand calculation, and stores the demand
database D7 as the calculation result in the demand database 27
(step S3). Next, the monitoring control device 10 uses the
calculated demand data D7 and the setting data D3 to estimate the
demand fluctuation range, and stores the demand fluctuation range
estimation results data D8 as the calculation result in the demand
fluctuation range estimation results database 28 (step S 4 ) . Then,
the monitoring control device 10 uses the demand fluctuation range
26
estimation results data D8 and the setting data D3 to estimate the
correlation between the fluctuation cycle and the demand
fluctuation range, and stores the correlation estimation results
data D9 as the calculation result in the correlation estimation
results database 29 (step S 5 ) . Then, the monitoring control device
10 uses the correlation estimation results data D9, the system
facility data D2, and the adjustment power data D4 to determine
the adjustment power planned value, and stores the adjustment power
determination results data D10 as the determination result in the
adjustment power determination results database 30 (step S6). As
a final step, the monitoring control device 10 cause the display
unit 11 to display a screen including one or a plurality of the
demand data D7, the demand fluctuation range estimation results
data D8, the correlation estimation results data D9, and the
adjustment power determination results data D10 (step S 6 ) , and the
flow is terminated. The monitoring control device 10 executes
steps S4, S5, S6, and S7 every time an update time elapses. For
example, the update time may be the monitoring time, or may be a
time shorter than the monitoring time. The monitoring control
device 10 may use a monitoring time set in advance, or may change
the monitoring time in accordance with the result of the calculation
result as described later.
[0052]
The monitoring control device 10 may appropriately display various
calculation results and data, stored in the memory 15 while the
calculation is in process, on the screen of the monitoring device.
27
Thus, the operator can easily recognize the operation state of the
monitoring control device 10 of the power system.
[0053]
Each step in the flow of processing described above is described.
[0054]
First of all, in step S1, when the system facility data D2, the
setting data D3, and the adjustment power data D4 are not set in
advance, the data management unit 36 receives the system facility
data D2, the setting data D3, and the adjustment power data D4 input
from the operator by using the input unit 12 and the display unit
11. The data management unit 36 may receive the system facility
data D2, the setting data D3, and the adjustment power data D4 from
the monitoring device via the communication network 300 and the
communication unit 13, or may automatically receive at a fixed cycle
data related to the system facility data D2, the setting data D3,
and the adjustment power data D4 held by the monitoring device or
the like, and store the data in the corresponding database. For
example, the data management unit 36 receives data corresponding
to a single day, with values at 30 minutes interval, once a day.
When the system facility data D2, the setting data D3, and the
adjustment power data D4 are set in advance, the data management
unit 36 corrects the data in accordance with an input from the
operator, or may directly use the data.
[0055]
In step S2, the data management unit 36 receives the system
measurement data D1 via the communication network 300 and stores
28
the data in the system measurement database 21.
[0056]
In step S3, the demand calculation unit 31 uses the system facility
data D2 stored in step S1, the demand calculation data in the setting
data D3, and the system measurement data D1 stored in step S2 to
calculate the time sequence data on the demand, and stores the result
as the demand data D7. The demand calculation unit 31 calculates
the sum of the load values in the designated area in the system
measurement data D1, from the coupling relationship of one or a
plurality of the node 120, the branch 140, the power source 110,
the load 150, the transformer 130, and the electric appliance and
from the relationship with the designated area, based on the system
facility data D2, to calculate the sum of the demands in the
designated area as the demand data D7. As described above, the
demand calculation unit 31 can calculate the demand data D7 by
identifying the load value in the designated area in the system
measurement data D1 based on the demand calculation data, and
calculating the sum of the identified load values. The demand
calculation unit 31 may calculate the demand fluctuation in the
designated area based on the output of the power source 110, the
use condition of the load 150, a power flow to and from another
area, and a power transmission loss in the designated area. The
demand calculation unit 31 may select a portion, in the designated
area, where the past system measurement data D1 is obtained and
the system measurement data D1 at the latest time point is not
obtained, as a defective portion, select a portion similar to the
29
defective portion in the past system measurement data D1 as a similar
portion, and can use the system measurement data D1 in the similar
portion at the latest time point instead of the system measurement
data D1 of the defective portion at the latest time point. In the
case of the solar power generation, the similar portion may be the
solar power generation with the same amount of solar radiation.
