JP2019075838A - Dispersion type power source and controller of the same - Google Patents

Abstract

To provide a dispersion type power source and a controller of the same which suppress quickly voltage fluctuation of a linkage point due to a reactive power output of a power converter and improve a generation efficiency.SOLUTION: In a dispersion type power source 150 having a DC power supply source 130, a power converter 120, and a controller 100, the controller 100 comprises an averaging processing unit 101 and a subtractor 103 which detect a voltage fluctuation amount ΔV of a linkage point, the averaging processing unit 101 and a sample-and-hold unit 102 which generate a voltage target value from a linkage point voltage, a subtractor 107, a voltage controller 109 and the like which generate a reactive power command Qfrom deviation ΔVbetween the voltage target value and a current linkage point voltage, an absolute value arithmetic unit 104, a comparator 106 and a convergence determination unit 108 which determine convergence of the voltage fluctuation by the voltage fluctuation amount ΔV, and the sample-and-hold unit 102, a progressive reduction controller 114, a changeover unit 115 and the like which output the gradually reduced reactive power command Qwhen the convergence determination unit 108 determines the convergence of the voltage fluctuation of the linkage point.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technology for suppressing voltage fluctuation at a connection point with an electric power system of a distributed power supply including a solar power generation system, a wind power generation system, and the like.

Distributed power sources such as a solar power generation system and a wind power generation system are usually interconnected to a power system via a power conditioner.
Here, it is known that the active power output from the distributed power source fluctuates depending on weather conditions etc., and the fluctuation of the active power fluctuates the voltage at the connection point with the power system, so the power system is stabilized. Cause inhibition.

As a prior art for suppressing the voltage fluctuation | variation in such a connection point, what was described in patent document 1 and patent document 2 is known, for example.
First, in Patent Document 1, a fluctuation component of a predetermined size or more is extracted from fluctuation components of the system voltage, and the fluctuation component is suppressed within a predetermined range to reduce reactive power (or reactive current, hereinafter the same) There is described a reactive power compensation device that calculates a control amount so as to match, and controls reactive power according to the control amount.

FIG. 11 is a control block diagram of the reactive power compensation device described in Patent Document 1. As shown in FIG.
In FIG. 11, reference numeral 501 denotes a low pass filter to which the connection point voltage V _r is input, 502 denotes a variable limiter for limiting the output voltage V ₀ of the low pass filter 501 by upper and lower limit values, and 503 denotes an output voltage V ₁ of the variable limiter 502. subtractor for calculating a voltage variation [Delta] V from the interconnection node voltage V _r, 504 is tolerance extracts voltage variation [Delta] V of magnitude greater than the (dead zone), the variation extracting section for outputting a signal [Delta] V _1, 505 Is a subtractor for obtaining the deviation between the reactive power measurement value and the setting value, 506 is an arithmetic circuit which outputs the signal ΔV ₂ by multiplying the output of the subtractor 505 by a predetermined gain, and 507 is the deviation ΔV of the signals ΔV ₁ and ΔV ₂ subtractor for obtaining the _F, 508 in the reactive power command _{Q ref} (specifically so that the deviation [Delta] V _F becomes zero, the phase control angle of the thyristor controlled reactor, corresponding to the command _{Q ref} PI to generate a decree) (which is a voltage control circuit such as a proportional integral) control.

On the other hand, Patent Document 2 calculates the voltage fluctuation amount, the active power and the interconnection point power factor at the interconnection point of the distributed power source and the electric power system, and approximates the relationship between the interconnection point active power and the voltage fluctuation amount. Calculate the slope of the linear function, add the power factor fluctuation amount set according to the interconnection point power factor and the increase or decrease of the inclination to the interconnection point power factor, and calculate the power factor command to make the inclination almost zero A controller of a distributed power supply is described which operates the power converter according to the power factor command.
In this prior art, the voltage fluctuation at the interconnection point is suppressed by controlling the reactive power output of the power converter constituting the distributed power supply without using the reactive power compensation device as shown in FIG. .

JP 2008-165499 A (paragraphs [0037] to [0042], FIG. 1, FIG. 2 etc.) Patent No. 5979404 (Paragraphs [0027] to [0041], FIG. 4 to FIG. 6, etc.)

  When the voltage fluctuation amount at the interconnection point is large, it is desirable to perform sufficient fluctuation suppression control using reactive power output by the power converter in the distributed power supply as described in Patent Document 2. On the other hand, when the voltage fluctuation amount at the interconnection point is within the allowable range, it is required to control the power converter so as not to output reactive power as much as possible from the viewpoint of preventing a decrease in power generation efficiency.

