JP2019140898A - Reactive power compensation device and control program thereof, and reactive power compensation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously detect a dead band width of a voltage deviation based on a cycle deviation of a system voltage and to perform reactive power compensation according to a voltage deviation having this dead band, thereby detecting an active isolated operation of a distributed power supply A reactive power compensator that does not interfere with the above, a control program therefor, and the like are provided. In a reactive power compensator 100 that is connected to a power system together with a distributed power source 200 having an active islanding detection function, an AC control unit 100A calculates a system voltage period calculation unit 111 and a period deviation. Independent operation non-interference control including a cycle deviation detection unit 112 for detecting, a dead band width setting unit 113 for setting a dead band width according to the cycle deviation, and a voltage deviation calculation unit 114 for calculating a deviation between a system voltage and a target voltage according to the dead band width. And a voltage controller 140 for sequentially generating a reactive current command and a voltage command based on the voltage deviation to control the power converter INV, a coordinate converter 160, a current controller 180, and a PWM circuit. It is equipped with 190 and the like. [Selection diagram] Figure 2

Description

The present invention relates to a reactive power compensator and the like that controls a voltage at a connection end to a power system to a target voltage by injecting reactive power into the power system from a power converter connected to the power system.
Specifically, a static reactive power compensator such as an SVC (Static Var Compensator) or a STATCOM (Static Synchronous Compensator) that does not interfere with an active islanding detection function of a distributed power source connected to an electric power system and its The present invention relates to a control program and a reactive power compensation system including a reactive power compensation device and a distributed power source.

FIG. 11 is a configuration diagram of a conventional static reactive power compensator (SVC). The principle of this reactive power compensator is described in Patent Document 1, for example.
In FIG. 11, the reactive power compensator 100 ′ includes a power converter INV such as an inverter connected to the power system 1 via a circuit breaker CB and a transformer Tr, and an AC control unit 100A ′ as its control means. I have. AC to the control unit 100A ', is input and the system voltage v _r detected by the output current and voltage detector VT of the power converter INV detected by the current detector CT, based on the input information and the target voltage 130 The voltage command V ^* is calculated, and the semiconductor switching element of the power converter INV is controlled by a drive pulse generated by a PWM (pulse width modulation) circuit 190 according to the voltage command V ^* .

Next, the configuration and operation of the AC control unit 100A ′ will be briefly described.
The difference dv between the amplitude value and the target voltage 130 of the system voltage _{v r} which is calculated by the amplitude calculating unit 121 obtained by the subtractor 101, the voltage control unit so that this deviation dv is zero (AVR) 141 are reactive current command I _qref is calculated. Here, it goes without saying that a reactive power command may be used instead of the reactive current command I _qref .

On the other hand, calculates the phase θ by entering the system voltage v _r in the three-phase PLL circuit 150, calculates a reactive current command of the three-phase coordinate conversion unit 160 performs AC-DC conversion and inverse conversion by using the phase θ To do. The subtractor 102 obtains a current deviation dC between the three-phase reactive current command and the output current (reactive part) of the reactive power compensator 100 ′, and the current control unit (ACR) 180 makes the current deviation dC zero. Operates to calculate the compensation voltage ΔV.
Also, 'with seeking, these compensation voltage [Delta] V, [Delta] V' transformer voltage compensator 170 based on the reactive current command output from the coordinate conversion unit 160 is the compensation voltage [Delta] V between the system voltage v _r and the adder 103, was added by 104 produces a voltage command V ^*, by controlling the power converter INV gives the voltage command V ^* to the PWM circuit 190, the connection end of the power system 1 of the reactive power compensator 100 ' The voltage is controlled to the target voltage 130.

FIG. 12 is an operation explanatory diagram when the reactive power compensator 100 ′ is linked to the commercial power system.
As shown in FIG. 12A, when the voltage at the connection end decreases due to load application or the like, the reactive power compensator 100 ′ injects the advanced reactive power into the power system 1 to suppress the voltage decrease. Also, as shown in FIG. 12 (b), when the voltage of the power system rises due to a load drop or the like, the reactive power compensator 100 ′ injects delayed reactive power to suppress the voltage rise, and the target Maintain voltage.
12A and 12B show the case where reactive power is injected, this reactive power may be replaced with reactive current.