When the designated area defined by a virtual boundary known as
a fence, the demand calculation unit 31 may calculate the demand
in the designated area from the sum of power flows through the fence.
The fence is provided with the measurement device 44, and the
measurement device 44 measures the power flow passing through the
measurement device 44. When the monitoring control device 10 uses
the load value of a one portion instead of a load value of another
portion, a cost reduction can be achieved compared with a case where
the load values are measured for all the portions.
[0057]
In step S4, the demand fluctuation range estimation unit 32 stores
a result of calculating the estimated demand fluctuation range,
by using the setting data D3 stored in step S1 and the demand data
D7 calculated and stored in step S3, as the demand fluctuation range
estimation results data D8.
[0058]
The demand fluctuation range estimation unit 32 calculates the
demand fluctuation range by using the time window as illustrated
in Fig. 7. One or a plurality of designated fluctuation cycles,
corresponding to the time window length, may be set in advance based
30
on the experience of the operator. The demand fluctuation range
estimation unit 32 selects the fluctuation cycle, likely to involve
the deficient adjustment power, from the past adjustment power
determination result, and set the fluctuation cycle as the
designated fluctuation cycle. Thus, the operator can easily
recognize the demand fluctuation range in the fluctuation cycle
that is likely to involve the deficient adjustment power, whereby
a load on the operator for setting the time window can be reduced.
[0059]
In step S5, the correlation estimation unit 33 stores a result of
estimating the correlation between the fluctuation cycle and the
fluctuation range, by using the setting data D3 stored in step S1
and the demand fluctuation range estimation results data D8
calculated and stored in step S4, as the correlation estimation
results data D9. The correlation estimation unit 33 uses the demand
fluctuation range estimation data D8 to compare the demand
fluctuation range with the demand fluctuation range band set in
advance, and may change at least one of the designated fluctuation
cycle and the monitoring time by using at least one of the number
of times or a frequency of a demand fluctuation range being out
of the demand fluctuation range band. The demand fluctuation range
band is defined by a demand fluctuation range upper limit and a
demand fluctuation range lower limit. For example, the correlation
estimation unit 33 reduces the monitoring time, when the number
of times the demand fluctuation range exceeds the demand fluctuation
range upper limit exceeds an upper limit determination times
31
threshold set in advance. Thus, when a sharp fluctuation occurs
in the designated fluctuation cycle, the monitoring control device
10 can determine the shortage of the adjustment power planned value
in a short period of time. For example, the correlation estimation
unit 33 increases the monitoring time, when the number of times
the demand fluctuation range falls below the demand fluctuation
range lower limit exceeds a lower limit determination times
threshold set in advance. Thus, the monitoring control device 10
can reduce the calculation amount, a communication amount, a control
frequency, or the like when the fluctuation in the designated
fluctuation cycle decreases. For example, the correlation
estimation unit 33 may set the fluctuation cycle bandwidth
corresponding to the demand fluctuation range exceeding a demand
fluctuation range threshold as the designated fluctuation cycle
bandwidth.
[0060]
In step S6, the adjustment power determination unit 34 stores, a
result of determining the adjustment power planned value by using
the system facility data D2 and the adjustment power data D4 stored
in step S1, and the correlation estimation results data D9
calculated and stored in step S5, in the adjustment power
determination results data D10. The adjustment power
determination unit 34 determines that the adjustment power planned
value in the adjustable fluctuation cycle is deficient when a
difference of a negative value is obtained by subtracting the demand
fluctuation range in the adjustable fluctuation cycle on the curve
32
corresponding to the correlation in the correlation estimation
results data D9 from the adjustment power planned value in the
adjustable fluctuation cycle in the adjustment power data D4, and
calculates the value of the difference as the shortage amount to
be included in the adjustment power determination results data D10.