  In Patent Document 1, a method is adopted in which the reactive power is returned to a set value (for example, zero) when the voltage fluctuation amount is within the allowable range. However, according to this, as described in paragraph [0040] of Patent Document 1, the voltage fluctuation may not be sufficiently suppressed.

For example, FIG. 12 (a), the case where the system voltage as shown in (b) V and the interconnection point voltage _{V r} is decreased from the time _{T 1,} the low-pass filter 501 (FIG removing high frequency components from the interconnection point voltage _{V r} When the time constant (see 11) is short, the voltage fluctuation amount ΔV returns to zero as shown by the solid line in FIG. 12C, although the grid voltage V is decreasing. As a result, the reactive power command _Qref shown in FIG. 12D is controlled to zero, and the voltage fluctuation (voltage drop) can not be sufficiently suppressed.

  To solve the above problem, if the time constant of the low pass filter 501 is set long as shown by the broken line in FIG. 12C, the output of the reactive power compensation device is maintained even when the system voltage V drops. It becomes possible to control fluctuation. However, in this case, there has been a problem that the time during which the voltage fluctuation amount ΔV deviates from the allowable range (voltage fluctuation threshold) becomes long.

  Therefore, the problem to be solved by the present invention is to provide a distributed power supply capable of rapidly suppressing voltage fluctuation at a connection point by reactive power output from a power converter, and capable of improving power generation efficiency, and a control device therefor. It is in.

In order to solve the above-mentioned subject, invention concerning claim 1 is,
A DC power supply source,
A power converter connected between the DC power supply source and a power system;
By controlling the power converter, DC power of the DC power supply source is converted into AC power and supplied to the power system, and reactive power included in the AC power is controlled to control the power converter A controller capable of controlling a voltage at a connection point between the power system and the power system;
Distributed power supply with
The controller
A means for detecting the amount of voltage fluctuation at the connection point;
A means for generating a voltage target value of the interconnection point based on the voltage of the interconnection point;
Command generation means for generating a reactive power command for the power converter based on the deviation between the voltage target value and the current interconnection point voltage;
Convergence determination means for determining convergence of the voltage fluctuation based on the voltage fluctuation amount;
A gradual reduction control means for gradually reducing and outputting the reactive power command when the convergence determination means determines that the voltage fluctuation at the interconnection point has converged;
It is characterized by having.

  According to a second aspect of the present invention, in the dispersed power source according to the first aspect, the voltage target value is a value obtained by sampling and holding a moving average value of the interconnection point voltage when the voltage fluctuation amount exceeds a threshold. It is characterized by

  The invention according to claim 3 is the distributed power supply according to claim 1, wherein the voltage target value is a value obtained by sampling and holding a long period component of the interconnection point voltage when the voltage fluctuation amount exceeds a threshold. It is characterized by

  The invention according to claim 4 is the dispersed power source according to any one of claims 1 to 3, wherein the convergence determination means converges the voltage fluctuation when the voltage fluctuation amount is equal to or less than a threshold for a predetermined period. It is characterized by judging.

  The invention according to claim 5 is the distributed power source according to claim 4, wherein the first reactive power command generated by the command generation unit is the electric power until the convergence determination unit determines the convergence of the voltage fluctuation. The converter is characterized in that after the convergence judgment means judges convergence of the voltage fluctuation, the second reactive power command gradually reduced by the gradual reduction control means is supplied to the power converter.

  The invention according to claim 6 is the distributed power supply according to any one of claims 1 to 5, wherein the gradual reduction control means performs the voltage fluctuation amount on the basis of the current reactive power command sampled and held. The reactive power command is gradually reduced while maintaining the threshold value or less.

  The invention according to claim 7 is the distributed power supply according to claim 5, wherein the convergence determination unit does not determine the convergence of the voltage fluctuation while the second reactive power command is being gradually decreased by the gradual reduction control unit. The command generating means generates the first reactive power command with the current reactive power command sampled and held as an initial value.

