JPH04333112A - Cooperative controller for static reactive power compensator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a static var power compensator connected to an electric power system, which maintains the system voltage and improves the stability of the system.

0002

[Background Art] In recent years, in order to maintain the voltage of the power system,
A static var compensator (hereinafter referred to as SVC) is installed. FIG. 2 shows a single line diagram of a conventional SVC and a block diagram of a control device. In the figure, 1 is the busbar of the substation in the power system, 2 is the voltage transformer, 3 is the current transformer, and 4 is the SV
5 is a step-down transformer, 6 is a thyristor control reactor (hereinafter referred to as TCR), and 7 is a phase adjustment capacitor. Further, 41 is a voltage detection circuit, 42 is a voltage reference circuit, 43 and 46 are addition circuits, 44 is a current detection circuit, and 4
5 is a slope reactance circuit, 47 is a transfer function circuit,
48 is a Q-α function generating circuit, 49 is an ignition pulse generating circuit, 61 is a reactor, and 62 and 63 are thyristors.

Next, the principle of operation will be explained. The voltage transformer 2 detects the voltage of the power system 1, and the SVC control device 4 supplies phase-advanced reactive power when the system voltage decreases, and conversely supplies phase-advanced reactive power when the voltage increases. Thus, the system voltage can be maintained by controlling the phase of the thyristors 62 and 63 of the TCR 6. For this purpose, the output of the voltage transformer 2 is converted to an effective value or an average value through a voltage detection circuit 41, the output is compared with the output of a voltage reference circuit 42 in an adder circuit 43, and the deviation is sent via an adder circuit 46. and is input to the transfer function circuit 47. The transfer function circuit 47 is composed of a proportional-integral circuit and the like, and is a part that determines the response characteristics of the SVC.

The output of the transfer function circuit 47 is converted by a Q-α function circuit 48 into a value corresponding to the control phase of the corresponding thyristors 62 and 63 of the TCR 6 based on the reactive power standard, and further a gate pulse is given by a firing pulse generation circuit 49. ing. Further, the SVC current detected by the current transformer 3 is transmitted to the current detection circuit 4.
4 into an effective value or an average value, and after being calculated by a slope reactance circuit 45, an addition circuit 46
is input to determine the VI characteristic of the SVC.

[0005] The operation of the above SVC will be further explained using FIG. 3. In Figure 3(a), reactor 6 is connected between O and A.
1 is opened by the thyristors 62 and 63, and the output current is determined only by the phase adjusting capacitor 7. That is, a region where the phase-advanced reactive current is proportional to the voltage, a region between A and B where constant voltage characteristics are maintained by the phase control of the thyristors 62 and 63, and a region between B and C where the current of the reactor 61 is controlled by the thyristors 62 and 63. This is the region where the slow phase reactive current changes in proportion to the voltage when the maximum flow is possible. In addition, A-
The slope between B is determined by the gain of the slope reactance circuit 45, and the slope between S and B is determined by the gain of the slope reactance circuit 45.
It is set so that 100% of the VC capacity can be controlled.

[0006]

[Problem to be solved by the invention] By the way, the above-mentioned SVC
If there are multiple units on the same bus or close to each other in a substation in the power system, logically the V shown in Figure 3(a)
- Although the device operates at the same operating point of the -I characteristic, the reality is that the operating point varies due to various factors such as errors in manufacturing or adjustment. In other words, when the slope between A and B is small (slope reactance is small), the output current of the SVC changes greatly even with a slight voltage deviation. With SVC, one operating point is point D, which supplies a phase-advanced reactive current, and the other operating point is point D, i.e.,
When viewed from the system side, the SVC operates in the opposite way, such as supplying a slow phase reactive current (loss in the step-down transformer increases). ).

[0007] Furthermore, when the operating points change and one becomes point E and the other becomes point E', the SVC at point E is already outside the constant voltage control region, so the voltage maintenance effect against voltage fluctuations is This is undesirable because the total response of both SVCs changes when viewed from the system side. The present invention has been made to solve the above-mentioned problems, and is
It is an object of the present invention to provide a cooperative control device for SVCs that can balance the operating currents of VCs.

[Configuration of the invention]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a control device for the plurality of SVCs including a circuit for detecting a current deviation, a circuit for calculating the deviation, and a control device. Cooperative control is configured by adding an injection circuit to correct the signal. [Operation] When the output current of each SVC becomes unbalanced by the above means, calculate the deviation of the current,
Correct the signal of the SVC control device in a direction that balances the output current.

