JP5469624B2 - Reactive power compensator - Google Patents

Description

  The present invention relates to a reactive power compensator that outputs reactive power to a power system to adjust a system voltage.

  In general, in an electric power system to which a load whose electric power fluctuates greatly is connected, the voltage of the electric power system fluctuates according to a current flowing through the load. There is a reactive power compensator as one of the devices installed to suppress such voltage electric drive. This reactive power compensator outputs the advanced reactive power to the power system when the system voltage is lowered, while the delayed reactive power is output to the power system when the system voltage is increased. It adjusts (for example, refer patent document 1). The reactive power compensator suppresses steady voltage fluctuation while always operating according to the difference between the system voltage and the set voltage.

JP 2001-268805 A

  By the way, when the reactive power compensator is operating in order to compensate for the steady reactive power due to the load, if more active power and reactive power are generated by another load, there is a margin in the output of the reactive power compensator. There was a risk that further active power and reactive power could not be compensated. Therefore, there has been a demand for a reactive power compensator that can cope with further fluctuations in active power and reactive power.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a reactive power compensator that can cope with further fluctuations in active power and reactive power.

Hereinafter, means for achieving the above-described object and its operation and effects will be described.
The invention according to claim 1 is a reactive power compensator using a constant power factor control system that outputs reactive power to the power system in order to stabilize the system voltage of the power system. A reactive power lower limit value is set, a reactive power setting range is set with the reactive power upper limit value as an upper limit and the reactive power lower limit value as a lower limit, and the output reactive power is within the reactive power setting range. The gist of this is to make changes.

  According to this configuration, the reactive power upper limit value and the reactive power lower limit value are set above and below the output reactive power, and the reactive power upper limit value is set as the upper limit and the reactive power lower limit value is set as the lower limit. The output reactive power is changed stepwise so that the reactive power is within the reactive power setting range. For this reason, since the output reactive power is set so as to be within the reactive power setting range, the reactive power can be output with a margin without being adjusted to one point of the set reactive power. Therefore, it is possible to suppress steady output of reactive power and cope with further fluctuations of active power and reactive power.

  The gist of the invention according to claim 2 is that, in the reactive power compensator according to claim 1, the average value of the output reactive power in a certain time is changed so as to approach the reactive power setting range.

  According to this configuration, the average value of the output reactive power for a predetermined time is changed so as to approach the reactive power setting range. For this reason, output reactive power can be suppressed and it can respond to the further fluctuation | variation of active power and reactive power.

  According to a third aspect of the present invention, in the reactive power compensator according to the first or second aspect of the present invention, an output margin amount for allowing a margin for the output reactive power is set, and the output reactive power is within the reactive power setting range. The gist of the invention is that the output reactive power is not changed when the output reactive power is outside, and the output reactive power is changed stepwise when the output reactive power is outside the reactive power setting range. .

  According to the configuration, the output reactive power is not changed when the reactive power is within the reactive power setting range, and when the reactive power is outside the reactive power setting range, the output reactive power is reduced by changing the output margin amount step by step. change. For this reason, it is possible to suppress the output of reactive power.

  According to a fourth aspect of the present invention, in the reactive power compensator according to any one of the first to third aspects of the present invention, an output tolerance amount for giving a margin to the output reactive power is set, and the output margin amount is set. An output tolerance amount upper limit value as an upper limit value and an output tolerance amount lower limit value as a lower limit value of the output tolerance amount are set, the output tolerance amount upper limit value is an upper limit, and the output tolerance amount lower limit value is a lower limit. Set the output tolerance amount setting area, and when the output tolerance amount is equal to or higher than the output tolerance amount upper limit value due to the change of the output reactive power, the output tolerance amount is set to the output tolerance amount upper limit value, The gist of the invention is that when the output tolerance amount is equal to or less than the output tolerance amount lower limit value, the output tolerance amount is set to the output tolerance amount lower limit value.

  According to this configuration, when the output margin amount is equal to or greater than the output tolerance amount upper limit value, the output tolerance amount is set to the output tolerance amount upper limit value, and when the output tolerance amount is equal to or less than the output tolerance amount lower limit value, the output is performed. Set the tolerance amount to the output tolerance amount lower limit value. For this reason, it is possible to suppress an excessive increase and decrease in the output margin amount due to fluctuations in the output reactive power. Therefore, it is possible to effectively use the region that can be output by the reactive power compensator according to the load fluctuation.

  The invention according to claim 5 is the reactive power compensator according to any one of claims 1 to 4, wherein the voltage upper limit value and the voltage lower limit value are set, the voltage upper limit value is set to the upper limit, and the voltage The gist is to set a voltage setting range having a lower limit as a lower limit, and to perform constant voltage control so that the system voltage is within the voltage setting range when the system voltage deviates from the voltage setting range.

  According to this configuration, a voltage upper limit value and a voltage lower limit value are set, and a voltage setting range with the voltage upper limit value as an upper limit and the voltage lower limit value as a lower limit is set so that the system voltage is within the voltage setting range. Performs constant voltage control. For this reason, it is possible to prevent the system voltage from fluctuating greatly.