The invention according to claim 8 is
A controller of a distributed power supply, comprising: a DC power supply source; and a power converter connected between the DC power supply source and a power system,
By controlling the power converter, DC power of the DC power supply source is converted into AC power and supplied to the power system, and reactive power included in the AC power is controlled to control the power converter A controller capable of controlling a voltage at a connection point between the power system and the power system,
A means for detecting the amount of voltage fluctuation at the connection point;
A means for generating a voltage target value of the interconnection point based on the voltage of the interconnection point;
Command generation means for generating a reactive power command for the power converter based on the deviation between the voltage target value and the current interconnection point voltage;
Convergence determination means for determining convergence of the voltage fluctuation based on the voltage fluctuation amount;
A gradual reduction control means for gradually reducing and outputting the reactive power command when the convergence determination means determines that the voltage fluctuation at the interconnection point has converged;
It is characterized by having.

According to the present invention, it is possible to instantaneously reduce the voltage deviation at the connection point with the power system.
In addition, after the voltage fluctuation at the interconnection point converges, the reactive power output by the power converter can be controlled to zero without giving a fluctuation above the threshold to the grid voltage, so the power generation efficiency of the distributed power supply can be improved. be able to.

FIG. 1 is an overall configuration diagram of a power system to which an embodiment of the present invention is applied. It is a block diagram of a control device concerning an embodiment of the present invention. It is operation | movement explanatory drawing of the gradual reduction control part in FIG. It is a flowchart which shows operation | movement of the control apparatus which concerns on embodiment of this invention. It is a block diagram which shows the principal part of the invention which concerns on Claim 2, 3. It is a block diagram which shows the principal part of the invention which concerns on Claim 4. FIG. It is a block diagram which shows the principal part of the invention which concerns on Claim 5. FIG. It is a block diagram which shows the principal part of the invention which concerns on Claim 6. FIG. It is a block diagram which shows the principal part of the invention which concerns on Claim 7. FIG. It is a figure for demonstrating the effect of embodiment of this invention. It is a control block diagram of the prior art based on patent document 1. FIG. It is a figure for demonstrating the problem of the prior art which concerns on patent document 1. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, FIG. 1 is an overall configuration diagram of a power system to which an embodiment of the present invention is applied. In FIG. 1, a load 400 is connected to an AC power system 200 such as a commercial power source via an interconnection 300. Here, the load 400 has a function of exchanging AC power with the power system 200, and includes a generator in a broad sense.

Reference numeral 150 denotes a distributed power source such as a solar power generation system or a wind power generation system. The distributed power supply 150 is connected to a connection point on the connection line 300 via the voltage detector VT1, and the control device 100, the power converter 120, a DC power supply source 130 such as a solar cell panel, and voltage detection It has the vessel VT2.
Power converter 120 is formed of an inverter or the like that constitutes a so-called power conditioner system (PCS). The power converter 120 converts the direct current power of the direct current power supply source 130 into alternating current power by the control device 100 controlling on / off of the semiconductor switching element, and supplies the alternating current power to the power system 200 via the interconnection point.

Further, the control unit 100, based on the interconnection point voltage V _r detected by the voltage detector VT1, given the reactive power command Q _ref generated by the operation described below to the power converter 120, power converter 120 is the command Output reactive power according to Q _ref . Although control device 100 also has a protective function to stop power converter 120 when direct-current voltage E _dc detected by voltage detector VT 2 exceeds a predetermined threshold, etc., these functions are the same as those of the present invention. The description is omitted here because there is no direct relationship.

Next, the configuration and operation of the control device 100 will be described.
FIG. 2 is a block diagram showing the configuration of the control device 100. As shown in FIG. In FIG. 2, the interconnection point voltage V _r is converted into a voltage V ₁ by an averaging processing unit 101 such as a low pass filter that performs moving average processing, first-order delay calculation (detection of long period components), etc. The signal is input to the hold unit 102 and the subtractor 103.
The subtracter 103 calculates the voltage variation [Delta] V from the voltage V ₁ and the interconnection point voltage V _r, the voltage fluctuation [Delta] V is the absolute value is input to the absolute value calculation unit 104 | [Delta] V | is calculated.

The absolute value | ΔV | is input to the comparison unit 106 together with the threshold (eg, 0.02 [p.u.] (2 [%]) 105, and the comparison unit 106 determines that | ΔV | Output "1".
The output signal of the comparator 106 is input to the first sample-and-hold unit 102, the sample-and-hold unit 102, the voltage target value V _h while the output signal is a period of time holds the input signal V ₁ when "1" and outputs as said output signal is outputted as it is as the voltage target value V _h of the input signal V ₁ was in a period of "0". The voltage target value V _h is input to the subtractor 107, and the deviation ΔV _{h from} the current connection point voltage V _r is calculated.