[0009]

[Examples] Examples of the present invention will be described below. FIG. 1 is a single line diagram of an SVC and a block diagram of a cooperative control device showing an embodiment of the present invention. In FIG. 1, the same elements as in FIG. 2 are given the same reference numerals. However, in Figure 1, SV
Although one C unit is shown, Figure 2 shows two SVC units, so for convenience, the one with the suffix -1 is the parent S.
The VC with the suffix -2 will be called a child SVC to distinguish it. The different parts from FIG. 2 will be explained below. 8 is a cooperative control device, 81 is a current detection circuit, 82
, 84 is an adder circuit, and 83 is an arithmetic circuit, in which an integrator or the like is used.

Next, the operation will be explained. In the above configuration, the current detection circuit 81 is the output of the current transformer 3-1, that is,
The current of the parent SVC is converted into an effective value or an average value, the adder 82 detects the difference between the parent SVC current and the child SVC current (i.e., the output of the current detection circuit 44), and the arithmetic circuit 83 detects the difference between the child SVC current and the child SVC current. Calculation is performed so that the SVC current stably follows the parent SVC current.

The calculation result is added to the child SV by the adder circuit 84.
As a result, the output of the control device 4-2 is corrected, and furthermore, the control phase of the thyristor control reactor 6-2 is changed, so the operating current of the child SVC is corrected. It follows the current of the parent SVC. According to this embodiment, when two SVCs are on the same bus in the power system, the operating current of the child SVC is changed to that of the parent SVC.
can be made to follow, and as a result, cooperative operation between the two can be maintained.

[0012] In the above embodiment, two SVCs are connected to the same bus, but even if they are located close to each other, they can perform cooperative operations with a similar configuration. Furthermore, when three or more SVCs are on the same bus or in close proximity, overall cooperative operation can be maintained by making one the parent and the others child SVCs with the same configuration as in the previous embodiment. Can be done. Furthermore, when the first SVC is the parent and the other two SVCs are the children, a method of passing the current of the second SVC to the third SVC can also be considered.

[0013] If there is a synchronous phase modifier or generator on the same bus as the SVC or in a location close to it, the reactive currents of these are detected and injected into the adder circuit 82 instead of the output of the current detection circuit 81. By doing so, the operation of the SVC can be coordinated with the synchronous phase modifier and the generator. In the embodiment of FIG. 1, the output of the arithmetic circuit 83 is injected into the adder circuit 84 and the child SV
Although the current correction of C is performed, the addition circuit 46 is used instead.
Alternatively, the same effect can be obtained even if the injection is performed at the injection point 43 by changing the transfer function of the arithmetic circuit 83 depending on the injection point. Also, if the output of the current detection circuit of the parent SVC is used, the child SVC
It goes without saying that the VC current detection circuit 81 can be omitted.

[0014]

[Effects of the Invention] As described above, according to the present invention, other S
The configuration allows the operating current to follow by calculating the current deviation from the VC and correcting the output, so multiple SV
It is possible to provide an SVC cooperative control device that can balance the operations of C.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an SVC and a cooperative control device showing an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional SVC.

FIG. 3 is a diagram illustrating the operation of a conventional SVC.

[Explanation of symbols]

1 Power system 2 Voltage transformer 3, 3-1, 3-2 Current transformer 4, 4-1, 4-2 SVC control device 5, 5-
1, 5-2 Step-down transformer 6, 6-1, 6-2
Thyristor control reactor 7, 7-1, 7-2
Phase adjustment capacitor 8 Coordination control device 41 Voltage detection circuit 43 Voltage reference circuit 43, 46, 82, 84 Addition circuit 44, 81 Current detection circuit 45 Slope reactance circuit 47 Transfer function circuit 48, Q-α function generation circuit 49 Ignition Pulse generation circuit 61 Reactor 62, 63 Thyristor 83 Arithmetic circuit

Claims (1)

[Claims] Claim 1: When two sets of static reactive power compensators, which control the reactive power generated by controlling the current flowing through the reactor using a semiconductor switch, are grounded in the same substation or in close proximity, each static reactive power compensator A static var power compensator characterized in that the operations of both static var power compensators are coordinated by detecting the currents of the power compensators, calculating their deviation, and injecting it into one control circuit. Coordination control device.