JP2011030382A - Reactive power compensator and output sharing method for the reactive power compensator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactive power compensator that effectively shares output with respect to a plurality of compensators, or an output sharing method for the same. <P>SOLUTION: The reactive power compensator is connected to a power system. The reactive power compensator has a plurality of compensators respectively which stabilize a voltage or a current of the power system on the basis of a voltage output by the reactive power compensator or a current flowing in the power system, a priority-order determining part 1 for determining the output priority order n which is assigned to share a compensation capacity of the reactive power compensator for each of the plurality of compensators, and a sharing-amount arithmetic assignment part 2 which shares the output of the reactive power compensator by the computation formula Sn+1=Sn-Vn (n=1, 2, 3, 4 ...) (1) (however, Sn+1 is a remaining capacity of the reactive power compensator, Sn is a current capacity of the reactive power compensator, and Vn is output power of an n-th compensator in the plurality of prioritized compensators) on the basis of the priority order determined by the priority-order determining part and sets Vn=Sn if it is Sn+1<0. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reactive power compensator including a plurality of compensators, and relates to, for example, output sharing of a plurality of compensators.

  In recent years, dissemination and expansion of distributed power sources such as solar power generation and wind power generation are rapidly progressing in response to global environmental problems. In the future, there are concerns that the power quality of the power system will be adversely affected if a large number of distributed power sources are connected to the power system. There are self-excited reactive power compensators (SVCs (Static Var Compensators)) or active filters for power as shown in FIG. 4 to compensate for the adverse effects of the power quality.

  In FIG. 4, a self-excited reactive power compensator 11 (hereinafter referred to as reactive power compensator 11) connected to a power system (distribution system) 10 includes an interconnection transformer 12 having one end connected to the power system 10. A reactor 13 having one end connected to the other end of the interconnection transformer 12, a self-excited inverter 14 connected to the other end of the reactor 13, and a control circuit 15 for controlling the self-excited inverter 14 are provided.

  The control circuit 15 includes an output voltage V of the reactive power compensator 11 detected by a voltage detector (not shown), a current IL flowing through the power system 10 detected by a current detector (not shown), and a current detector (not shown). The output current I of the self-excited inverter 14 detected by the above is input. The control circuit 15 generates a signal for controlling the self-excited inverter 14 based on these inputs.

  When an apparatus as shown in FIG. 4 is installed for each of the distributed power sources, there is a problem of cost or installation location, and voltage fluctuation, harmonic voltage or current, without changing the circuit configuration as shown in FIG. A multi-functional reactive power compensator having a compensation function capable of dealing with unbalanced voltage or current, flicker and the like has been proposed.

  However, such reactive power compensator has a limit in the capacity that can be output. For this reason, since the number of compensation functions has increased, it is necessary to increase the capacity in order to output the compensation amount necessary for all compensation functions. In this case, the cost increases as the reactive power compensator increases in size. There are problems such as. As countermeasures, various output sharing methods for outputting within the rated capacity of a limited reactive power compensator have been proposed (for example, Patent Documents 1 to 4).

Japanese Patent Application Laid-Open No. H08-11937. Japanese Patent Application Laid-Open No. H10-1111725. JP-A H10-243561. Japanese Patent Application Laid-Open No. H11-18299.

  FIG. 5 is a schematic diagram of the control circuit 15 of FIG.

  The control circuit 15 includes a voltage fluctuation compensation calculation unit 20, a harmonic voltage (current) compensation calculation unit 21, an unbalanced voltage (current) compensation calculation unit 22, and a flicker compensation calculation unit 23 (hereinafter, reference numerals 20 to 23 are collectively compensated). Also, it is provided with a shared quantity calculation unit 24, a limiter unit 25, an adder 26, an ACR 27, and a PWM control circuit 28.

  The voltage fluctuation compensation calculation unit 20 calculates a compensation current command value that compensates for the voltage fluctuation of the power system 10 based on the output voltage V of the reactive power compensator 11.

