JP2010259154A - Power control apparatus and method of controlling reactive power - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a power control apparatus that reduces the cost required to suppress the ripple of a system voltage when a distributed power supply, which generates electricity by natural energy, is connected to the power system. <P>SOLUTION: An electric power generation predictor 5 is connected to predict an effective electric energy that the distributed power supply 3 can supply at future time, based on information about weather prediction. The predicator compares the effective electric energy forecasted at future time with the present effective electric energy. When determing that the effective electric energy increases at future time, the predicator increases the reactive power setting reactive electric energy that the distributed power supply 3 supplies to the set target value of reactive power, so that it may amount to a rise in a system voltage that is equivalent to an amount of rise in the system voltage estimated by an increase in the effective electric energy, in several seconds to several minutes. After the reactive electric energy reaches the target value of the reactive power, it decreases the reactive electric energy among with an increase in the active electric energy. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a power supply control device and a reactive power control method for performing reactive power control of a small-scale power generation facility that generates power by natural energy such as solar power generation or wind power generation connected to an electric power system.

  When a small-scale power generation facility (hereinafter referred to as “distributed power source”) that uses natural energy, such as solar power generation or wind power generation, is connected to the power system, the amount of effective power supplied by the distributed power source suddenly increases due to changes in weather conditions. Accordingly, the voltage of the power system (hereinafter referred to as “system voltage”) fluctuates.

  On the other hand, the system voltage also fluctuates due to a change in power demand due to load fluctuations at the consumer end. Normally, the system voltage tends to decrease during daytime heavy loads, and the system voltage increases during light loads at midnight. In order to suppress such gradual fluctuations in the system voltage due to load fluctuations at the consumer end, either install a transformer with tap switching at load at the substation or the middle of the distribution line, or use a switch type power capacitor or distribution A phase adjusting device such as a road reactor is installed to control the amount of reactive power, and fluctuations in the system voltage are suppressed directly or indirectly.

  However, control of the system voltage by a phase-adjusting device such as a transformer with a tap changer at load, a switch-type power capacitor, or a shunt reactor is slow in operating speed, so the effective power supplied by the distributed power source due to changes in weather conditions It is difficult to suppress fluctuations in the system voltage when the quantity changes rapidly. For this reason, conventionally, power electronics equipment such as SVC (Static Var Compensator), which is a phase adjustment device capable of high-speed operation, is installed at the middle point of the distribution line, or the distributed power supply is disabled By supplying power, fluctuations in the system voltage are suppressed.

  As an example in which the distributed power source supplies reactive power, the variable-speed wind power generation system disclosed in Patent Document 1 below includes reactive power control means that controls reactive power based on a reactive power command. A technology is disclosed that can determine the amount of reactive power independently of the amount, can output a large amount of reactive power even when the generated power is small, and can realize a reactive power output according to system conditions.

JP 2008-11607 A

  However, power electronics equipment such as SVC that can suppress rapid fluctuations in system voltage is expensive. In addition, in the technique disclosed in Patent Document 1, in addition to the active power amount supplied by the distributed power source, a reactive power amount corresponding to a system condition such as the size of a load connected to the power system or a load change is assumed. Therefore, it is necessary to increase the power capacity. As described above, the conventional technique has a problem that the cost for suppressing the fluctuation of the system voltage is increased.

  The present invention has been made in view of the above, and in the case where a distributed power source that generates power by natural energy is connected to an electric power system, it is possible to reduce the cost required to suppress fluctuations in the system voltage. It is an object of the present invention to obtain a power control device and a reactive power control method.

  In order to solve the above-described problems and achieve the object, the present invention is connected to a power system including a voltage control device that suppresses fluctuations in system voltage, and supplies power generated by natural energy to the power system. A power supply control device that performs reactive power control of a distributed power source, and connected to a power generation amount prediction device that predicts an active power amount that can be supplied by the distributed power source at a previous time based on weather prediction, and at a current time The active power supplied by the distributed power source is detected, and the active power expected at the previous time is compared with the active power at the current time to determine that the active power increases at the previous time. In this case, in a few seconds to a few minutes, the distributed power up to the reactive power target value set so as to increase the system voltage equivalent to the increase in the system voltage expected due to the increase in the amount of active power. Source increases the amount of reactive power which is supplied, after the reactive energy has reached the reactive power target value, and decreases the amount of reactive power with increasing active power.