[0061]
In step S7 as the final step, the screen display unit 35 causes
the display unit 11 to display one or a plurality of the demand
data D7, the demand fluctuation range estimation results data D8,
the correlation estimation results data D9, and the adjustment power
determination results data D10 for monitoring the state of the power
system 100. For example, the screen display unit 35 causes the
display unit 11 to display an output screen in a formant illustrated
in any one of Fig. 7, Fig. 8, and Fig. 9.
[0062]
The output screen in the format illustrated in Fig. 7 represents
the demand data D7 used by the demand fluctuation range estimation
unit 32. The screen display unit 35 displays the scanning with the
time window for the demand in the designated area on the output
screen with the format illustrated in Fig. 7, whereby the operator
can immediately recognize the period including the demand
fluctuation corresponding to the calculated demand fluctuation
range. The screen display unit 35 may receive the selection of one
of the plurality of designated fluctuation cycles, and may display
on the output screen in the format illustrated in Fig. 7 the time
point at which maximum range of the short-term fluctuation range
33
(demand fluctuation range) is generated within the monitoring
period in the selected designated fluctuation cycle. Thus, the
operator can easily recognize the maximum fluctuation in a desired
fluctuation cycle. The screen display unit 35 may display the
designated area, the system measurement data D1, and the system
facility data D2 on a figure representing the system. Thus, the
operator can easily recognize the designated area corresponding
to the recognized demand data.
[0063]
The output screen with the format illustrated in Fig. 8 indicates
the correlation between the fluctuation cycle and the demand
fluctuation range. Thus, the operator can immediately recognize
the correlation between the fluctuation cycle and the demand
fluctuation range. The output screen with the format illustrated
in Fig. 8 displays at least one of a curve obtained by plotting
the points as the fluctuation cycle and the demand fluctuation range
and the curve obtained by approximating the sets of the fluctuation
cycle and the demand fluctuation range through the least-squares
method. Thus, the operator can immediately recognize the
correlation. The demand fluctuation range estimation unit 32 and
the correlation estimation unit 33 update each of the demand
fluctuation range estimation results data D8 and the correlation
estimation results data D9 once in every monitoring time. On the
output screen with the format illustrated in Fig. 8, the screen
display unit 35 may display the latest correlation estimation
results data D9 and the correlation estimation results data D9
34
obtained by the calculation processing in the past, in an
overlapping manner. Thus, the operator can immediately recognize
the latest change in the correlation. On the output screen with
the format illustrated in Fig. 8, the screen display unit 35 may
display a frequency distribution and a probability density
distribution of a plurality of short term fluctuation ranges
obtained within the monitoring period.
[0064]
The output screen with the format illustrated in Fig. 9 indicates
the shortage of the adjustment power planned value. On the output
screen with the format illustrated in Fig. 9, the screen display
unit 35 displays the adjustment power data D4 and the correlation
estimation results data D9 on the axes representing the fluctuation
cycle and the demand fluctuation range, in an overlapping manner.
Thus, the operator can easily recognize the adjustment amount
shortage. The screen display unit 35 may receive designation of
a certain time point in the past, select the correlation and the
adjustment power planned value at the designated time point, and
display the correlation and the adjustment power planned value thus
selected. Thus, the operator can recognize the shortage of the
adjustment power planned value in the past, and utilize it for the
operation.
[0065]
The CPU 14 may issue an alarm (alert) to the display unit 11 and
the monitoring device, when the calculation cannot be performed
while the calculation processing is in process or when the shortage
35
of the adjustment power planned value is detected.