  ADVANTAGE OF THE INVENTION According to this invention, the reactive power compensation apparatus can respond to the further fluctuation | variation of active power and reactive power.

The block diagram which shows schematic structure of a reactive power compensation apparatus. The flowchart which shows control of a reactive power compensation apparatus. The figure which shows operation | movement of a reactive power compensation apparatus. The figure which shows operation | movement of a reactive power compensation apparatus. The flowchart which shows control of a reactive power compensation apparatus. The figure which shows operation | movement of a reactive power compensation apparatus. The flowchart which shows control of a reactive power compensation apparatus. The figure which shows operation | movement of a reactive power compensation apparatus.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the reactive power compensator 10 is connected in parallel to the power system 1 via a switch 2 and a transformer 3. The reactive power compensator 10 is a device that adjusts a system voltage of the power system 1, for example, 6600 V, by supplying reactive power when voltage fluctuation occurs due to the load 4 or the like connected to the power system 1. The reactive power compensator 10 of the present embodiment includes an inverter 11 in a main circuit, and a connected reactor 12 is connected to the inverter 11. The interconnecting reactor 12 is connected to the transformer 3 and connected to the power system 1 via the switch 2. A capacitor 13 for establishing a potential is connected to the inverter 11. The switch 2 is provided with two current sensors CT for detecting the current of the power system 1 and a voltage sensor PT for detecting the voltage of the power system 1 (hereinafter referred to as system voltage). Further, the reactive power compensator 10 is provided with a control device 14. Two current sensors CT and a voltage sensor PT are connected to the control device 14. The reactive power compensator 10 adjusts the voltage of the power system 1 by continuously varying the output while adjusting the reactive power flowing through the interconnection reactor 12 by the voltage difference between the system voltage and the inverter output voltage. The reactive power compensator 10 of the present embodiment is an SVG (Static Var Generator) type device.

  The reactive power compensator 10 synchronizes the output voltage of the inverter 11 with the phase of the system voltage and changes the magnitude thereof, so that a forward current flows through the interconnection reactor 12 with a delay of 90 degrees from the system voltage. That is, when viewed from the electric power system 1, the reactive power compensator 10 operates as if a variable phase advance capacitor or a shunt reactor is connected. For example, when the voltage of the power system 1 decreases due to the fluctuation of the load 4, the voltage is raised by performing the same operation as that of the phase advance capacitor as viewed from the power system 1. Moreover, when the voltage of the electric power grid | system 1 rises, seeing the electric power grid | system 1, the operation | movement similar to a shunt reactor is performed and a voltage is lowered | hung.

  The reactive power compensator 10 performs “power factor constant control” for managing the power factor of the interconnection point at a constant level. The constant power factor control detects reactive power on the load side of the interconnection point and continuously generates reactive power so that the power factor on the power source side is constant. The reactive power compensator 10 suppresses voltage fluctuation by power factor constant control.

As shown in FIGS. 2 and 3, the reactive power compensator 10 performs control so that the power factor of the power system 1 is constant. Here, the reactive power compensator 10 performs output control of the reactive power Q _O to stabilize the output reactive power Q _O reactive power setting region within Q _H-L. That is, the reactive power compensator 10 sets the output tolerance amount Q _i that behaves as if there is a virtual load or a virtual power supply so that the output reactive power Q _O has a margin.

As shown in FIG. 2, first, the control device 14 of the reactive power compensator 10 performs power factor constant control so that the output reactive power Q _O becomes the output command value A (step S10). Here, the output command value A = − (load reactive power Q _r ) + (load active power P _r ) × tan θ− (output margin amount Q _i ). The output command value A is changed by changing the output margin amount Q _i .

Subsequently, the control device 14 determines whether or not the sampling time T _S has elapsed in order to measure the output reactive power Q _O for a certain time (step S11). Controller 14, when the sampling time _{T S} has not elapsed: (step S11 NO), waits until the elapsed. On the other hand, the control unit 14, if the sampling time _{T S} has elapsed (step S11: YES), the CPU changes the output command value A based on the average value Σ of the output reactive power _{Q O.} That is, the control unit 14 determines the mean value Σ of the output reactive power _{Q O} (step S12). The output is the average value sigma of the reactive power Q _O, a value of the integral value Q _sigma output reactive power Q _O divided by the sampling time T _S at the sampling time T _S. The sampling time T _S is equivalent to a predetermined time.

Subsequently, when the average value Σ of the output reactive power Q _O is larger than the reactive power upper limit value Q _{H of the} reactive power setting range Q _HL (Σ> Q _H ), the control device 14 outputs the output margin amount Q _i a change to the current output Hiroshi metric _{Q i} to a value obtained by adding the change width _{ΔQ i (Q i = Q i} + ΔQ i) ( step S13). In other words, the control device 14 determines that the output tolerance amount Q _i has shifted above the reactive power upper limit value Q _{H of the} reactive power setting range Q _HL and changes the current output tolerance amount Q _i . By increasing the width ΔQ _i , the output reactive power Q _O is reduced by the change width ΔQ _i, and a margin is provided for the reactive power output.