  According to the present invention, when it is determined that the active power amount increases at the previous time, the generated power amount increases in a slow time of about several seconds to several minutes that the voltage control by the voltage control device can follow. By increasing the amount of reactive power supplied by the distributed power source to the reactive power target value set to increase the system voltage equivalent to the increase in system voltage expected by Be prepared for the rise. Then, after the reactive power reaches the reactive power target value, the reactive power is decreased in accordance with the increase in the active power, so that the increase in the system voltage due to the increase in the active power is absorbed, and the system voltage is reduced. Since the voltage is maintained within a predetermined appropriate voltage range, by coordinating the reactive power control of the distributed power source and the voltage control by the voltage control device, fluctuations in the system voltage accompanying an increase in the amount of active power can be suppressed. . Therefore, a high-speed phase adjusting device such as SVC for suppressing rapid fluctuations in the system voltage becomes unnecessary. In addition, the distributed power source only has to supply in advance a reactive power amount that is set to increase the system voltage equivalent to the increase in the system voltage expected due to an increase in the active power amount. It is not necessary to increase the power capacity of the distributed power source in order to supply reactive power exceeding the rated value of active power. In this way, when a distributed power source that generates power by natural energy is connected to the power system, it is possible to reduce the cost required to suppress fluctuations in the system voltage accompanying an increase in the amount of active power. Play.

FIG. 1 is a diagram illustrating an example of a power system including a distributed power source to which the power control device according to the first embodiment is connected. FIG. 2 is a diagram illustrating an example of the relationship between the change in the amount of generated power and the time transition. FIG. 3 is a flowchart of an example of a processing procedure of the power supply control apparatus according to the first embodiment. FIG. 4 is a diagram of an example of a power system including a distributed power source to which the power control device according to the second embodiment is connected. FIG. 5 is a flowchart of an example of a processing procedure of the power supply control apparatus according to the second embodiment.

  Embodiments of a power supply control device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating an example of an electric power system including a distributed power source to which the power control device according to the first embodiment is connected.

  First, the configuration of the power system including the distributed power source to which the power supply control device according to the first embodiment is connected and the schematic functions of each unit will be described with reference to FIG. In FIG. 1, a power system 1 includes a voltage control device 2 and a distributed power source 3. The distributed power supply 3 is connected to the power supply control device 4 according to the first embodiment, and the power supply control device 4 is connected to the power generation amount prediction device 5.

  The voltage control device 2 assumes that it responds to a relatively gradual change in system voltage due to a change in a load (not shown) connected to the consumer end, and a load-type tap-switching transformer or switch-type power. It is composed of inexpensive and slow operating devices such as a phase adjusting device such as a condenser or a shunt reactor. When the system voltage increases, the voltage control device 2 decreases the system voltage so that it falls within a predetermined appropriate voltage range after the set time delay, and conversely, when the system voltage decreases, the voltage control device 2 decreases the set time delay. Later, voltage control is performed to increase the system voltage so as to be within a predetermined appropriate voltage range.

  The distributed power source 3 supplies active power generated by natural energy such as wind power and solar power (hereinafter referred to as “generated power”) to the power system 1 and based on instructions from a power supply control device 4 to be described later. 1 has a function of generating reactive power from AC power supplied from 1 and supplying it to the power system 1. In FIG. 1, one distributed power source 3 is illustrated for convenience of explanation, but a plurality of distributed power sources 3 may be installed in the power system 1.

  The power generation amount prediction device 5 predicts a power generation active power amount based on weather prediction information such as wind speed and sunshine input from the outside, and outputs an effective power amount prediction value. In addition, about the prediction means of the electric power generation effective electric energy, it is realizable by a well-known technique.

  The power supply control device 4 controls the reactive power supplied by the distributed power source 3 based on the active power prediction value output from the power generation prediction device 5 and the power generation active power at the time when the active power prediction value is output. (Hereinafter simply referred to as “reactive power control”). The reactive power control of the distributed power supply 3 by the power supply control device 4 will be described later.

  Here, the concept of the first embodiment according to the present invention will be described. Generally, when the load at the consumer end increases, the system voltage decreases. Conversely, when the load at the consumer end decreases, the system voltage increases. When the distributed power source 3 is not included in the power system 1, the fluctuation of the system voltage is a relatively gradual fluctuation due to the fluctuation of the load connected to the consumer end. Even with slow control, it is possible to keep the system voltage within a predetermined appropriate voltage range.