[0066]
When the power system 100 is interconnected with another power
system via an interconnection line, the storage device of the
monitoring control device 10 may store an interconnection point
restriction data indicating an interconnection point restriction
such as the planned value, the upper limit, the lower limit, and
the like of the power flow on the interconnection line. The
monitoring control device 10 may receive the schedule of the planned
value of the power flow in the designated area, from the central
load-dispatching office or the like. The adjustment power
determination unit 34 determines whether the demand fluctuation
range and the adjustment power planned value satisfies the
interconnection point restriction data. For example, the
adjustment power determination unit 34 may limit the upper limit
and the lower limit of the adjustment power planned value in the
adjustment power data D4 based on the interconnection point
restriction data.
[0067]
The operator may change the adjustment power planned value in the
adjustment power data D4 in accordance with the shortage amount
displayed on the display unit 11, in such a manner that the
adjustment power evaluation value becomes equal to or larger than
the fluctuation range band width in the adjustable fluctuation cycle
with a deficient adjustment power planned value, and input the
changed value to the input unit 12. The adjustment power
36
determination unit 34 may change the adjustment power planned value
in the adjustment power data D4 in accordance with the shortage
amount, in such a manner that the adjustment power evaluation value
becomes equal to or larger than the fluctuation range band width
in the adjustable fluctuation cycle with a deficient adjustment
power planned value. Thus, the monitoring control device 10 can
prevent the shortage of the adjustment power. The adjustment power
determination unit 34 may limit the adjustment power planned value
so that the adjustment power planned value satisfies the
interconnection point restriction data. The adjustment power
determination unit 34 may provide an adjustment power planned value,
as a result of power interchange with the outside of the designated
area, in the adjustment power data D4.
[0068]
The monitoring control device 10 may execute the calculation
processing for a plurality of fluctuation cycles, set some
adjustable fluctuation cycle determined to involve the shortage
of the adjustment power planned value, in the plurality of
fluctuation cycles, as the designated fluctuation cycles, and
execute the calculation processing on the set designated
fluctuation cycle thereafter. Thus, the calculation amount of the
calculation processing can be reduced.
[0069]
In the present embodiment, the demand fluctuation can be recognized
from some measurement values in the power system 100, whereby the
communication cost can be reduced. Even when the correlation
37
between the fluctuation cycle and the demand fluctuation range
changes overtime due to at least one of the change in the output
from a renewable energy generator and a change in the power source
configuration or the system configuration, the shortage amount of
the adjustment power planned value can be recognized with the
correlation between the fluctuation cycle and the demand
fluctuation range estimated, whereby the operator of the power
system can recognize the shortage amount of the adjustable
fluctuation cycle.
[Embodiment 2]
[0070]
The monitoring control device 10 according to the present embodiment
controls output from the power source 110. In the present
embodiment, elements that are the same as or correspond to those
in Embodiment 1 are denoted with the same reference signs, and the
description thereof will be omitted.
[0071]
Fig. 11 illustrates a functional configuration of a monitoring
control device 10b according to Embodiment 2.
[0072]
The monitoring control device 10b includes a system frequency
detection unit 0101 and an output adjustment amount determination
unit 0103, in addition to the elements of the monitoring control
device 10. The monitoring control device 10b includes an
adjustment power determination unit 34b instead of the adjustment
power determination unit 34.
38
[0073]
The system frequency detection unit 0101 detects a system frequency
of the power system 100 interconnected with the power source 110.
The output adjustment amount determination unit 0103 calculates
an output adjustment amount of the power source 110, and issues
an instruction based on the output adjustment amount to the power
source 110, the EMS that controls the power source 110, or the like,
by using the communication unit 13. The instruction may indicate
a target output value obtained by adding the output adjustment
amount to the current output, and may indicate the output adjustment
amount.
[0074]
As in the generally employed technique, the system frequency
detection unit 0101 calculates the system frequency by using the
measurement value from the measurement device 44 coupled to the
power system 100, and calculates a system frequency difference (Δf)
as a difference between the system frequency and a commercial rated
frequency set in advance.