Further, when the average value Σ of the output reactive power Q _O is smaller than the reactive power lower limit value Q _{L of the} reactive power setting range Q _HL (Σ <Q _L ), the control device 14 outputs the output margin amount Q _i. the change to the current output Hiroshi metric _{Q i} minus the change width Delta] Q _i from _{(Q i = Q i -ΔQ i} ) ( step S14). That is, the control device 14 determines that the output tolerance amount Q _i is changing below the reactive power lower limit value Q _{L of the} reactive power setting range Q _HL and determines the current output tolerance amount Q _i . By reducing the change width ΔQ _i , the output reactive power Q _O is increased by the change width ΔQ _i, so that the reactive power output has a margin.

Further, when the average value Σ of the output reactive power Q _O is within the reactive power setting range Q _HL (Q _L ≤ Σ ≤ Q _H ), the control device 14 outputs the output reactive power Q _O as the current output. The tolerance amount Q _i remains unchanged (Q _i = Q _i ) (step S15).

  Next, an operation mode of the reactive power compensator 10 when the reactive power compensator 10 configured as described above is installed in the power system 1 will be described. As shown in FIG. 3, a case where reactive power is continuously generated in the power system 1 will be described.

First, the output tolerance amount Q _i of the reactive power compensator 10 is set to zero. In addition, load reactive power Q _r of the power system 1 is zero. Then, reactive power Q having a steep (+) delay is generated in the power system 1 in the eleventh sampling time T _S 11. At this time, the reactive power compensator 10 proceeds to the power system 1 and outputs (−) reactive power. In other words, the reactive power compensator 10 outputs the output reactive power Q _O opposite in magnitude to the load reactive power Q _r of the power system 1. Further, the average value Σ of the output reactive power Q _O falls within the reactive power setting range Q _HL (Q _L <Σ <Q _H ). Therefore, the reactive power compensator 10 sets the current output reactive power Q _O at the twelfth sampling time T _S 12.

Subsequently, the reactive power compensator 10 maintains the output reactive power Q _O at the same value as the eleventh sampling time T _S 11 in the twelfth sampling time T _S 12. Further, since the average value Σ of the output reactive power Q _O is lower than the reactive power lower limit value Q _L of the reactive power setting range Q _HL (Σ <Q _L ), the reactive power compensator 10 outputs the reactive power and a value greater than Q _O. Therefore, reactive power compensator 10, the _Q i -DerutaQ _i minus the reactive power variation range Delta] Q _i from the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} That is, the reactive power compensator 10 sets Q _O + ΔQ _i obtained by adding the change width ΔQ _i to the current output reactive power Q _O as the new output reactive power Q _O in the thirteenth sampling time T _S 13.

Subsequently, the reactive power compensator 10 sets the output reactive power Q _O to a value increased by the change width ΔQ _i from the twelfth sampling time T _S 12 in the thirteenth sampling time T _S 13. Further, since the average value Σ of the output reactive power Q _O is lower than the reactive power lower limit value Q _L of the reactive power setting range Q _HL (Σ <Q _L ), the reactive power compensator 10 outputs the reactive power and a value greater than Q _O. Therefore, reactive power compensator 10, the _Q i -DerutaQ _i minus the reactive power variation range Delta] Q _i from the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} That is, the reactive power compensator 10 sets Q _O + ΔQ _i obtained by adding the change width ΔQ _i to the current output reactive power Q _O as the new output reactive power Q _O at the fourteenth sampling time T _S 14.

Further, the reactive power compensator 10 sets the output reactive power Q _O to a value that is increased by the change width ΔQ _i from the thirteenth sampling time T _S 13 in the fourteenth sampling time T _S 14. Further, since the average value Σ of the output reactive power Q _O falls within the reactive power setting range Q _HL (Q _L <Σ <Q _H ), the reactive power compensator 10 changes the current output margin amount Q _i . do not do. Therefore, the reactive power compensator 10 sets the current output reactive power Q _O also in the fifteenth sampling time T _S 15. Thereafter, reactive power compensator 10, if the output reactive power _{Q O} the average value sigma reactive power setting region within _{Q H-L} and _{(Q L <Σ <Q H} ), set the current output reactive power _{Q O} To do.

Here, in a consumer, when a steep voltage fluctuation occurs, flicker or the like occurs, which is a problem. For this reason, it is important to suppress the steep voltage fluctuation corresponding to the steep voltage fluctuation. When the reactive power compensator 10 outputs reactive power to the power system 1 at the maximum output range, it becomes impossible to cope with steep voltage fluctuations. Therefore, the reactive power compensator 10 according to the present embodiment brings the output reactive power Q _O closer to the reactive power setting range Q _HL as described above, and immediately when the system voltage greatly fluctuates from the current value. Correspondingly, it becomes possible to output reactive power at the maximum of the output range, and it is possible to suppress steep voltage fluctuations.