On the other hand, not only a load but also a distributed power source such as a generator is connected to the commercial power system.
When an accident occurs in the power system, the circuit breaker or switch in the system operates to disconnect the accident section from the system. If a distributed power source is connected to the disconnected accident section, the distributed power source The single operation state occurs. From the viewpoint of preventing an electric shock in such a case and preventing accidents during reclosing, it is prescribed that the distributed power source has an isolated operation detection function for detecting an isolated operation state and disconnecting from the power system.

Here, as a method in which the distributed power source actively detects a single operation, for example, the reactive power fluctuation method and the reactive power compensation method described in P.152-153 of Non-Patent Document 1 are known.
In the reactive power fluctuation method, the reactive power injected into the power system is periodically changed by periodically changing the voltage setting value of the automatic voltage regulator (AVR) of the distributed power source (synchronous generator or the like). This is a method of detecting frequency fluctuations that occur after the transition to isolated operation.
The reactive power compensation method is the same as the reactive power fluctuation method in principle, but the reactive power injected into the power system from the reactive power adjustment device provided in the distributed power source is periodically changed. This is a method of detecting frequency fluctuations that occur after the transition to isolated operation.

  However, as shown in FIG. 13, when the reactive power compensator 100 ′ described above is connected to the power grid 1 together with the distributed power source 200 and the load 300, the reactive power compensation apparatus 100 ′ is invalid when the circuit breaker CB is opened due to a system fault. When the operation of the power compensation device 100 ′ and the distributed power source 200 is continued, the above-described isolated operation detection function of the distributed power source 200 may be hindered by the operation of the reactive power compensation device 100 ′.

For example, FIG. 14 shows an operation waveform when the reactive power fluctuation method described above is adopted as the isolated operation detection method of the distributed power source 200.
In this reactive power fluctuation method, the frequency deviation (difference between the system voltage frequency of the past several cycles and the current frequency) that occurs when the single operation state is set is used as the single operation detection condition. As shown in FIG. 14A, when the control by the reactive power compensator 100 ′ is stopped, the frequency deviation is 0.4 [Hz] after about 2 seconds from the occurrence of the independent operation due to the opening of the circuit breaker CB. The above-mentioned conditions are used, and the isolated operation state is detected on this condition.
However, as shown in FIG. 14B, when the control by the reactive power compensator 100 ′ is performed by the conventional method, the distributed power is distributed by the reactive power output by the reactive power compensator 100 ′ in the single operation state. The reactive power output from the power source 200 is canceled out, and as a result, the frequency deviation remains almost zero, so that the isolated operation state cannot be detected.

Note that a reactive power compensator described in Patent Document 2 is known as a conventional technique for preventing the isolated operation detection function of a distributed power source from being disturbed by the operation of the reactive power compensator.
FIG. 15 is a block diagram of this prior art. In FIG. 15, when the isolated operation state of the distributed power source is suspected, the isolated operation phenomenon determination signal S (= 1) is generated, and this determination signal S is input to the dead band width adjustment unit 410 in the reactive power command calculation unit 400. Then, the dead band width (the width of the voltage deviation between the voltage command value at the connection end and the voltage measurement value) is switched from D to D ′ (D <D ′).
The operation of the reactive power compensator is suppressed by switching the dead band on the input side of the proportional-plus-integral controller 420 to a wider D ′ by using the adjustment signal output from the dead band adjustment unit 410 described above. This prevents interference with the active islanding detection function.