[0075]
The adjustment power determination unit 34b determines an output
adjustment amount lower limit LL and an output adjustment amount
upper limit UL of the power source 110, based on the adjustment
power data D4 set in advance or the adjustment power data D4
corrected after the shortage of the adjustment power has been
determined. For example, the adjustment power determination unit
34b sets the lower limit of the output adjustment amount range
39
indicated by the adjustment power planned value as the output
adjustment amount lower limit LL, and sets the upper limit of the
output adjustment amount range indicated by the adjustment power
planned value as the output adjustment amount upper limit UL.
[0076]
The adjustment power determination unit 34b provides a lower limit
fluctuation cycle TL, a center fluctuation cycle T0, and an upper
limit fluctuation cycle TH of the adjustable fluctuation cycle
bandwidth as a parameter group 0307 of a bandpass filter 0302, based
on the adjustment power data D4.
[0077]
Fig. 12 illustrates a configuration of the output adjustment amount
determination unit 0103.
[0078]
For example, the output adjustment amount determination unit 0103
uses a control block as illustrated in the figure. In the figure,
a system frequency difference (Δf) 0301 is obtained from the system
frequency detection unit 0101. The output adjustment amount
determination unit 0103 calculates the output adjustment amount
(ΔP) 0306 with the system frequency difference 0301 passed through
the bandpass filter 0302, and under the restriction of an output
adjustment amount upper limit (UL) 0304 and an output adjustment
amount lower limit (LL) 0305, based on a first order lag element
0303. A frequency characteristic of the bandpass filter 0302 is
designated with the lower limit fluctuation cycle TL, the center
fluctuation cycle T0, and the upper limit fluctuation cycle TH.
40
[0079]
The output adjustment amount determination unit 0103 obtains the
target output value of the output adjustment amount by adding the
output adjustment amount (ΔP) to the power generation output value
of the current power source 110 corresponding to the output
adjustment amount.
[0080]
In the present embodiment, the output adjustment is performed for
the power source 110 based on the adjustment power planned value,
whereby a stable system frequency can be achieved.
[0081]
Terms used in the description of the present invention are described.
The monitoring control device 10 and the like may be used as a power
system monitoring device. The communication unit 13 and the like
may be used as a communication unit. The storage device, the memory
15, and the like may be used as a storage unit. The CPU 14 and the
like may be used as a calculation unit. The display unit 11 and
the like may be used as a display apparatus . The system measurement
data D1 and the like may be used as measurement data. The system
facility data D2 and the like may be used as configuration data.
The adjustment power planned value and the like may be used as
adjustment power. The adjustment power evaluation value and the
like may be sued as an amount of adjustment power. The designated
fluctuation cycle and the like may be used as a cycle. The
adjustable fluctuation cycle and the like may be used as a designated
fluctuation cycle. The demand fluctuation range and the like may
41
be used as a fluctuation amount. The output adjustment amount and
the like may be used as an adjustment amount.

WE CLAIM:
[Claim 1]
A power system monitoring device comprising:
a communication unit configured to receive measurement data
measured in a power system;
a storage unit configured to store the measurement data, store
configuration data representing a configuration of the power
system, and store adjustment power representing an ability to adjust
output according to a component of a specific cycle among power
fluctuations within a preset designated area within the power
system; and
a calculation unit configured to calculate demand data as time
sequence data on a demand within the designated area based on the
measurement data and the configuration data, calculate a plurality
of fluctuation amounts each indicating a size of a component of
a corresponding one of a plurality of cycles in the demand data,
calculate a correlation between the plurality of cycles and the
plurality of fluctuation amounts, calculate a fluctuation amount
of the specific cycle based on the correlation, and compare the
fluctuation amount of the specific cycle with a size of the
adjustment power of the specific cycle.
[Claim 2]
The power system monitoring device according to claim 1, wherein
the calculation unit is configured to calculate, when the
fluctuation amount of the specific cycle is larger than the size
of the adjustment power of the specific cycle, a shortage amount
44
of the size of the adjustment power of the specific cycle, by
subtracting the size of the adjustment power of the specific cycle
from the fluctuation amount of the specific cycle.