  The harmonic voltage (current) compensation calculation unit 21 calculates a compensation current command value that compensates for the harmonic voltage (current) of the power system 10 based on the current IL flowing through the power system 10.

  The unbalanced voltage (current) compensation calculation unit 22 calculates a compensation current command value that causes the power system 10 to be three-phase balanced based on the current IL flowing through the power system 10.

  The flicker compensation calculation unit 23 calculates a compensation current command value that compensates for flicker based on the output voltage V of the reactive power compensator 11 and the current IL flowing through the power system 10.

  The assigned amount calculation unit 24 determines the output power output from the compensators 20 to 23 according to a predetermined calculation formula, and outputs the result to the limiters 25 a to 25 d of the limiter unit 25.

  The limiter unit 25 includes limiters 25a to 25d, and the sharing amount calculation unit 24 determines limit values of the limiters 25a to 25d for the compensators 20 to 23. Compensation current command values of the compensators 20 to 23 are limited by the limiters 25 a to 25 d and output to the adder 26.

  The adder 26 outputs a signal obtained by adding all the signals of the limiters 25a to 25d to the ACR 27.

  The ACR 27 generates a voltage command for the self-excited inverter 14 based on a deviation signal between the compensation current command value output from the limiter unit 25 via the adder 26 and the output current I of the self-excited inverter 14, and the PWM control circuit To 28.

  The PWM control circuit 28 generates a gate signal based on the voltage command from the ACR 27 and transmits it to the self-excited inverter 14.

  In the sharing method as shown in FIG. 5, the sharing amount calculation unit 24 adjusts the sharing amount so that output can be performed within the apparatus capacity by providing an output limiter for each compensation function. The share ratio calculated by the share amount calculation unit 24 is determined by a fixed value or a ratio of the sum of the compensation amount and the compensation capacity.

  Even the conventional method has a certain compensation effect. However, there are various events to be compensated depending on the installation location, and when assigning a compensation amount to any compensation function, there is a drawback in that the compensation effect of the event to be compensated is lowered.

  The present invention has been made based on the above-described problems, and provides a reactive power compensator that can effectively share outputs to a plurality of compensators or an output sharing method thereof.

  In order to solve the above-described problem, the present invention is a reactive power compensator connected to an electric power system, the voltage of the electric power system based on a voltage output from the reactive power compensator or a current flowing through the electric power system. A plurality of compensators for stabilizing voltage or current, a priority determining unit for determining a priority n of outputs of the plurality of compensators allocated for compensation capacity sharing of the reactive power compensator, and the priority Sn + 1 = Sn−Vn (n = 1, 2, 3, 4...) (1) (where Sn + 1 is the remaining capacity of the reactive power compensator, and Sn is the current The reactive power compensator capacity, Vn is an output power of the nth compensator among the plurality of prioritized compensators. Sn + 1 If 0 is characterized in that a control unit and a sharing amount calculating assignment unit to Vn = Sn.

  In addition, the output sharing method of the reactive power compensator of the present invention includes a plurality of compensators connected to the power system and stabilizing the voltage or current of the power system, a priority determining unit, and a shared amount calculation assigning unit. An output sharing method for a reactive power compensator, wherein the priority determination unit determines a priority n of outputs of the plurality of compensators allocated for compensation capacity sharing of the reactive power compensator, and the sharing The quantity calculation allocation unit is Sn + 1 = Sn−Vn (n = 1, 2, 3, 4,...) (1) (where Sn + 1 is the reactive power) according to the priority determined by the priority determination unit. The reactive power is calculated by the following equation: Remaining capacity of the compensator, Sn is the current capacity of the reactive power compensator, and Vn is the output power of the nth compensator among the plurality of prioritized compensators. Sharing the output of the compensation device In this case, characterized by the Vn = Sn if Sn + 1 <0.