JP-A-6-98469 (paragraphs [0027] to [0036], FIG. 1 and the like) JP-A-2017-147875 (paragraphs [0130] to [0152], FIGS. 17 to 19 and the like)

“Rules for Grid Connection (JEAC9701-2016)”, General Association of NEC Corporation Grid Linkage Expert Group, P.54-73, P.149-169, 2016

In the prior art described in Patent Document 2, the dead band width of the voltage deviation is switched discretely between the normal interconnection operation and the single operation of the distributed power source, and the dead band width cannot be continuously adjusted. There was a problem. In addition, when a single operation state is erroneously detected due to a disturbance in the system that accompanies frequency fluctuations during normal interconnection operation, the dead band width is frequently switched, or the dead band width is fixed to a wide D 'for a certain period of time and is invalid. Since a state in which power is not injected occurs, there is a problem that the voltage control performance during normal interconnection operation is significantly deteriorated.
Further, as a means for generating the isolated operation phenomenon determination signal S, a determination circuit for determining the isolated operation state based on the frequency detection value of the system voltage is necessary, and there is a problem that the circuit configuration and the control program become complicated. .

  Accordingly, the problem to be solved by the present invention is that the dead band width of the voltage deviation is continuously adjusted based on the period deviation and frequency deviation of the system voltage, and the reactive power compensation is performed according to the voltage deviation having the dead band. It is an object of the present invention to provide a reactive power compensator, a control program thereof, and a reactive power compensation system that do not impair the active islanding detection function of the present invention.

In order to solve the above problem, a reactive power compensator according to claim 1 is a reactive power compensator that injects reactive power into an electric power system and controls a voltage of the electric power system by operation of a power converter, In a reactive power compensator linked to the power system together with a distributed power source having a function of detecting reactive power by injecting reactive power into the power system,
A first means for calculating the period or frequency of the system voltage;
Second means for detecting a periodic deviation or a frequency deviation of a certain period using the output of the first means;
A third means capable of arbitrarily setting a dead band width according to the period deviation or the frequency deviation;
Fourth means for calculating a voltage deviation between the system voltage and a target voltage according to the dead band width set by the third means;
Fifth means for generating a reactive power command based on the voltage deviation;
A sixth means for generating a voltage command from the reactive power command and controlling the power converter according to the voltage command;
It is provided with.

A reactive power compensator according to claim 2 is a reactive power compensator for injecting reactive power into an electric power system and controlling a voltage of the electric power system by operation of a power converter, wherein the reactive power is supplied to the electric power system. In the reactive power compensator linked to the power system together with a distributed power source having a function of injecting and detecting a single operation state,
A first means for calculating the period or frequency of the system voltage;
Second means for detecting a periodic deviation or a frequency deviation of a certain period using the output of the first means;
A third means capable of arbitrarily setting at least one type of dead band for proportional control, integral control, and differential control according to the period deviation or frequency deviation;
A fourth means for calculating a voltage deviation between the system voltage and the target voltage in accordance with the dead band set by the third means;
Fifth means for generating a reactive power command based on the voltage deviation;
A sixth means for generating a voltage command from the reactive power command and controlling the power converter according to the voltage command;
It is provided with.

  The reactive power compensator according to claim 3 is the reactive power compensator according to claim 1 or 2, wherein the third means includes the periodic deviation or frequency deviation within a certain range of the periodic deviation or frequency deviation. It has a characteristic that the dead zone width increases as the value of becomes larger.

  The reactive power compensator according to a fourth aspect is the reactive power compensator according to any one of the first to third aspects, wherein the third means includes the period deviation or the frequency deviation within a certain range. The dead band width has a characteristic of changing linearly.

  A control program for a reactive power compensator according to claim 5 is a program installed in a computer system, wherein the first to sixth in the reactive power compensator according to any one of claims 1 to 4. The means is made to function.

  A reactive power compensation system according to a sixth aspect includes the reactive power compensation device according to any one of the first to fourth aspects, and the distributed power source having an isolated operation detection function based on a reactive power fluctuation method. It is characterized by that.

  A reactive power compensation system according to a seventh aspect includes the reactive power compensation device according to any one of the first to fourth aspects, and the distributed power source having an isolated operation detection function based on a reactive power compensation method. It is characterized by that.