  The output signal of the comparison unit 106 is also input to the convergence determination unit 108. In this convergence determination unit 10, for example, | ΔV | is 0.02 [p. u. It is determined that the voltage fluctuation at the interconnection point has converged when the following condition continues for 10 seconds, and the output signal (convergence determination signal) is inverted from "0" to "1".

The convergence determination signal described above and the deviation ΔV _h output from the subtractor 107 are input to a voltage control unit 109 including a PI (proportional integration) regulator. The voltage control unit 109 corresponds to a command generation unit in the claims.
Voltage control unit 109 takes in the output of multiplier 112 described later as an initial value of the integrator, resets the integrator when the convergence determination signal is “1”, and operates so that deviation ΔV _h becomes zero. The first reactive power command Q _refA is output.

The convergence determination signal is also input to the code inverting unit 110, the third sample and hold unit 113, and the switching unit 115.
The output of the code inverting unit 110 is input to the second sample hold unit 111 and the multiplier 112 to which the reactive power command Q _ref which is the output value of the control device 100 is input. The second sample and hold unit 111, the output signal of the sign inversion unit 110 by a predetermined period and holds the reactive power command Q _ref when "1" is output, the reactive power command Q _ref is a voltage via the multiplier 112 The integrator initial value of the control unit 109 is obtained. Note that the integrator initial value is 0 during a period in which the output signal of the sign inverting unit 110 is “0”.

When the output signal of the convergence determination unit 108 is “1”, the third sample and hold unit 113 holds the reactive power command Q _ref which is the output value of the control device 100 for a certain period, and gradually decreases the command as the command Q _refh. Output to 114.
Here, FIG. 3 shows the operation of the gradual reduction control unit 114, and outputs a second reactive power command Q _refB that gradually reduces Q _refh to 0 as time passes.

The second reactive power command _{Q refB} output from the first reactive power command _{Q refA} a gradual reduction control unit 114 which is output from the voltage control unit 109 are given to the input side of the switching portion 115. The switching unit 115 selects the first reactive power command Q _refA when the convergence determination signal is “0”, and selects the second reactive power command Q _refB when the convergence determination signal is “1”. One of them is output as a reactive power command Q _ref . The reactive power command _Qref is sent to the power converter 120 of FIG. 1, and predetermined reactive power is supplied to the interconnection point by the operation of the semiconductor switching element.

Next, the operation of the control device 100 described above will be described along the flowchart of FIG.
[START]
In the initial state of control, reactive power command Q _ref = 0, which is the output value of control device 100, the convergence determination signal is “1”, and switching unit 115 is “1” (second reactive power command Q _refB ) Control is started from
[Step S10]
This is an interrupt process at the time of stopping the control, and when the control by the control device 100 is continued, the process proceeds to step S11.

[Step S11]
The reactive power command Q _ref is gradually reduced by the operation of the gradual reduction control unit 114. In the initial state, Q _ref (Q _refB ) = 0 remains output.
[Step S12]
The interconnection point voltage V _r is detected.
[Step S13]
The averaging processor 101 calculates V ₁ , and the subtractor 103 calculates the voltage fluctuation amount ΔV from V ₁ and V _r .

[Step S14]
The absolute value | ΔV | of ΔV is calculated by the absolute value calculator 104, and the result is compared with the threshold 105 by the comparator 106. As described above, the threshold 105 is, for example, 0.02 [p. u. ] (2 [%]) is set.
Is 0.02 [p. u. If not, the comparison unit 106 outputs “0”, and the process returns to step S10. Therefore, the state of reactive power command Q _ref = 0 is maintained.
Further, | ΔV | is 0.02 [p. u. If the comparison result exceeds “1”, the comparison unit 106 outputs “1” and proceeds to the next step S15.

[Step S15]
When the comparison unit 106 outputs “1”, the first sample hold unit 102 holds V ₁ sampled at that moment, in other words, the interconnection point voltage V _r, and outputs the value as the voltage target value V _h Do.
[Step S16]
This is an interrupt process at the time of stopping the control, and when the control by the control device 100 is continued, the process proceeds to step S17.