  However, when the distributed power source 3 is connected to the power system 1, the amount of active power generated by the distributed power source 3 varies due to changes in weather conditions, and the associated system voltage variation is connected to the consumer end. Therefore, voltage control by the voltage control device 2 cannot follow, and the system voltage may fluctuate greatly and deviate from a predetermined appropriate voltage range. That is, in FIG. 1, when the active power generation amount supplied by the distributed power source 3 increases rapidly due to changes in weather conditions, the voltage control by the voltage control device 2 is not in time, and the system voltage rapidly increases.

  Therefore, in the first embodiment, when an increase in the power generation active power amount due to changes in weather conditions is predicted, the distributed power source 3 supplies the reactive power in advance, and the reactive power amount is subjected to voltage control by the voltage control device 2. By gradually increasing in a slow time of several seconds to a few minutes that can be followed, the system voltage is kept within the predetermined appropriate voltage range, in preparation for an increase in system power generation due to an increase in active power generation, When the active power amount increases, the reactive power amount supplied in advance is decreased in accordance with the increase in the generated active power amount, thereby suppressing fluctuations in the system voltage and keeping the system voltage in a predetermined appropriate voltage range. That is, by providing reactive power in advance before the active power generation actually increases, the voltage control device 2 has a margin for performing control to reduce the system voltage, thereby increasing the power generation active power amount. Absorbs sudden rises in system voltage.

  Next, an outline of reactive power control of the distributed power supply 3 by the power supply control device 4 will be described with reference to FIGS. 1 and 2. FIG. 2 is a diagram illustrating an example of the relationship between the change in the amount of generated power and the time transition.

  The power generation amount prediction device 5 predicts a power generation active power amount at a time earlier than the current time based on weather prediction information (see FIG. 2), and outputs a predicted value of active power amount. The power supply control device 4 measures the power generation active power amount at the current time (see FIG. 2), compares the power generation active power amount at the current time with the predicted active power amount, and generates the current power generation from the predicted active power amount. When the value obtained by dividing the active power amount is larger than a predetermined threshold, the system is expected to increase due to the increase in the generated active power amount in a slow time of several seconds to several minutes in which the voltage control by the voltage control device 2 can follow. The reactive power amount supplied by the distributed power source 3 is increased to the reactive power target value set so as to increase the system voltage equivalent to the voltage increase. That is, the control for increasing the reactive power amount is started when it is predicted that the increase in the generated power amount is large at the previous time. After the reactive power amount reaches the reactive power target value, when the weather conditions actually change and the generated active power amount increases, the power supply control device 4 supplies in advance in accordance with the increase in the generated active power amount. Reduce reactive power. Note that the amount of reactive power supplied by the distributed power source 3 may be supplied in an amount that allows for an increase in system voltage due to an increase in the amount of generated power. That is, the reactive power amount becomes zero after a certain amount of time has elapsed since the power generation active power amount actually increased at the previous time. Further, in a state where the power generation active power amount is stable, the system voltage is kept constant by voltage control by the voltage control device 2, so that the distributed power source 3 does not need to supply reactive power.

  Next, a processing procedure of reactive power control of the distributed power source 3 by the power source control device 4 will be described with reference to FIG. FIG. 3 is a flowchart of an example of a processing procedure of the power supply control apparatus according to the first embodiment. In FIG. 3, the initial setting operation of the power supply control device 4 is performed in the processing of step ST101 to step ST102, and the system voltage maintaining operation is performed in the processing of step ST103 to step ST110.

  First, the power supply control device 4 measures the reactive power amount currently supplied by the distributed power source 3, stores the measured reactive power amount as Q1 (step ST101), and sets the reactive power target value Qset to Q1. A value is set (step ST102).

  When the system voltage maintaining operation is started, the power supply control device 4 measures the power generation active power amount currently supplied by the distributed power source 3, and stores the measured power generation active power amount as P1 (step ST103). . Next, the active power amount prediction value at the previous time after the elapse of time T is input from the power generation amount prediction device 5, and the active power amount prediction value is stored as P2 (step ST104). Is compared with the power generation active power amount P1 at step ST105.