Next, as shown in FIG. 4, a case where reactive power Q is generated in the power system 1 will be described. The reactive power compensator 10 has the output reactive power Q _O set to zero when the reactive power Q is set.

First, the output tolerance amount Q _i of the reactive power compensator 10 is set to −Q. In addition, a reactive power Q with a delay (+) is generated in the power system 1. At this time, the output reactive power Q _O of the reactive power compensator 10 is zero. Then, a value close to zero decreases from the load reactive power Q _r is the reactive power Q of the power system 1 in the first 22 sampling time T _S 22. Therefore, reactive power compensator 10 increases the output reactive power Q _O. Here, the output reactive power Q _O is larger than the reactive power upper limit value Q _H of the reactive power setting range Q _HL . Further, since the average value Σ of the output reactive power Q _O falls within the reactive power setting range Q _HL (Q _L <Σ <Q _H ), the reactive power compensator 10 changes the current output margin amount Q _i . do not do. The reactive power compensator 10 sets the current output reactive power Q _O at the 23rd sampling time T _S 23.

Subsequently, the reactive power compensator 10 maintains the output reactive power Q _O at the same value as the 22nd sampling time T _S 22 in the 23rd sampling time T _S 23. In addition, since the average value Σ of the output reactive power Q _O is higher than the reactive power upper limit value Q _H of the reactive power setting range Q _HL (Σ> Q _H ), the reactive power compensator 10 outputs the reactive power to a value smaller than Q _O. Therefore, reactive power compensator 10, the _{Q i} + Delta] Q _i plus reactive power variation range Delta] Q _i to the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} That is, the reactive power compensator 10 sets Q _O −ΔQ _i obtained by subtracting the change width ΔQ _i from the current output reactive power Q _O as the new output reactive power Q _O in the 24th sampling time T _S 24.

Subsequently, the reactive power compensator 10 sets the output reactive power Q _O to a value that is reduced by the change width ΔQ _i from the 23rd sampling time T _S 23 in the 24th sampling time T _S 24. In addition, since the average value Σ of the output reactive power Q _O is higher than the reactive power upper limit value Q _H of the reactive power setting range Q _HL (Σ> Q _H ), the reactive power compensator 10 outputs the reactive power to a value smaller than Q _O. Therefore, reactive power compensator 10, the _{Q i} + Delta] Q _i plus reactive power variation range Delta] Q _i to the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} That is, the reactive power compensator 10 sets Q _O −ΔQ _i obtained by subtracting the change width ΔQ _i from the current output reactive power Q _O as the new output reactive power Q _O in the 25th sampling time T _S 25.

Further, the reactive power compensator 10 sets the output reactive power Q _O to a value obtained by reducing the output reactive power Q _O by the change width ΔQ _i from the 24th sampling time T _S 24 in the 25th sampling time T _S 25. Further, since the average value Σ of the output reactive power Q _O falls within the reactive power setting range Q _HL (Q _L <Σ <Q _H ), the reactive power compensator 10 changes the current output margin amount Q _i . do not do. Therefore, the reactive power compensator 10 sets the current output reactive power Q _O also in the 26th sampling time T _S 26. Thereafter, reactive power compensator 10, if the output reactive power _{Q O} the average value sigma reactive power setting region within _{Q H-L} and _{(Q L <Σ <Q H} ), set the current output reactive power _{Q O} To do.

As described above, by setting the output tolerance amount Q _i to the output reactive power of the reactive power compensator 10 and bringing the output reactive power Q _O closer to the reactive power setting range Q _HL , the reactive power output is suppressed. it can. Since reactive power can be immediately output at the maximum of the output range regardless of whether it increases or decreases with respect to steep voltage fluctuations, steep voltage fluctuations can be suppressed.

As described above, according to the embodiment described above, the following effects can be obtained.
(1) sets the output reactive power Q reactive power upper limit value and below the _O Q _H and the reactive power lower limit value Q _L, the upper limit of reactive power upper limit value Q _H, ineffective to lower the reactive power limit value Q _L set the power setting region Q _H-L, the output reactive power Q _O to change the output reactive power Q _O so that reactive power setting region within Q _H-L stages. Therefore, since setting the outputs reactive power Q _O so that reactive power setting region within Q _H-L, can output reactive power width can afford rather than match the point of setting the reactive power. Therefore, the steady output of reactive power can be suppressed and it can respond to the further fluctuation | variation of active power and reactive power.

(2) The average value Σ of the output reactive power Q _O during the sampling time T _S is changed so as to approach the reactive power setting range Q _H−L . For this reason, the output reactive power Q _O can be suppressed, and further fluctuations in the active power and reactive power can be dealt with.