ADVANTAGE OF THE INVENTION According to this invention, the reactive power compensation apparatus which does not interfere with the active independent operation detection function of the distributed power supply connected to the electric power system can be provided, This can further contribute to the prevention of accidents.
Further, the above-described non-interference function with respect to the distributed power supply can be realized by making the dead band of the voltage deviation variable, and it is not necessary to determine that the distributed power supply has shifted to the single operation state. The circuit configuration and control program can be simplified as compared with the prior art described in 1).

It is a block diagram of the reactive power compensation apparatus which shows embodiment of this invention. It is a block diagram which shows one Example of the independent driving | operation non-interference control part in FIG. It is explanatory drawing of the calculation principle of the period or frequency in the independent driving | operation non-interference control part of FIG. It is a block diagram of the period deviation detection part in FIG. It is operation | movement explanatory drawing of the dead zone width setting part in FIG. It is operation | movement explanatory drawing of the voltage deviation calculating part in FIG. It is a flowchart which shows the whole operation | movement of embodiment of this invention. It is a wave form diagram which shows the simulation result for verifying the effect of this invention. It is a block diagram which shows the other Example of the independent driving | operation non-interference control part in FIG. 1, and a voltage control part. It is operation | movement explanatory drawing of the dead zone width setting part in FIG. It is a block diagram of the conventional reactive power compensation apparatus. It is operation | movement explanatory drawing of the reactive power compensator linked to a commercial power system. It is a block diagram of an electric power system including a distributed power source and a reactive power compensator. It is an operation | movement waveform diagram at the time of employ | adopting a reactive power fluctuation system as an active isolated operation detection system. It is a block diagram of the reactive power compensation apparatus described in patent document 2.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a reactive power compensator 100 according to this embodiment, and the configuration of an AC controller 100A therein is different from the AC controller 100A ′ in the reactive power compensator 100 ′ shown in FIG. doing. In the following description, the AC control unit 100A will be described with a focus on differences from the AC control unit 100A ′, and other parts will not be described in detail in order to avoid duplication.

The AC control unit 100A in FIG. 1 includes an effective value calculation unit 120 that calculates the effective value V _r of the system voltage v _r . In addition, a deviation ΔV _r between the effective value V _r and the target voltage 130 is input, and a single unit that calculates ΔV _r ′ from the voltage deviation ΔV _r according to the dead band width that changes according to the cycle or frequency of the system voltage v _r. A driving non-interference control unit 110 is provided.
Note that the system in place of the effective value calculating unit 120 described above, to determine the deviation may be provided an amplitude calculation unit for calculating an amplitude value of similarly system voltage v _r and 11, short target voltage 130 it may be a means for converting the voltage v _r in the DC volume.

Next, FIG. 2 is a block diagram showing an embodiment of the isolated operation non-interference control unit 110.
2, (the first unit in the claims) period calculating section 111 calculates the period T (the reciprocal of the frequency f) of the system voltage v _r. The period T, as shown in FIG. 3, can be calculated from the time interval of the zero-crossing point of the system voltage v _r. In FIG. 3, the lowercase letter t indicates the time, and the uppercase letter T indicates the period.

Returning to FIG. 2, the period deviation detecting unit (second means in claims) 112 detects a period deviation ΔT for a certain period. For example, as shown in FIG. 4, the period deviation ΔT is obtained by subtracting the difference between the current period obtained by the moving average calculating unit 112a and the period of the past several cycles obtained through the moving average calculating unit 112b and the queue 112c. It is obtained by inputting to the device 112d.
Next, the dead band width setting unit (third means in the claims) 113 calculates the dead band width W according to the period deviation ΔT. For example, as shown in FIG. 5, a fixed range of the period deviation ΔT. The linear characteristic is such that the dead zone width W increases as the period deviation ΔT increases. In FIG. 5, W _DL is a lower limit value of the dead zone width W, and W _UL is an upper limit value.