  Here, if the value of P2-P1 is smaller than the predetermined threshold value δ (No in step ST105), it is determined that the increase in the system voltage due to the increase in the amount of generated power is small, and the process returns to step ST103. . When the value of P2−P1 is larger than the predetermined threshold value δ (step ST105, Yes), it is determined that the increase of the system voltage due to the increase of the generated active power amount is large, and the value of the predicted active power amount P2 is set. Accordingly, reactive power target value Qset is reset (step ST106). Here, the value obtained by multiplying the value of P2−P1 by the proportionality coefficient α and adding the previously set Qset is set as a new reactive energy target value Qset. The proportional coefficient α is a value that varies depending on the power system 1 and is a value set by the operator.

  In preparation for an increase in the power generation active power amount, the power supply control device 4 performs control so that the reactive power amount supplied by the distributed power source 3 gradually increases by ΔQ until reaching the value of Qset set in step 106 (step ST107). ). ΔQ is a value that varies depending on the power system 1 and is set to a value that can be followed by voltage control by the voltage control device 2.

  When the reactive power amount reaches the reactive power amount target value Qset, the power supply control device 4 measures the power generation active power amount at that time and stores the measured power generation active power amount as PA1 (step ST108). Control is performed so that the amount of reactive power is reduced by a value obtained by multiplying the value of P1 by a proportional coefficient β (step ST109). The proportional coefficient β is a value that varies depending on the power system 1 and is a value set by the operator.

  Then, it is determined whether or not the time T has elapsed from the time when the power generation amount prediction device 5 outputs the predicted active power amount P2 (step ST110). If the time T has not elapsed (step ST110, No), By repeatedly executing the processing from step ST108 to step ST109, the amount of reactive power supplied in advance is reduced in accordance with the increase in the amount of active power generation. When time T elapses (step ST110, Yes), the processing returns to step ST103, and the processing from step ST103 to step ST109 is repeatedly executed.

  In the above processing procedure, the processing of step ST106 to step ST107 prepares for the increase of the system voltage due to the increase of the power generation active power amount after the lapse of time T, and then the processing of step ST108 to step ST110 determines the power generation active power amount Absorbs increase in system voltage due to increase.

  As described above, according to the power supply control device of the first embodiment, when it is predicted that the power generation active power amount will increase at the previous time, the voltage control by the voltage control device can be followed for several seconds to several minutes. The reactive power supplied by the distributed power source is increased to the reactive power target value set to increase the system voltage equivalent to the increase in the system voltage expected due to the increase in the generated power This prepares for an increase in system voltage due to an increase in the amount of active power generation. Then, after the reactive power reaches the reactive power target value, the reactive power is decreased in accordance with the increase in the generated power, thereby absorbing the increase in the system voltage due to the increase in the generated power. Since the voltage is maintained within a predetermined appropriate voltage range, the reactive power control of the distributed power supply by the power supply control device according to the first embodiment and the voltage control by the voltage control device are coordinated to increase the amount of active power generation. It is possible to suppress the fluctuation of the system voltage accompanying the. Therefore, a high-speed phase adjusting device such as SVC for suppressing rapid fluctuations in the system voltage becomes unnecessary. In addition, since the distributed power source only has to supply in advance a reactive power amount that is set to increase the system voltage equivalent to the increase in the system voltage expected due to an increase in the generated active power amount. There is no need to increase the power capacity of the distributed power source to supply reactive power that exceeds the value. In this way, when a distributed power source that generates power using natural energy is connected to the power system, it is possible to reduce the cost required to suppress fluctuations in the system voltage accompanying an increase in the amount of active power generation.

  In addition, according to the reactive power control method of the first embodiment, the active power generation amount that can be supplied by the distributed power source at the previous time is predicted based on the weather forecast, and the power generation effective power that the distributed power source supplies at the current time is predicted. When the amount of power generated is detected, the amount of active power generated at the previous time is compared with the amount of active power generated at the current time, and the amount of generated power is predicted to increase at the previous time, the voltage generated by the voltage control device Distributed to the reactive power target value that is set to increase the system voltage equivalent to the increase in system voltage expected due to the increase in the amount of active power generation in a slow time of several seconds to several minutes that can be followed by control Increase the amount of reactive power supplied by the power supply. Then, after the reactive power reaches the reactive power target value, the reactive power is decreased as the generated active power is increased to absorb the increase in the system voltage due to the increase in the generated power. Since the reactive power control method of the first embodiment and the voltage control by the voltage control device are coordinated with each other, the fluctuation of the system voltage accompanying the increase in the amount of generated power is suppressed. can do. Therefore, a high-speed phase adjusting device such as SVC for suppressing rapid fluctuations in the system voltage becomes unnecessary. In addition, since the distributed power source only has to supply in advance a reactive power amount that is set to increase the system voltage equivalent to the increase in the system voltage expected due to an increase in the generated active power amount. There is no need to increase the power capacity of the distributed power source to supply reactive power that exceeds the value. In this way, when a distributed power source that generates power using natural energy is connected to the power system, it is possible to reduce the cost required to suppress fluctuations in the system voltage accompanying an increase in the amount of active power generation.