(3) When the output reactive power Q _O is not within the reactive power setting range Q _HL , the output margin amount Q _i is not changed, and when the output reactive power Q _O is outside the reactive power setting range Q _HL , the output margin is low. The output reactive power Q _O is changed by changing the measure Q _i stepwise. For this reason, the output of reactive power can be suppressed.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. 5 and 6. Reactive power compensator of this embodiment, the output Hiroshi the degree amount Q _i provided the upper and lower limits, these upper and lower limits and the output Hiroshi metric Q _i is the first in the point to be set to the value upon reaching This is different from the embodiment. Hereinafter, a description will be given focusing on differences from the first embodiment. Note that the reactive power compensator of this embodiment has the same configuration as the reactive power compensator of the first embodiment shown in FIG.

As shown in FIG. 5, first, the control device 14 of the reactive power compensator 10 performs the same processing as in the first embodiment until step S15 every time the sampling time T _S elapses.
Next, the controller 14 of the reactive power compensator 10 sets the output _tolerance amount setting area Q _MAX− in which the changed output tolerance amount Q _i is set by the output tolerance amount upper limit value Q _MAX and the output tolerance amount lower limit value Q _MIN. It is determined whether it is in the _MIN . That is, the control device 14 determines whether or not the output tolerance amount Q _i is smaller than the output tolerance amount lower limit value Q _MIN of the output tolerance amount setting area Q _MAX-MIN (step S16). When the output tolerance amount Q _i is smaller than the output tolerance amount lower limit value Q _MIN (step S16: YES), the control device 14 sets the output tolerance amount Q _i to the output tolerance amount lower limit value Q _MIN ( Step S18).

On the other hand, when the output tolerance amount Q _i is larger than the output tolerance amount lower limit value Q _MIN (step S16: NO), the control device 14 outputs the output tolerance amount Q _i in the output tolerance amount setting area Q _MAX-MIN . It is determined whether or not the tolerance amount upper limit value Q _MAX is larger (step S17). When the output tolerance amount Q _i is larger than the output tolerance amount upper limit value Q _MAX (step S17: YES), the control device 14 sets the output tolerance amount Q _i to the output tolerance amount upper limit value Q _MAX ( Step S19). On the other hand, the control unit 14, when the output Hiroshi metric _{Q i} is smaller than the output Hiroshi metric upper limit _{Q MAX:} (step S17 NO), the output Hiroshi metric _{Q i} is the output Yutaka metric within a predetermined range _{Q MAX-MIN} It is determined that there is an output, and the output reactive power Q _{O is set} to the current output margin amount Q _i (Q _i = Q _i ).

  Next, an operation mode of the reactive power compensator 10 when the reactive power compensator 10 configured as described above is installed in the power system 1 will be described. As shown in FIG. 6, a case where reactive power is generated in the power system 1 will be described.

First, the output tolerance amount Q _i of the reactive power compensator 10 is set to be displaced toward the advance (−) side. Further, in the power system 1, a little delay (+) reactive power is generated. Then, reactive power Q having a steep (+) delay is generated in the power system 1 at the 31st sampling time T _S 31. At this time, the reactive power compensator 10 proceeds to the power system 1 and outputs (−) reactive power. In other words, the reactive power compensator 10 outputs the output reactive power Q _O opposite in magnitude to the load reactive power Q _r of the power system 1. Further, since the average value Σ of the output reactive power Q _O is lower than the reactive power lower limit value Q _L of the reactive power setting range Q _HL , the reactive power compensator 10 has a value larger than the output reactive power Q _O. And Therefore, reactive power compensator 10, the _Q i -DerutaQ _i minus the reactive power variation range Delta] Q _i from the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} The set output tolerance amount Q _i matches the output tolerance amount lower limit value Q _MIN . That is, the reactive power compensator 10 sets Q _O + ΔQ _i obtained by adding the change width ΔQ _i to the current output reactive power Q _O as the new output reactive power Q _O in the 32nd sampling time T _S 32.

Subsequently, the reactive power compensator 10 sets the output reactive power Q _O to a value increased by the change width ΔQ _i from the 31st sampling time T _S 31 in the 32nd sampling time T _S 32. Further, since the average value Σ of the output reactive power Q _O is lower than the reactive power lower limit value Q _L of the reactive power setting range Q _HL (Σ <Q _L ), the reactive power compensator 10 outputs the reactive power and a value greater than Q _O. However, reactive power compensator 10 is pulled reactive power change width Delta] Q _i from the current output Hiroshi metric Q _i, becomes smaller than the output Hiroshi metric lower limit Q _MIN, reactive power compensator 10 is currently output Let the tolerance amount Q _i be Q _MIN . Therefore, the reactive power compensator 10 sets the current output reactive power Q _O also in the 33rd sampling time T _S 33.