FIG. 6 is an operation explanatory diagram of the voltage deviation calculation unit 114 (fourth means in the claims) in FIG. The voltage deviation calculation unit 114 calculates a voltage deviation ΔV _r ′ based on the voltage deviation ΔV _r and the dead band width W input from the subtractor 101 in FIG. 1, and the voltage control unit in FIG. To the fifth means) 140 in FIG. As described above, since the dead band width W changes according to the period deviation ΔT, in this embodiment, the voltage deviation ΔV _r ′ is calculated while continuously changing the dead band width W in real time according to the period deviation ΔT. be able to.
As is well known, since the cycle is the reciprocal of the frequency, a frequency calculator and a frequency deviation detector may be used instead of the cycle calculator 111 and the cycle deviation detector 112 of FIG.

Next, the overall operation of the reactive power compensator 100 according to the present embodiment will be described with reference to the flowchart of FIG.
First, to start the operation of the reactive power compensator 100 (step S1), and detects the system voltage _{v r} at the connection end of the power system 1 (step S2).
Next, the effective value calculator 120 calculates the effective value V _r of the system voltage v _r (step S3), and obtains a deviation ΔV _r from the target voltage 130 (step S4). In step S3, it may calculate the amplitude value instead of the effective value V _r as described above.

Further, by the operation of the single operation decoupling control unit 110 described with reference to FIG. 2, with obtaining the cycle T or the frequency f from the system voltage v _r, determine the cycle deviation ΔT or frequency deviation Δf based on these, the dead zone width setting The unit 113 calculates the dead zone width W. Further, by the operation of the voltage deviation calculation unit 114, the voltage deviation ΔV _r ′ is calculated based on ΔV _r and the dead zone width W (step S5).

Thereafter, the voltage control unit 140 in FIG. 1 _{calculates the} reactive current command I _qref (the reactive power command is synonymous with the reactive current command as described in claim 1) so that the voltage deviation ΔV _r ′ becomes zero. And output (step S6).
Based on the reactive current command I _qref , the coordinate conversion unit 160, the current control unit 180, the transformer voltage compensation unit 170, the adders 103 and 104, etc. operate to generate the voltage command V ^*, as in FIG. By applying this voltage command V ^* to the PWM circuit 190 to control the power converter INV, the reactive power compensator 100 injects reactive power into the power system 1 and controls the voltage at the connection end to the target voltage 130 ( Step S7). The portion from the coordinate conversion unit 160 to the PWM circuit 190 constitutes sixth means in the claims.
If the operation end command is input to the reactive power compensator 100, the process ends. If the operation continues, the process returns to step S2 and the above process is repeated until the operation end command is input (step S8).

Here, the reactive power compensator 100 according to the present embodiment is connected to the power system 1 together with the distributed power source 200 as shown in FIG. 13, and the distributed power source 200 is connected to the reactive power fluctuation method or reactive power compensation. Assume that the system has a single operation detection function.
In this case, the distributed when power supply 200 transitions to islanding state, the independent operation detecting function system voltage v fluctuation and thus the period of the periodic and frequency of _r deviation ΔT or frequency deviation Δf becomes large working such as reactive power fluctuation system, The dead band width W increases and the period during which the voltage deviation ΔV _r ′ becomes zero becomes longer. The reactive current command I _qref is not generated during the period in which the voltage deviation ΔV _r ′ is zero, and reactive power is not injected from the reactive power compensator 100 to the power system 1.
Therefore, the reactive power output from the distributed power source 200 is not canceled out, and the isolated operation detecting function is not likely to be disturbed by the reactive power compensator 100.

In this embodiment, the dead zone width setting section 113, it is possible to vary the dead zone width W in accordance with the cycle deviation ΔT or frequency deviation Δf of the system voltage v _r. That is, instead of determining whether or not the distributed power source 200 has shifted to the single operation state and switching the dead band width W discretely, the characteristic of the dead band width setting unit 113 is arbitrarily set and the reactive power compensator 100 is set. It is possible to control the operation or non-operation. Therefore, as described in Patent Document 2, in order to control the operation of the reactive power compensator 100, there is no need to provide a determination circuit or the like that determines that the distributed power source 200 has shifted to the single operation state. Therefore, the problem of erroneous detection does not occur when determining the isolated operation state, and voltage control performance during normal interconnection operation can be ensured.
If the linear characteristic is set as the characteristic of the dead band setting unit 113 in a certain range of the period deviation ΔT or the frequency deviation Δf as shown in FIG. 5, the reactive power compensator using the dead band W that continuously changes. 100 operations can be controlled.