Embodiment 2. FIG.
In the first embodiment, the case where the power generation active power amount supplied from the distributed power source 3 increases has been described. In the second embodiment, the case where the power generation active power amount decreases will be described. When the amount of active power generated by the distributed power supply rapidly decreases due to changes in weather conditions, voltage control by the voltage control device is not in time, and the system voltage rapidly decreases. Therefore, in the second embodiment, when the power generation active power amount decreases, the distributed power supply supplies the reactive power necessary to compensate for the decrease in the system voltage accompanying the decrease in the power generation active power amount. By absorbing the sudden drop in the system voltage due to the decrease in the electric energy and then reducing the reactive power in a slow time of several seconds to several minutes that can be followed by the voltage control by the voltage control device, The fluctuation is suppressed and the system voltage is kept within a predetermined appropriate voltage range. In other words, the decrease in the system voltage due to the decrease in the power generation active power amount is absorbed by the distributed power supply once supplying the reactive power, and then the reactive power amount is decreased with the voltage control device maintaining the system voltage. .

  FIG. 4 is a diagram of an example of a power system including a distributed power source to which the power control device according to the second embodiment is connected. In addition, the same code | symbol is attached | subjected to the component which is the same as that of Embodiment 1, or equivalent, and the detailed description is abbreviate | omitted.

  First, the configuration of the power system including the distributed power source to which the power source control device according to the second embodiment is connected and the schematic functions of each unit will be described with reference to FIG. In FIG. 4, the power system 1 includes a voltage control device 2 and a distributed power source 3. The distributed power supply 3 is connected to the power supply control device 4a according to the second embodiment. In the second embodiment, unlike the first embodiment, the power generation amount prediction device is not used. Therefore, the power generation amount prediction device is not shown for convenience of explanation, but the power generation amount prediction device is provided as in the first embodiment. Of course, it's also good.

  Next, an outline of reactive power control of the distributed power supply 3 by the power supply control device 4a will be described with reference to FIG.

  The power supply control device 4a measures the power generation active power amount at predetermined time intervals, compares the previous power generation active power amount with the current power generation active power amount, and compares the current power generation active power amount with the current power generation active power amount. When the value obtained by dividing the amount is larger than a predetermined threshold, the reactive power amount supplied by the distributed power source 3 is increased to the reactive power target value that compensates for the decrease in the system voltage due to the decrease in the generated active power amount. Then, after the reactive power amount reaches the reactive power target value, the reactive power amount is decreased in a slow time of several seconds to several minutes in which the voltage control by the voltage control device 2 can follow. Note that the reactive power amount supplied by the distributed power source 3 may be supplied to compensate for the decrease in the system voltage due to the decrease in the generated active power amount. That is, after a certain amount of time has elapsed since the reactive power amount has gradually decreased, the reactive power amount becomes zero. Further, in a state where the power generation active power amount is stable, the system voltage is kept constant by voltage control by the voltage control device 2, so that the distributed power source 3 does not need to supply reactive power.

  Next, a processing procedure of reactive power control of the distributed power source 3 by the power source control device 4a will be described with reference to FIG. FIG. 5 is a flowchart of an example of a processing procedure of the power supply control apparatus according to the second embodiment. In FIG. 5, the initial setting operation of the power supply control device 4a is performed in the processing of step ST201 to step ST203, and the system voltage maintaining operation is performed in the processing of step ST204 to step ST209.

  First, the power supply control device 4a measures the power generation active power amount and the reactive power amount currently supplied by the distributed power source 3, and stores the power generation active power amount as P1 and the reactive power amount as Q1 (step ST201). Then, the value of Q1 is set to the reactive energy target value Qset (step ST202). Then, in consideration of the time required for voltage control by the voltage control device 2, a processing time T for performing the processing of step ST204 to step ST209 is set (step ST203).