  According to the above configuration, priority is provided to a plurality of compensators. Then, the output of the reactive power compensator is shared by a plurality of compensators according to the equation (1), the remaining capacity of the reactive power compensator is calculated for each compensator, and finally the output of the reactive power compensator is the reactive power. Each compensator is assigned within the range of the rated capacity of the compensator. Further, when Sn + 1 <0, the output power of the corresponding compensator is limited.

  As a result, the reactive power compensator can be assigned according to priority without exceeding the rating of the reactive power compensator, and the device capacity of the reactive power compensator can be assigned with the highest priority to the necessary compensation function. Can be compensated 100%. Even if the compensation function is increased, it is possible to easily share the capacity of the reactive power compensator simply by specifying the priority order.

  In addition, when there are a plurality of the same priorities among the priorities, the shared amount calculation assigning unit sets the output power Vn of the plurality of compensators having the same priorities to Vn = Vnm + Vn (m + 1) +. m is 1, Vnm is the output power of the plurality of compensators m of the same priority having the nth priority, Vn (m + 1) is the output power of the plurality of compensators m + 1 having the same priority of the nth priority, and priority. In this case, if Sn + 1 <0 in equation (1), the output power Vnm of each of the compensators having the same priority is: Vnm = Vnm / Vn * Sn (m = 1, 2, 3, 4...)

  Further, in the output sharing method of the reactive power compensator of the present invention, the sharing amount calculation assigning unit determines the output power Vn of the plurality of compensators having the same priority when there are a plurality of the same priorities. Vn = Vnm + Vn (m + 1) + (where m is 1, Vnm is the output power of the plurality of compensators m with the same priority n, and Vn (m + 1) is the plurality with the nth priority. , The output power of the compensator m + 1 having the same priority, and the same after the nth compensator m + 2 of the priority). In this case, if Sn + 1 <0 in Equation (1), the plurality of the same The output power Vnm of each compensator having priority is calculated by Vnm = Vnm / Vn * Sn (m = 1, 2, 3, 4,...).

  According to the above configuration, the capacity of the reactive power compensator is assigned to the compensator even if there are overlapping priorities among the priorities of the plurality of compensators.

  As a result, even when the priorities overlap, the capacity of the reactive power compensator can be assigned to the overlapping compensators.

  According to the invention of claim 1 or 3, priority is provided to a plurality of compensators. Then, the output of the reactive power compensator is shared by a plurality of compensators according to the equation (1), the remaining capacity of the reactive power compensator is calculated for each compensator, and finally the output of the reactive power compensator is the reactive power. Each compensator is assigned within the range of the rated capacity of the compensator. Further, when Sn + 1 <0, the output power of the corresponding compensator is limited.

  As a result, the reactive power compensator can be assigned according to priority without exceeding the rating of the reactive power compensator, and the device capacity of the reactive power compensator can be assigned with the highest priority to the necessary compensation function. Can be compensated 100%. Even if the compensation function is increased, it is possible to easily share the capacity of the reactive power compensator simply by specifying the priority order.

  According to the second or fourth aspect of the present invention, the capacity of the reactive power compensator is assigned to the compensator even if there are overlapping priorities among the priorities of the plurality of compensators.

  As a result, even when the priorities overlap, the capacity of the reactive power compensator can be assigned to the overlapping compensators.

The block diagram of the control circuit which has multi-function compensation in this Embodiment. The flowchart for demonstrating the process of the control circuit in the implementation excitation 1. FIG. The flowchart for demonstrating the process of the control circuit in the implementation excitation 2. FIG. The block diagram of a self-excited reactive power compensation apparatus. The block diagram of the control circuit which has the conventional multi-function compensation.

  Hereinafter, a reactive power compensator according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration diagram of a control circuit 3 of the reactive power compensator according to the present embodiment. The same components as those in FIG. The difference from FIG. 5 is that a priority order determining unit 1 and a shared amount calculation assigning unit 2 are provided instead of the shared amount calculating unit 24 and the limiter unit 25. The control circuit 3 corresponds to control means.

  The priority order determination unit 1 gives priority order n to the compensators 20 to 23. For example, in the case of FIG. 1, since there are four compensators, a priority order of 1 to 4 (1 is the highest priority) is given.