Subsequently, the reactive power compensator 10 maintains the output reactive power Q _O at the same value as the 32nd sampling time T _S 32 at the 33rd sampling time T _S 33. Further, since the average value Σ of the output reactive power Q _O is lower than the reactive power lower limit value Q _L of the reactive power setting range Q _HL (Σ <Q _L ), the reactive power compensator 10 outputs the reactive power and a value greater than Q _O. However, reactive power compensator 10, catching and reactive power change width Delta] Q _i from the current output Hiroshi metric Q _i, becomes smaller than the output Hiroshi metric lower limit Q _MIN, reactive power compensator 10 is currently output Let the tolerance amount Q _i be Q _MIN . Therefore, the reactive power compensator 10 sets the current output reactive power Q _O also in the 34th sampling time T _S 34.

Further, the reactive power compensator 10 maintains the output reactive power Q _O at the same value as the 33rd sampling time T _S 33 at the 34th sampling time T _S 34. The load reactive power _{Q r} of the power system 1 in the first 34 sampling time _T S 34 is lowered from the reactive power Q. Therefore, reactive power compensator 10 increases the output reactive power Q _O. Here, the output reactive power Q _O is larger than the reactive power upper limit value Q _H of the reactive power setting range Q _HL . In addition, since the average value Σ of the output reactive power Q _O is higher than the reactive power upper limit value Q _H of the reactive power setting range Q _HL (Σ> Q _H ), the reactive power compensator 10 outputs the reactive power to a value smaller than Q _O. Therefore, reactive power compensator 10, the _{Q i} + Delta] Q _i plus reactive power variation range Delta] Q _i to the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} That is, the reactive power compensator 10 sets Q _O −ΔQ _i obtained by subtracting the change width ΔQ _i from the current output reactive power Q _O as the new output reactive power Q _O in the 35th sampling time T _S 35.

Subsequently, the reactive power compensator 10 sets the output reactive power Q _O at the 35th sampling time T _S 35 to a value that is smaller than the 34th sampling time T _S 34 by the change width ΔQ _i . Further, the average value Σ of the output reactive power Q _O falls within the reactive power setting range Q _HL (Q _L <Σ <Q _H ). Therefore, the reactive power compensator 10 sets the current output reactive power Q _O at the 36th sampling time T _S 36.

As described above, by setting the reactive power setting region Q _MAX-MIN output Hiroshi metric Q _i, it is possible to prevent the output Hiroshi metric Q _i unlimitedly by the voltage fluctuation of the electric power system continues to decrease or increase.

As described above, according to the embodiment described above, the following functions and effects can be achieved in addition to the functions and effects (1) to (3) of the first embodiment.
(4) Output Hiroshi if metric Q _i is the output Yutaka metric upper limit Q _MAX or set the output Yutaka metric Q _i to the output Hiroshi metric upper limit Q _MAX, the output Hiroshi metric Q _i is output Yutaka metric lower limit if the Q _MIN or less sets the output Yutaka metric _{Q i} to the output Hiroshi metric lower limit _{Q MIN.} For this reason, it is possible to suppress an excessive increase and decrease in the output tolerance amount Q _i due to the variation in the output reactive power Q _O. Therefore, it is possible to effectively use the region that can be output by the reactive power compensator 10 according to the load fluctuation. In other words, it is possible to reliably cope with further fluctuations in the reactive power of the power system.

(Third embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. The reactive power compensator of this embodiment has an upper limit and a lower limit for the system voltage V, and when the system voltage V reaches the upper limit and the lower limit, the reactive power compensator is set to that value as in the second embodiment. Is different. Hereinafter, the difference from the second embodiment will be mainly described. Note that the reactive power compensator of this embodiment has the same configuration as the reactive power compensator of the first embodiment shown in FIG.

As shown in FIG. 7, first, the control device 14 of the reactive power compensator 10 performs the same processing as in the second embodiment until step S19 every time the sampling time T _S elapses.
Next, the control device 14 of the reactive power compensator 10 determines whether or not the system voltage V is within the voltage setting range V _MAX-MIN set by the voltage upper limit value V _MAX and the voltage lower limit value V _MIN. . That is, the control device 14 determines whether or not the system voltage V is smaller than the voltage lower limit value V _{MIN of the} voltage setting range V _MAX-MIN (step S20). Then, when the system voltage V is smaller than the voltage lower limit value _VMIN (step S20: YES), the control device 14 performs constant voltage control to the voltage lower limit value _VMIN . (Step S22).

On the other hand, when the system voltage V is greater than the voltage lower limit value V _MIN (step S20: NO), the control device 14 determines whether the system voltage V is greater than the voltage upper limit value V _{MAX of the} voltage setting range V _MAX−MIN . It is determined whether or not (step S21). Then, when the system voltage V is higher than the voltage upper limit value V _MAX (step S21: YES), the control device 14 performs constant voltage control on the voltage upper limit value V _MAX (step S23). On the other hand, when the system voltage V is smaller than the voltage upper limit value V _MAX (step S21: NO), the control device 14 determines that the system voltage V is within the voltage setting range V _MAX-MIN , and the power factor Perform constant control.