[Step S17]
The deviation [Delta] V _h of the voltage target value _{V h} and the current interconnection point voltage _{V r} calculated by the subtractor 107, and inputs the deviation [Delta] V _h to the voltage control unit 109. The voltage control unit 109 performs an operation such that ΔV _h becomes zero by, for example, the operation of the PI regulator, and outputs a first reactive power command Q _refA .
On the other hand, when the input value (the output value of the comparison unit 106) changes from “0” to “1”, the convergence determination unit 108 instantly inverts the output value from “1” to “0”. Thus, the input of the switching section 115 is selected first reactive power command _{Q refA} for switching to the voltage control unit 109 side, the _{Q refA} is output to the power converter 120 as the reactive power command _{Q ref.}

[Step S18]
While monitoring the voltage V _r at the connection point, the control to make the deviation ΔV _h zero is continued, while the output of the reactive power command Q _ref (= the first reactive power command Q _refA ) is maintained.
[Step S19]
While continuing the operation of step S18, the voltage fluctuation amount ΔV is calculated from V ₁ and V _r .

[Step S20]
The absolute value | ΔV | of the voltage fluctuation amount ΔV has a threshold value of 0.02 [p. u. If it is determined that the voltage variation has converged by the convergence determination unit 108, the process returns to step S11 via step S10. As described above, in the convergence determination by the convergence determination unit 108, for example, | ΔV | is 0.02 [p. u. It is determined that the voltage fluctuation has converged when the following condition continues for 10 seconds, and the convergence determination signal is inverted from "0" to "1".
If it is determined that the voltage fluctuation has not converged, the process returns to step S16, and the control from step S17 onward (control to make the deviation ΔV _h zero until the stop of the control is instructed or the voltage fluctuation converges) Continue).

When it is determined in step S20 that the voltage fluctuation has converged, and the process proceeds to step S11 via step S10, the third sample-and-hold unit 113 in FIG. 2 _performs command Q _refh obtained by sampling and holding reactive power command Q _ref. The command Q _refh is output to the gradual reduction control unit 114. Further, since the input of the switching unit 115 is switched to the gradual decrease control unit 114 side by the convergence determination unit 108 outputting “1”, the second reactive power command Q _refB is an output value of the control device 100 (reactive power command Q It becomes _ref ).
The operation of the gradual decrease control unit 114 is, for example, | ΔV | u. ] While maintaining within, Q _refB is gradually _reduced from Q _refh to 0 as described above.

[END]
When a control stop command is generated by the automatic operation or the manual operation, this is determined in step S10 or S16, and the control is ended.

FIG. 10 is an operation explanatory view showing the effect of the present embodiment.
When the system voltage V shown in FIG. 10 (a) at time T ₁ is lowered, as shown in FIG. 10 (c), momentarily increases the voltage variation [Delta] V, the output is momentarily in the comparison unit 106 of FIG. 2 " It becomes "1" and returns to "0" immediately. The output "1" of the comparison unit 106, a first sample-and-hold unit 102 holds the voltages _{V 1} based on the interconnection point voltage _{V r} in FIG. 10 (b), and outputs a voltage target value _{V h.}

Time _{T 1} after the voltage control unit 109 of FIG. 2 as to match the interconnection point voltage _{V r} to the voltage target value _{V h,} and calculates a first reactive power command _{Q refA} shown in FIG. 10 (d) Output. Then, since the output of the convergence determination unit 108 is “0” from time T ₁ to time T ₂ after the convergence determination time (for example, 10 seconds), the reactive power command Q _refA described above is reactive power via the switching unit 115 It is output as the command Q _ref . As a result, work is reactive power compensation with the power converter 120 of FIG. 1, a decrease in interconnection node voltage V _r at time T ₁ through T _2, as shown in FIG. 10 (b) becomes a negligible value.

Time T _2, thereafter has elapsed the convergence determination period from time T _1, the convergence determination signal by the convergence determination portion 108 is "1". As a result, the second reactive power command Q _refB for gradually decreasing the sample hold value Q _refh by the third sample and hold unit 113 to 0 by the gradual decrease control unit 114 is selected, and this is selected via the switching unit 115 as the reactive power command Q _ref. It becomes.
By the power converter 120 performs reactive power compensation in accordance with this way gradually reduced to continue reactive power command Q _ref, interconnection node voltage V _r in FIG. 10 (b) time T _2, after, gradually lowered , it decreases also the output V ₁ of the averaging unit 101 in accordance with the interconnection point voltage V _r. For this reason, the voltage fluctuation amount ΔV in FIG. u. There is no risk of increasing beyond.

