Device and method for controlling power system

Patent metadata

Field	Value
Publication number	US-10389133-B2
Application number	US-201615571172-A
Country	US
Kind code	B2
Filing date	Apr 15, 2016
Priority date	May 13, 2015
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

In order to maintain a system frequency within a permissible range under limitations of the output of a power source to be controlled, a calculation device pertaining to a load-frequency-controlling device of the present invention: predicts time-series data indicating the status of individual power sources in a future control period, the prediction being carried out on the basis of system model data, system data, and renewable energy data; calculates, on the basis of power source data, and for each of the power sources, at least any one of a deviation state indicating the degree to which the time-series data deviates from the limitations and/or a surplus state indicating the degree to which the time-series data shows a surplus with respect to the limitations; resolves the deviation state; and calculates the amount of adjustment in the output of each of the power sources, on the basis of the deviation state and the surplus state, under the condition that the total output of the power sources is maintained.

First claim

The invention claimed is:

1. A device for controlling a power system, comprising:
a storage device; and
a central processing unit (CPU) connected to the storage device,
wherein the storage device, with respect to the power system, which includes a renewable energy generator and a plurality of power sources, stores system model data indicating a model of the power system, system data indicating a state of the power system, renewable energy data indicating a past output of the renewable energy generator, and power source data indicating output limitations of each of the plurality of power sources,
wherein the CPU is programmed to
predict a status of individual power sources, of the plurality of power sources, in a future control period, based on the system model data, the system data, and the renewable energy data,
calculate, based on the power source data, and for each of the plurality of power sources, a deviation state indicating a degree to which the time-series data deviates from the output limitations and a surplus state indicating a degree to which the time-series data indicates a surplus with respect to the output limitations,
calculate an amount of adjustment in an output of each of the plurality of power sources, based on the deviation state and the surplus state, under a condition that the deviation state is prevented, and a total power output of the plurality of power sources is maintained; and
output an adjustment command to each of the plurality of power sources, based on the amount of adjustment, to control the output of each of the plurality of power sources such that the total power output of the plurality of power sources is maintained.

2. The device for controlling the power system according to claim 1 ,
wherein the time-series data also indicates an output command value for each power source of the plurality of power sources, and
wherein the output limitations indicate a range of the output command value of the corresponding power source.

3. The device for controlling the power system according to claim 2 ,
wherein the CPU determines, for each power source of the plurality of power sources, whether or not the time-series data deviates from the range, with respect to each power source,
wherein the CPU calculates a deviation state of a deviant power source among the plurality of power sources, the deviant power source being a power source of which the time-series data is determined to deviate from the range, and
wherein the CPU calculates a surplus state of a non-deviant power source among the plurality of power sources, the non-deviant power source being a power source of which the time-series data is determined not to deviate from the range.

4. The device for controlling the power system according to claim 3 ,
wherein the CPU calculates a deviation amount of the time-series data as the deviation state, based on a distance between the boundary value of the range and the time-series data, with respect to the deviant power source, and
wherein the CPU calculates a surplus amount of the time-series data as the surplus state, based on the distance between the boundary value of the range and the time-series data, with respect to the non-deviant power source.

5. The device for controlling the power system according to claim 4 ,
wherein the CPU calculates the deviation amount having a sign indicating a direction of the deviation with respect to the deviant power source, and calculates an amount of adjustment of the output command value by reversing a sign of the deviation amount, and
wherein the CPU calculates the sum of deviation amounts of all deviant power sources as the deviation, and distributes the deviation to the non-deviant power source according to the surplus amount of the non-deviant power source to calculate an amount of adjustment of an output command value of the non-deviant power source.

6. The device for controlling the power system according to claim 5 ,
wherein the CPU selects, as the specific value, data at a time at which greatest deviation from the range occurs, from the time-series data, with respect to the deviant power source, and calculates a value obtained by subtracting the boundary value on the deviation side of the range from the specific value, as the deviation amount,
wherein in a case where the deviation is a positive value, the CPU uses a value obtained by subtracting the maximum value of the time-series data from the upper limit value of the range for the non-deviant power source, as the surplus amount, and
wherein in a case where the deviation is a negative value, the CPU uses a value obtained by subtracting the lower limit value of the range from the minimum value of the time-series data for the non-deviant power source, as the surplus amount.

7. The device for controlling the power system according to claim 3 ,
wherein the CPU calculates a frequency spectrum of the time-series data for each power source,
wherein the CPU detects an influence amount which is a maximum value of the frequency component of the frequency spectrum as a deviation state, for the deviant power source, and detects the frequency of the influence amount as an influence frequency, and
wherein the CPU detects a frequency component of the influence frequency, from the frequency spectrum, as a target amount, for the non-deviant power source, and calculates a surplus amount that decreases with an increase in the target amount, as the surplus state.

8. The device for controlling the power system according to claim 7 ,
wherein the CPU calculates the amount of adjustment of the frequency component of the influence frequency in the frequency spectrum of the deviant power source, under the condition that the influence amount of the influence frequency of the deviant power source is suppressed, and
wherein the CPU calculates the sum of the influence amounts of the influence frequencies of all deviant power sources as the deviation, and distributes the deviation to the non-deviant power source according to the surplus amount of the non-deviant power source to calculate the amount of adjustment of a component of the influence frequency in a frequency spectrum of the non-deviant power source.

9. The device for controlling the power system according to claim 8 ,
wherein the CPU calculates the reciprocal of the target amount as the surplus amount for the non-deviant power source.

10. The device for controlling the power system according to claim 1 ,
wherein the CPU displays at least one of the time-series data, the deviation state, the surplus state, or an amount of adjustment on a display device, for a specific power source among the plurality of power sources.

11. The device for controlling the power system according to claim 10 ,
wherein the storage device stores limitations on a system frequency of the power system, and
wherein the CPU predicts time-series data of a variation of the system frequency in the future control period, based on the system model data, the system data, and the renewable energy data,
wherein the CPU determines whether a deviation of the time-series data of the variation of the system frequency with respect to the limitations on the system frequency is present, and
wherein the CPU displays at least any one of the time-series data of the variation of the system frequency and presence or absence of the deviation of the time-series data of the variation of the system frequency with respect to the limitations on the system frequency, on the display device.

12. A method for controlling a power system comprising:
predicting, with respect to the power system including a renewable energy generator and a plurality of

Assignees

• Hitachi Ltd

Inventors

• Kato Daichi
• Kuroda Eisuke
• Tomobe Osamu
• Yatsu Masahiro

Classifications

• H02J2101/20

  Dispersed power generation using renewable energy sources · CPC title

• G05B19/00

  Program-control systems · CPC title

• H02J3/28

  Arrangements for balancing of the load in networks by storage of energy · CPC title

• H02J3/38 Primary

  Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel · CPC title

• H02J3/383 Primary

  Electricity · mapped topic