Next, an operation mode of the reactive power compensator 10 when the reactive power compensator 10 configured as described above is installed in the power system 1 will be described. As shown in FIG. 8, a case where the system voltage V is equal to or higher than the voltage upper limit value V _MAX will be described.

First, the output tolerance amount Q _i of the reactive power compensator 10 is set to be displaced toward the advance (−) side. Then, the system voltage V of the power system 1 in _T S 41 41 sampling time is equal to or more than the voltage limit _{V MAX.} At this time, the reactive power compensator 10 outputs delayed (+) reactive power to the power system 1. In addition, the system voltage V shown with the broken line has shown the state when the reactive power compensation by the reactive power compensation apparatus 10 of this example is not performed.

Since the average value Σ of the output reactive power Q _O is higher than the reactive power upper limit value Q _H of the reactive power setting range Q _HL , the reactive power compensator 10 has a value smaller than the output reactive power Q _O. And Therefore, reactive power compensator 10, the _{Q i} + Delta] Q _i plus reactive power variation range Delta] Q _i from the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} However, the reactive power compensator 10 performs constant voltage control to the voltage upper limit value V _MAX because the system voltage V is greater than the voltage upper limit value V _MAX (V> V _MAX ). The current output reactive power Q _O is set at the 42nd sampling time T _S 42.

Subsequently, the reactive power compensator 10 maintains the output reactive power Q _O at the same value as the 41st sampling time T _S 41 at the 42nd sampling time T _S 42. Further, since the average value Σ of the output reactive power Q _O is higher than the reactive power upper limit value Q _H of the reactive power setting range Q _HL , the reactive power compensator 10 has a value smaller than the output reactive power Q _O. And Therefore, reactive power compensator 10, the _{Q i} + Delta] Q _i plus reactive power variation range Delta] Q _i from the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} However, the reactive power compensator 10 performs constant voltage control to the voltage upper limit value V _MAX because the system voltage V is greater than the voltage upper limit value V _MAX (V> V _MAX ). The current output reactive power Q _O is set at the 43rd sampling time T _S 43.

Subsequently, the reactive power compensator 10 maintains the output reactive power Q _O at the 43rd sampling time T _S 43 at the same value as the 42nd sampling time T _S 42. Further, since the average value Σ of the output reactive power Q _O is higher than the reactive power upper limit value Q _H of the reactive power setting range Q _HL , the reactive power compensator 10 has a value smaller than the output reactive power Q _O. And Therefore, reactive power compensator 10, the _{Q i} + Delta] Q _i plus reactive power variation range Delta] Q _i from the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} However, the reactive power compensator 10 performs constant voltage control to the voltage upper limit value V _MAX because the system voltage V is greater than the voltage upper limit value V _MAX (V> V _MAX ). The current output reactive power Q _O is set at the 44th sampling time T _S 44.

Furthermore, the reactive power compensator 10 maintains the output reactive power Q _O at the 44th sampling time T _S 44 at the same value as the 43rd sampling time T _S 43. Here, the system voltage V of the power system 1 decreases below the voltage upper limit value V _MAX at the 44th sampling time T _S 44. Therefore, reactive power compensator 10 performs the power factor constant control, reducing the output reactive power Q _O delay (+).

In addition, since the average value Σ of the output reactive power Q _O is higher than the reactive power upper limit value Q _H of the reactive power setting range Q _HL (Σ> Q _H ), the reactive power compensator 10 outputs the reactive power to a value smaller than Q _O. Therefore, reactive power compensator 10, the _{Q i} + Delta] Q _i plus reactive power variation range Delta] Q _i to the current output Hiroshi metric _{Q i} as a new output Hiroshi metric _{Q i.} That is, the reactive power compensator 10 sets Q _O −ΔQ _i obtained by subtracting the change width ΔQ _i from the current output reactive power Q _O as the new output reactive power Q _O in the 45th sampling time T _S 45.

Subsequently, the reactive power compensator 10 sets the output reactive power Q _O to a value that is reduced by the change width ΔQ _i from the 44th sampling time T _S 44 in the 45th sampling time T _S 45. Further, the average value Σ of the output reactive power Q _O falls within the reactive power setting range Q _HL (Q _L <Σ <Q _H ). Therefore, the reactive power compensator 10 sets the current output reactive power Q _O at the 46th sampling time T _S 46. Thereafter, reactive power compensator 10, if the output reactive power _{Q O} the average value sigma reactive power setting region within _{Q H-L} and _{(Q L <Σ <Q H} ), set the current output reactive power _{Q O} To do.

As described above, by setting the voltage setting range V _MAX-MIN to the system voltage V, it is possible to suppress the system voltage V from deviating from a normal voltage.
As described above, according to the embodiment described above, in addition to the functions and effects of (1) to (3) of the first embodiment and (4) of the second embodiment, the following functions and effects can be achieved.