  The assigned amount calculation assigning unit 2 assigns the capacity of the reactive power compensator to the compensators 20 to 23 based on the priority determined by the priority determining unit 1 by a process described later.

  The following processes of the first and second embodiments are performed by such an apparatus configuration.

  With reference to FIG. 2, the processing of the shared amount calculation assigning unit 2 in the present embodiment will be described. Here, the rated capacity of the reactive power compensator is S, the current capacity of the reactive power compensator is Sn, the remaining capacity of the reactive power compensator after being assigned for each priority is Sn + 1, and each compensator is given priority. Is set to Vn (n = 1, 2, 3, 4,...).

  First, 1 which is the highest priority is substituted for n. Also, the rated capacity S is substituted for the capacity S1 of the current reactive power compensator (STEP 1).

next,
Sn + 1 = Sn−Vn (when Sn + 1 ≧ 0) (1)
The capacity | capacitance of a reactive power compensator is shared by the compensators 20-23 by Formula (1). Since n = 1, S1-V1 is substituted for the remaining capacity S2 (STEP 2).

Next, it is determined whether or not the remaining capacity S2 is negative (STEP 3). If S2 ≧ 0, the process proceeds to STEP 5. In the case of S2 <0, Vn = Sn (2)
Equation (2) limits the output power of the compensator. Since n = 1, S1 is substituted for the output power V1 of the compensator with priority 1 (STEP 4).

  Next, 2 which is the next priority is substituted for n (STEP 5).

  Next, it is determined whether or not n exceeds the maximum value of the priority (STEP 6). If n exceeds the maximum value of the priority, the process is terminated. Otherwise, the process returns to STEP 2 and n is the maximum value. Steps 2 to 6 are repeated until.

  In the present embodiment, the case where there are four compensators has been described, but the case where n ≧ 2 is also applicable.

  Thus, in the present embodiment, priorities are provided for the compensators 20 to 23. Then, the capacity of the reactive power compensator is shared by the compensators 20 to 23. When Sn + 1 <0, the output power of the corresponding compensators 20 to 23 is limited by the equation (2).

  As a result, the reactive power compensator can be assigned according to priority without exceeding the rating of the reactive power compensator, and the device capacity of the reactive power compensator can be assigned with the highest priority to the necessary compensation function. Can be compensated 100%. Even if the compensation function is increased, it is possible to easily share the capacity of the reactive power compensator simply by specifying the priority order.

  A priority order is assigned by the priority order determination unit 1, and at this time, a duplicate priority order may be included (for example, 1, 2, 2, 3).

  FIG. 3 shows the processing of this embodiment. The difference from the first embodiment is that the processing of STEPs 7 to 10 to be performed when the priorities overlap is added.

  After STEP 1, it is determined whether or not there are a plurality of priorities (STEP 7). If the priorities do not overlap, the process proceeds to STEP2. On the other hand, if the priorities overlap, the process proceeds to STEP8.

In STEP 7, when the priorities are overlapped, the output power Vn of the compensator is set to Vn = Vnm + Vn (m + 1) + (m is 1) (3)
It calculates by Formula (3) (STEP8).
Here, Vnm represents the output power of the n-th order compensator m, and Vn (m + 1) represents the output power of the n-th order compensator m + 1. Since m + 2 is omitted, all the nth overlapping compensators are added.

  Next, when Sn + 1 <0 in STEP3, the process proceeds to STEP9 having the same processing contents as STEP7. If the priorities do not overlap, the process proceeds to STEP4. On the other hand, if the priorities overlap, the process proceeds to STEP10.

In STEP 9, when the priority order is duplicated,
Vnm = Vnm / Vn * Sn (m = 1, 2, 3, 4,...) (4)
The output power Vnm of each compensator having the same priority order is calculated according to equation (4) (STEP 10). Formula (4) is calculated for each of the overlapping priorities.