  Next, FIG. 8 shows a simulation result for verifying the effect of the present invention. FIG. 8A is a waveform diagram during the control operation of the reactive power compensator according to the prior art, and FIG. 8B is a waveform diagram during the control operation of the reactive power compensator according to the present invention.

In the prior art of FIG. 8A, even when the circuit breaker CB is opened due to a system fault or the like, and the distributed power source shifts to the single operation state, the distributed power source is operated by the operation of the reactive power compensator based on the reactive current command. Since the reactive power to be output is canceled, the distributed power source cannot detect the isolated operation state.
On the other hand, in the present invention shown in FIG. 8B, the dead band width W changes according to the frequency deviation after the circuit breaker CB is opened, and a slight reactive current command is generated to operate the reactive power compensator. However, the reactive power output from the distributed power source cannot be canceled out, so the single operation detection function of the distributed power source can detect the single-acting operation state when the frequency deviation exceeds a predetermined threshold. Yes.

Next, another embodiment of the isolated operation non-interference control unit and the voltage control unit will be described with reference to FIG.
9, the single operation in the non-interference control section 110A includes a period calculation unit 111 which is likewise system voltage v _r and 2 are input, the period deviation detector 112 where the period T is input is the output provided It has been.

The period deviation ΔT detected by the period deviation detector 112 is input to three types of dead band width setting units (third means in claims) 113p, 113i, 113d.
In these dead band width setting sections 113p, 113i, and 113d, dead band widths W _p , W _i , and W _d for proportional control, integral control, and differential control corresponding to the period deviation ΔT are set, respectively. FIG. 10 shows an example of the dead band widths W _p , W _i , and W _d , and as in FIG. 5, within a certain range of the period deviation (or frequency deviation), it increases as the period deviation increases or is linear. It has characteristics that change to _{Incidentally, W pUL, W iUL, W} dUL upper limit of the dead zone _{width, W pDL, W iDL, W} dDL is the lower limit of the dead zone width.

The dead band widths W _p , W _i , and W _d described above are the voltage deviation calculation units (fourth means in claims) 114p, 114i, and 114d provided for proportional control, integral control, and differential control, respectively. In addition to these inputs, the voltage deviation ΔV _r calculated by the subtractor 101 of FIG. 1 is inputted to these voltage deviation calculation units 114p, 114i, and 114d.
The voltage deviation calculation units 114p, 114i, and 114d calculate the voltage deviations ΔV _p ′, ΔV _i ′, and ΔV _d ′ from the voltage deviation ΔV _r according to the dead band widths W _p , W _i , and W _d respectively input thereto. These voltage deviations ΔV _p ′, ΔV _i ′, and ΔV _d ′ are respectively transferred to the proportional control unit 140p, the integration control unit 140i, and the differentiation control unit 140d in the voltage control unit 140A (the fifth means in the claims). Entered.

The proportional control unit 140p, the integration control unit 140i, and the differential control unit 140d perform an adjustment operation so that the voltage deviations ΔV _p ′, ΔV _i ′, and ΔV _d ′ input thereto are zero, and outputs thereof are adders. 141 is added to the reactive current command I _qref .
The reactive current command I _qref is input to the coordinate conversion unit 160 in FIG. 1, and thereafter, reactive power compensation is performed by the same operation as described above.

In the above configuration, for example, when the voltage control unit 140A performs PI (proportional integration) control, the reactive current command I _qref is obtained by adding the outputs of the proportional control unit 140p and the integration control unit 140i, and PID (proportional integration) When differential control is performed, the outputs of the proportional control unit 140p, the integration control unit 140i, and the differential control unit 140d are added to obtain the reactive current command I _qref . When P (proportional) control is performed, the output of only the proportional control unit 140p may be _used as it is as the reactive current command I _qref .
As described above, in the embodiment described in FIGS. 9 and 10, the dead band width can be continuously adjusted according to the type of control calculation in the voltage control unit 140A, and the reactive power compensation is performed according to the voltage deviation having these dead bands. Do. The overall operation of the reactive power compensator is as shown in the flowchart of FIG.