  When the system voltage maintaining operation is started, the power supply control device 4a stores the previous power generation active power amount P1 as P2 (step ST204). Next, the power generation active power currently supplied by the distributed power source 3 is measured and stored as P1 (step ST205), and the previous power generation active power P2 is compared with the current power generation active power P1 (step ST205). Step ST206).

  Here, when the value of P2-P1 is smaller than the predetermined threshold value δ (step ST206, No), it is determined that the decrease in the system voltage due to the decrease in the power generation active energy is small, and the process proceeds to step ST208. When the value of P2−P1 is larger than the predetermined threshold value δ (step ST206, Yes), it is determined that the decrease of the system voltage due to the decrease of the generated active power amount is large, and the value of the predicted active power amount P2 is set. Accordingly, reactive power target value Qset is reset (step ST207). Here, the value obtained by multiplying the value of P2−P1 by the proportionality coefficient α and adding the previously set Qset is set as a new reactive energy target value Qset. Note that the proportionality coefficient α is a value set by the operator, and a value obtained by multiplying the value of P2−P1 by the proportionality coefficient α (that is, an increase in Qset) causes a decrease in system voltage due to a decrease in the amount of generated power. It is set so that the amount of reactive power required to compensate is obtained.

  Then, the power supply control device 4a performs control so that the reactive power amount supplied by the distributed power source 3 becomes the reactive power target value Qset set in step ST207 (step ST208).

  When the reactive power amount reaches the reactive power amount target value Qset, the power supply control device 4a performs control so that the value of Qset is decreased by ΔQ and the reactive power amount becomes the value of Qset (step ST209). ΔQ is a value that varies depending on the power system 1 and is set to a value that can be followed by voltage control by the voltage control device 2.

  And it returns to the process of step ST204 and repeats the process of step ST204-step ST209.

  In the above processing procedure, the reduction of the system voltage due to the reduction of the generated active power amount is absorbed by the processing of step ST207 to step ST208, and the reactive power amount is gradually reduced by the subsequent step ST209. That is, by repeatedly executing the processing of step ST204 to step ST209 at the time interval of the processing time T, the reactive power amount is reduced while the voltage control device 2 maintains the system voltage.

  As described above, according to the power supply control device of the second embodiment, when the amount of generated power is reduced, the distributed power supply is reduced to the reactive power target value that compensates for the decrease in the system voltage due to the decrease in the amount of active power. By increasing the amount of reactive power to be supplied, a rapid decrease in system voltage due to a decrease in the amount of generated power is absorbed. After that, by reducing the reactive energy in a slow time of several seconds to several minutes that can be followed by voltage control by the voltage control device, the fluctuation of the system voltage is suppressed and the system voltage is kept within a predetermined appropriate voltage range. As described above, by coordinating the reactive power control of the distributed power supply by the power supply control device according to the second embodiment and the voltage control by the voltage control device, fluctuations in the system voltage accompanying an increase in the amount of generated power can be suppressed. be able to. Therefore, a high-speed phase adjusting device such as SVC for suppressing rapid fluctuations in the system voltage becomes unnecessary. In addition, the distributed power supply only needs to supply reactive power that is sufficient to compensate for the decrease in system voltage due to the decrease in generated power, so that reactive power exceeding the rated value of generated power can be supplied. There is no need to increase the power capacity of the distributed power source. In this way, when a distributed power source that generates power using natural energy is connected to the power system, it is possible to reduce the cost required to suppress fluctuations in the system voltage accompanying a decrease in the amount of generated power.

  In addition, according to the reactive power control method of the second embodiment, the power generation active power supplied by the distributed power source is detected at predetermined time intervals, the power generation active power detected last time, the power generation active power detected this time, , The reactive power supplied by the distributed power source is increased to the reactive power target value that compensates for the decrease in the system voltage due to the decrease in the generated power. . Then, after the reactive power amount reaches the reactive power target value, the reactive power amount is decreased in a slow time of about several seconds to several minutes that can be followed by the voltage control by the voltage control device, thereby generating the active power amount. Since the system voltage is kept within a predetermined appropriate voltage range by absorbing the rapid decrease of the system voltage due to the decrease of the system voltage and suppressing the fluctuation of the system voltage, the reactive power control method and voltage control apparatus of the second embodiment By coordinating with the voltage control by, it is possible to suppress fluctuations in the system voltage accompanying an increase in the amount of active power generation. Therefore, a high-speed phase adjusting device such as SVC for suppressing rapid fluctuations in the system voltage becomes unnecessary. In addition, the distributed power supply only needs to supply reactive power that is sufficient to compensate for the decrease in system voltage due to the decrease in generated power, so that reactive power exceeding the rated value of generated power can be supplied. There is no need to increase the power capacity of the distributed power source. In this way, when a distributed power source that generates power using natural energy is connected to the power system, it is possible to reduce the cost required to suppress fluctuations in the system voltage accompanying a decrease in the amount of generated power.