[Claim 3]
The power system monitoring device according to claim 2 , wherein
the measurement data indicates at least one of voltage, current,
and a power flow in the power system,
the configuration data represents a coupling relationship between
a plurality of at least one of a bus, a line, a power source, a
load, a transformer, and an electric appliance in the power system,
and
the calculation unit is configured to calculate a sum of load values
in a plurality of portions in the designated area, based on the
measurement data and the configuration data, as the demand data.
[Claim 4]
The power system monitoring device according to claim 3, wherein
the calculation unit is configured to select, based on data on a
first portion where a load value is unable to be obtained among
the plurality of portions in at least one of the measurement data
and the configuration data, a second portion where the load value
is able to be obtained among the plurality of portions, , and
calculate the sum of the load values in the plurality of portions
by using the load value in the second portion instead of the load
value in the first portion.
[Claim 5]
The power system monitoring device according to claim 1, wherein
45
the calculation unit is configured to detect, for each of the target
cycles of the plurality of cycles, a short term fluctuation range
indicating an amount of fluctuation of the demand data in a time
window having a length based on the target cycle, and calculate
a largest value of a plurality of the short term fluctuation ranges
obtained by scanning a monitoring time set in advance with the time
window, as a fluctuation amount of the target cycle.
[Claim 6]
The power system monitoring device according to claim 5, wherein
the calculation unit is configured to, for the target cycle,
determine whether the fluctuation amount of the target cycle is
out of a fluctuation amount range set in advance, and change the
monitoring time or the target cycle based on a number of times or
a frequency of the fluctuation amount of the target cycle being
determined to be out of the fluctuation amount range.
[Claim 7]
The power system monitoring device according to claim 1, wherein
the calculation unit is configured to calculate the correlation
between the plurality of cycles and the plurality of fluctuation
amounts, by using a least-squares method.
[Claim 8]
The power system monitoring device according to claim 1, wherein
the calculation unit is configured to cause a display apparatus
to display at least one of a plurality of points each indicating
corresponding one of the plurality of cycles and the plurality of
fluctuation amounts, a curve representing the correlation, and the
46
size of the adjustment power.
[Claim 9]
The power system monitoring device according to claim 8, wherein
the calculation unit is configured to cause the display apparatus
to display the correlation and the size of the adjustment power
of the specific cycle in an overlapping manner on a screen with
axes representing a cycle and a fluctuation amount.
[Claim 10]
The power system monitoring device according to claim 8, wherein
the calculation unit is configured to calculate the fluctuation
amount and the correlation each time the monitoring time elapses,
and cause the display apparatus to display the correlation.
[Claim 11]
The power system monitoring device according to claim 10, wherein
the calculation unit is configured to store the correlation in the
storage unit, and cause the display apparatus to display a past
correlation and a latest correlation.
[Claim 12]
The power system monitoring device according to claim 2 , wherein
the calculation unit is configured to change the adjustment power
of the specific cycle based on the shortage amount.
[Claim 13]
The power system monitoring device according to claim 1, wherein
the calculation unit is configured to calculate, based on the
measurement data, a difference of a frequency of the power system
from a frequency set in advance, calculate an adjustment amount
47
of output of the power source based on the adjustment power of the
specific cycle and the difference, and transmit an instruction based
on the adjustment amount to the power source.
[Claim 14]
A power system monitoring method comprising:
receiving measurement data measured in a power system;
storing the measurement data, configuration data representing a
configuration of the power system, and adjustment power
representing an ability to adjust output according to a component
of a specific cycle among power fluctuations within a preset
designated area within the power system;
calculating demand data as time sequence data on a demand within
the designated area based on the measurement data and the
configuration data;
calculating a plurality of fluctuation amounts each indicating a
size of a component of a corresponding one of a plurality of cycles
in the demand data;
calculating a correlation between the plurality of cycles and the
plurality of fluctuation amounts;
calculating a fluctuation amount of the specific cycle based on
the correlation; and
comparing the fluctuation amount of the specific cycle with a size
of the adjustment power of the specific cycle.