As described above, according to the embodiment of the present invention, it is possible to provide the reactive power compensator 100 that does not impair the active islanding detection function of the distributed power source 200.
Note that the function of the AC control unit 100A shown in FIG. 1, that is, the series of control operations shown in FIG. 7, can be realized by hardware of a computer system and a control program installed in the hardware.

1: Power system 100: Reactive power compensator (SVC)
100A: AC control unit 101, 102: Subtractor 103, 104: Adder 110, 110A: Isolated operation non-interference control unit 111: Period calculation unit 112: Period deviation detection unit 112a, 112b: Moving average calculation unit 112c: Queue 112d: Subtractors 113, 113p, 113i, 113d: Dead band width setting unit 114, 114p, 114i, 114d: Voltage deviation calculation unit 120: Effective value calculation unit 130: Target voltage 140, 140A: Voltage control unit (AVR)
140p: Proportional control unit 140i: Integration control unit 140d: Differential control unit 141: Adder 150: Three-phase PLL circuit 160: Coordinate conversion unit 170: Transformer voltage compensation unit 180: Current control unit (ACR)
190: PWM circuit 200: Distributed power supply 300: Load INV: Power converter CT: Current detector CB: Circuit breaker Tr: Transformer VT: Voltage detector

Claims (7)

A reactive power compensator that injects reactive power into a power system and controls the voltage of the power system by the operation of a power converter, and has a function of injecting reactive power into the power system and detecting an isolated operation state. In the reactive power compensator linked to the power system together with the distributed power source provided,
A first means for calculating the period or frequency of the system voltage;
Second means for detecting a periodic deviation or a frequency deviation of a certain period using the output of the first means;
A third means capable of arbitrarily setting a dead band width according to the period deviation or the frequency deviation;
Fourth means for calculating a voltage deviation between the system voltage and a target voltage according to the dead band width set by the third means;
Fifth means for generating a reactive power command based on the voltage deviation;
A sixth means for generating a voltage command from the reactive power command and controlling the power converter according to the voltage command;
A reactive power compensator characterized by comprising: A reactive power compensator that injects reactive power into a power system and controls the voltage of the power system by the operation of a power converter, and has a function of injecting reactive power into the power system and detecting an isolated operation state. In the reactive power compensator linked to the power system together with the distributed power source provided,
A first means for calculating the period or frequency of the system voltage;
Second means for detecting a periodic deviation or a frequency deviation of a certain period using the output of the first means;
A third means capable of arbitrarily setting at least one type of dead band for proportional control, integral control, and differential control according to the period deviation or frequency deviation;
A fourth means for calculating a voltage deviation between the system voltage and the target voltage in accordance with the dead band set by the third means;
Fifth means for generating a reactive power command based on the voltage deviation;
A sixth means for generating a voltage command from the reactive power command and controlling the power converter according to the voltage command;
A reactive power compensator characterized by comprising: In the reactive power compensator according to claim 1 or 2,
The reactive power compensator according to claim 3, wherein the third means has a characteristic that the dead band width increases as the period deviation or frequency deviation increases within a certain range of the period deviation or frequency deviation. In the reactive power compensator according to any one of claims 1 to 3,
The third means has a characteristic that the dead band width changes linearly within a certain range of the period deviation or the frequency deviation.   A program mounted on a computer system, wherein the first to sixth means in the reactive power compensator according to any one of claims 1 to 4 are caused to function. Control program.   A reactive power compensation system comprising: the reactive power compensator according to any one of claims 1 to 4; and the distributed power source having an isolated operation detection function based on a reactive power fluctuation method.   A reactive power compensation system comprising: the reactive power compensation device according to any one of claims 1 to 4; and the distributed power source having an isolated operation detection function based on a reactive power compensation method.

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