  In the above embodiment, the respective processing procedures when the increase in the power generation active power amount due to the change in weather conditions is predicted and when the power generation active power amount decreases are described based on different flowcharts. It is possible to combine them into one processing procedure, and it is possible to operate two processing procedures in parallel.

  The configurations described in the above embodiments are examples of the configurations of the present invention, and can be combined with other known techniques, and a part of the configurations is omitted without departing from the gist of the present invention. Needless to say, it is possible to change the configuration.

  Furthermore, in the embodiment, the invention content is described for a distributed power source that generates power by natural energy such as sunlight and wind power connected to the power system, but the application field is not limited to this, It goes without saying that it can be applied to various power generation facilities that generate power using natural energy.

  As described above, the power supply control device according to the present invention is useful as an invention that can suppress fluctuations in the system voltage when a distributed power source that generates power using natural energy is connected to the power system. This is suitable for reducing the cost required to suppress voltage fluctuation.

DESCRIPTION OF SYMBOLS 1 Electric power system 2 Voltage control apparatus 3 Distributed type power supply 4, 4a Power supply control apparatus 5 Power generation amount prediction apparatus

Claims (4)

A power supply control device that is connected to a power system including a voltage control device that suppresses fluctuations in system voltage and performs reactive power control of a distributed power source that supplies power generated by natural energy to the power system,
A power generation amount prediction device that predicts the amount of active power that can be supplied by the distributed power source at a previous time based on weather prediction is connected,
The active power supplied by the distributed power source at the current time is detected, and the active power expected at the previous time is compared with the active power at the current time, and the active power increases at the previous time. If this is determined, the distributed power supply is supplied to the reactive power target value that is set to increase the system voltage equivalent to the increase in the system voltage expected due to the increase in active power in seconds to minutes. The reactive power amount is increased, and after the reactive power amount reaches the reactive power target value, the reactive power amount is decreased as the active power amount increases. A power supply control device that is connected to a power system including a voltage control device that suppresses fluctuations in system voltage and performs reactive power control of a distributed power source that supplies power generated by natural energy to the power system,
When the active power supplied by the distributed power source is detected at a predetermined time interval, the active power detected last time is compared with the active power detected this time, and it is determined that the active power has decreased. , Increase the reactive power supplied by the distributed power source to the reactive power target value that compensates for the decrease in the system voltage due to the reduction of the active power, and after the reactive power reaches the reactive power target value, from a few seconds A power supply control device that reduces the amount of reactive power in a few minutes. A reactive power control method for a distributed power source that is connected to a power system including a voltage control device that suppresses fluctuations in the system voltage and supplies power generated by natural energy to the power system,
Predicting the amount of active power that the distributed power supply can supply at a previous time based on weather prediction; and
Detecting the amount of active power supplied by the distributed power source at the current time;
Comparing the active power amount predicted at the previous time with the active power amount at the current time;
When it is determined that the amount of active power increases at the previous time,
In a few seconds to several minutes, the reactive power supplied by the distributed power source is increased to the reactive power target value set to increase the system voltage equivalent to the increase in system voltage expected by the increase in active power. Steps,
After the reactive power reaches the reactive power target value, the reactive power is decreased as the active power increases; and
A reactive power control method comprising: A reactive power control method for a distributed power source that is connected to a power system including a voltage control device that suppresses fluctuations in the system voltage and supplies power generated by natural energy to the power system,
Detecting active energy supplied by the distributed power source at predetermined time intervals;
Comparing the previously detected active energy amount with the currently detected active energy amount;
When it is determined that the amount of active power has decreased,
Increasing the amount of reactive power supplied by the distributed power source to a reactive power target value that compensates for a decrease in system voltage due to a decrease in active power amount;
Reducing the reactive energy in seconds to minutes after the reactive energy reaches the reactive power target value; and
A reactive power control method comprising:

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