  Thus, in this embodiment, even if there are overlapping priorities among the priorities of the compensators 20 to 23, the capacity of the reactive power compensator is given to the compensators 20 to 23 by the equations (3) and (4). Assigned.

  As a result, in addition to the effects of the first embodiment, the reactive power compensator capacity can be assigned to the overlapping compensators even when the priorities overlap.

Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... Priority order determination part 2 ... Allocation amount calculation allocation part 3, 15 ... Control circuit 10 ... Electric power system 11 ... Reactive power compensation apparatus 12 ... Interconnection transformer 13 ... Reactor 14 ... Self-excited inverter 20 ... Voltage fluctuation compensation calculation part 21... Harmonic voltage (current) compensation calculation unit 22... Unbalanced voltage (current) compensation calculation unit 23... Flicker compensation calculation unit 24 .. Allocation amount calculation unit 25... Limiter units 25a to 25d.
28 ... PWM control circuit

Claims (4)

A reactive power compensator connected to a power system,
A plurality of compensators for stabilizing the voltage or current of the power system based on the voltage output from the reactive power compensator or the current flowing through the power system;
A priority determining unit that determines the priority n of the outputs of the plurality of compensators assigned to share the compensation capacity of the reactive power compensator;
Sn + 1 = Sn−Vn (n = 1, 2, 3, 4,...) (1) according to the priority determined by the priority determining unit.
(Where Sn + 1 is the remaining capacity of the reactive power compensator, Sn is the current capacity of the reactive power compensator, and Vn is the output power of the nth compensator among the plurality of prioritized compensators)
Share the output of the reactive power compensator with the following formula:
In this case, the reactive power compensator includes a control unit having a shared amount calculation assigning unit that sets Vn = Sn if Sn + 1 <0. When there are a plurality of the same priorities among the priorities, the shared amount calculation assigning unit sets the output power Vn of the compensators having the same priorities to Vn = Vnm + Vn (m + 1) +.
(Where m is 1, Vnm is the output power of the plurality of compensators m of the same priority having the nth priority, and Vn (m + 1) is the output of the plurality of compensators m + 1 having the same priority of the nth. (The same applies to power and priority nth compensator m + 2 and later)
Calculated by the following formula:
In this case, if Sn + 1 <0 in Equation (1), the output power Vnm of each of the plurality of compensators having the same priority is
Vnm = Vnm / Vn * Sn (m = 1, 2, 3, 4...)
The reactive power compensator according to claim 1, calculated by: A reactive power compensator output sharing method comprising a plurality of compensators connected to an electric power system and stabilizing a voltage or current of the electric power system, a priority determining unit, and a shared amount calculation assigning unit,
The priority determining unit determines the priority n of the outputs of the plurality of compensators assigned to share the compensation capacity of the reactive power compensator;
The shared amount calculation assigning unit is Sn + 1 = Sn−Vn (n = 1, 2, 3, 4...) (1) according to the priority determined by the priority determining unit.
(Where Sn + 1 is the remaining capacity of the reactive power compensator, Sn is the current capacity of the reactive power compensator, and Vn is the output power of the nth compensator among the plurality of prioritized compensators)
The reactive power compensator output sharing method according to claim 1, wherein the output of the reactive power compensator is shared, and in this case, if Sn + 1 <0, Vn = Sn. When there are a plurality of the same priorities among the priorities, the shared amount calculation assigning unit determines the output power Vn of the plurality of compensators having the same priorities as Vn = Vnm + Vn (m + 1) +.
(Where m is 1, Vnm is the output power of the plurality of compensators m of the same priority having the nth priority, and Vn (m + 1) is the output of the plurality of compensators m + 1 having the same priority of the nth. (The same applies to the power and the nth compensator m + 2 after priority)
In this case, if Sn + 1 <0 in equation (1), the output power Vnm of each compensator having the same priority is
Vnm = Vnm / Vn * Sn (m = 1, 2, 3, 4...)
The output sharing method of the reactive power compensator according to claim 3, wherein the output sharing method is calculated by:

Images