(5) The voltage upper limit value V _MAX and the voltage lower limit value V _MIN are set, the voltage upper limit value V _MAX is set as the upper limit, the voltage lower limit value V _MIN is set as the lower limit, and the voltage setting range V _MAX-MIN is set. Voltage constant control is performed so that the voltage V is within the voltage setting range V _MAX-MIN . For this reason, it is possible to prevent the system voltage V from fluctuating greatly.

In addition, the said embodiment can be implemented with the following forms which changed this suitably.
In the above embodiment, the sampling time _{T S,} change width Delta] Q _i of the output Hiroshi metric _{Q i,} the reactive power limit value _{Q L,} reactive power upper limit value _{Q H,} the output Hiroshi metric lower limit _{Q MIN,} the output Hiroshi metric upper limit Q Values such as _MAX , voltage lower limit value V _MIN , voltage upper limit value V _MAX can be arbitrarily set according to the installation location.

In the above embodiment, the absolute power difference between the reactive power lower limit value Q _L and the reactive power upper limit value Q _H may be set to an arbitrary value individually.
In the second embodiment, the output Yutaka metric lower limit Q _MIN output Yutaka metric upper limit Q _MAX may be set to any value individually the difference in absolute value between zero.

In the above embodiment, the output tolerance amount Q _i is set, but the output reactive power Q _O may be changed without using the output tolerance amount Q _i .
In the above embodiment, it is determined whether or not the average value Σ of the output reactive power Q _O within the sampling time T _S is within the reactive power setting range Q _HL and the output reactive power Q _O is changed stepwise. did. However, not only the mean value Σ of the output reactive power Q _O at the sampling time T _S, determines whether the output reactive power Q _O in a particular time of sampling time T _S is the reactive power setting region Q _H-L May be.

In the above embodiment, the output reactive power Q _O but has performed whether the reactive power setting region within Q _H-L in the sampling time T _S, the output reactive power Q _O reactive power setting region Q _H-L It may be determined at any time whether or not it is within.

  In the above embodiment, one reactive power compensator 10 is installed in one power system 1, but the same effect can be obtained even when a plurality of devices are installed.

DESCRIPTION OF SYMBOLS 1 ... Electric power system, 2 ... Switch, 3 ... Transformer, 4 ... Load, 10 ... Reactive power compensator (SVG), 11 ... Inverter, 12 ... Interconnection reactor, 13 ... Capacitor, 14 ... Control device, CT ... Current sensor, PT ... Voltage sensor, A ... Output command value, Q _i ... Output tolerance, ΔQ _i ... Change range of output tolerance, Q _H ... Reactive power upper limit, Q _L ... Reactive power lower limit, Q _{H- L} ... reactive power setting range, Q _MAX ... output tolerance amount upper limit value, Q _MIN ... output tolerance amount lower limit value, Q _MAX-MIN ... output tolerance amount setting range, V ... system voltage, V _MAX ... voltage upper limit value, V _MIN ... Voltage lower limit value, V _MAX-MIN ... Voltage setting range, T _S ... Sampling time as a fixed time.

Claims (5)

In the reactive power compensator of constant power factor control system that outputs reactive power to the power system to stabilize the system voltage of the power system,
Set the reactive power upper limit value and the reactive power lower limit value above and below the output reactive power, set the reactive power upper limit value as the upper limit, and set the reactive power setting range with the reactive power lower limit value as the lower limit.
The reactive power compensator, wherein the output reactive power is changed stepwise so that the reactive power is within the reactive power setting range. The reactive power compensator according to claim 1,
The reactive power compensator characterized by changing so that the average value of the output reactive power in a certain period of time approaches the reactive power setting range. The reactive power compensator according to claim 1 or 2,
Set the output margin amount to give margin to the output reactive power,
When the output reactive power is within the reactive power setting range, the output margin amount is not changed, and when the output reactive power is outside the reactive power setting range, the output margin amount is changed stepwise to thereby invalidate the output. A reactive power compensator characterized by changing power. In the reactive power compensator according to any one of claims 1 to 3,
Set the output margin amount to give margin to the output reactive power,
While setting the output tolerance amount upper limit value as the upper limit value of the output tolerance amount and the output tolerance amount lower limit value as the lower limit value of the output tolerance amount,
Set an output tolerance amount setting area with the output tolerance amount upper limit as an upper limit and the output tolerance amount lower limit as a lower limit,
When the output tolerance amount is equal to or greater than the output tolerance amount upper limit value due to the change of the output reactive power, the output tolerance amount is set to the output tolerance amount upper limit value, and the output tolerance amount is set to the output tolerance amount lower limit value. The reactive power compensator according to claim 1, wherein the output tolerance amount is set to the output tolerance amount lower limit value when the value is less than or equal to a value. In the reactive power compensator according to any one of claims 1 to 4,
Set the voltage upper limit value and the voltage lower limit value, set the voltage setting range with the voltage upper limit value as the upper limit and the voltage lower limit value as the lower limit,
When the system voltage deviates from the voltage setting range, a constant voltage control is performed so that the system voltage is within the voltage setting range.

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