As described above, according to the present embodiment, the voltage fluctuation amount ΔV at the interconnection point can be instantaneously reduced to within the threshold, and after the voltage fluctuation converges, the reactive power output by the power converter 120 can be controlled to zero. Because of this, the power generation efficiency of the distributed power source can be improved.
Although the distributed power supply according to the present invention can be realized by providing the configuration described in claim 1, the effect becomes more remarkable if the configuration described in claims 2 to 7 is further provided. . Here, in FIG. 5, the portions according to claims 2 and 3 are surrounded by alternate long and short dashed lines, and in each of FIGS. 6 to 9, the portions according to claims 4 through 7 are enclosed by alternate long and short dashed lines. The configuration and operation of these parts are as described in detail above. Further, as described above, the control device according to claim 8 is realized by the configuration of FIG. 2, for example.

100: control device 101: averaging processing unit 102, 111, 113: sample and hold unit 103, 107: subtractor 104: absolute value calculation unit 105: threshold 106: comparison unit 108: convergence determination unit 109: voltage control unit 110: Code inversion unit 112: Multiplier 114: Gradual control unit 115: Switching unit 120: Power converter 130: DC power supply source 150: Distributed power supply 160: Interconnection transformer 200: AC power system 300: Interconnection line 400: Load (Including generator)
VT1, VT2: Voltage detector

Claims (8)

A DC power supply source,
A power converter connected between the DC power supply source and a power system;
By controlling the power converter, DC power of the DC power supply source is converted into AC power and supplied to the power system, and reactive power included in the AC power is controlled to control the power converter A controller capable of controlling a voltage at a connection point between the power system and the power system;
Distributed power supply with
The controller
A means for detecting the amount of voltage fluctuation at the connection point;
A means for generating a voltage target value of the interconnection point based on the voltage of the interconnection point;
Command generation means for generating a reactive power command for the power converter based on the deviation between the voltage target value and the current interconnection point voltage;
Convergence determination means for determining convergence of the voltage fluctuation based on the voltage fluctuation amount;
A gradual reduction control means for gradually reducing and outputting the reactive power command when the convergence determination means determines that the voltage fluctuation at the interconnection point has converged;
Distributed power supply characterized by having. In the distributed power supply according to claim 1,
The distributed power supply characterized in that the voltage target value is a value obtained by sampling and holding a moving average value of a voltage at a connection point when the voltage fluctuation amount exceeds a threshold. In the distributed power supply according to claim 1,
The distributed power supply according to claim 1, wherein the voltage target value is a value obtained by sampling and holding a long period component of a voltage at a connection point when the voltage fluctuation amount exceeds a threshold. In the distributed power supply according to any one of claims 1 to 3,
The distributed power supply characterized in that the convergence determining means determines the convergence of the voltage fluctuation when the voltage fluctuation amount is equal to or less than a threshold for a predetermined period. In the distributed power supply according to claim 4,
The first reactive power command generated by the command generation unit is provided to the power converter until the convergence judgment unit determines that the voltage fluctuation has converged.
A distributed power supply characterized in that the second reactive power command gradually reduced by the gradual reduction control means is given to the power converter after the convergence judgment means determines the convergence of the voltage fluctuation. In the distributed power supply according to any one of claims 1 to 5,
The distributed power supply characterized in that the gradual decrease control means gradually reduces the reactive power command while maintaining the voltage fluctuation amount below a threshold value based on the current reactive power command sampled and held. In the distributed power supply according to claim 5,
When the convergence determination means does not determine the convergence of the voltage fluctuation while the second reactive power command is being gradually reduced by the gradual reduction control means, the command generation means performs an initial value on the current reactive power command sampled and held. Generating a first reactive power command as a distributed power supply. A controller of a distributed power supply, comprising: a DC power supply source; and a power converter connected between the DC power supply source and a power system,
By controlling the power converter, DC power of the DC power supply source is converted into AC power and supplied to the power system, and reactive power included in the AC power is controlled to control the power converter A controller capable of controlling a voltage at a connection point between the power system and the power system,
A means for detecting the amount of voltage fluctuation at the connection point;
A means for generating a voltage target value of the interconnection point based on the voltage of the interconnection point;
Command generation means for generating a reactive power command for the power converter based on the deviation between the voltage target value and the current interconnection point voltage;
Convergence determination means for determining convergence of the voltage fluctuation based on the voltage fluctuation amount;
A gradual reduction control means for gradually reducing and outputting the reactive power command when the convergence determination means determines that the voltage fluctuation at the interconnection point has converged;
A controller of a distributed power supply, comprising:

Images