JPS6169335A - Controller of stationary reactive power control device - 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] [Field of Application of the Invention] The present invention relates to a control device for a static reactive power control device, and particularly to a control device for a static reactive power control device suitable for widening the stable operation range of a load. Regarding.

[Background of the invention]

BACKGROUND OF THE INVENTION As power systems become larger and wider in area, the adjustment of reactive power in power systems has become an extremely important issue, and static reactive power control devices using thyristors have been developed. The most widely used static reactive power control device is the type shown in FIG. 2 in which reactor current is controlled by phase control of a thyristor. In the figure, 1 is the load power source, 2 is the impedance of the transmission line, 3 is the load, 4 is the phase advance capacitor, 5 is the step-down transformer, 6 is the thyristor-controlled static reactive power control device, 61 is the reactor, 62 is a thyristor for phase control. 7 is a voltage transformer that detects the magnitude of the voltage connected to the load 3; 8 is a control device for a static reactive power control device; 81 is a voltage set value Vref that calculates the difference between the detected value V of the voltage transformer 7; An adder circuit 82 is an arithmetic circuit that performs control calculations such as first-order delay, and 83 is a phase control circuit that outputs a pulse with an appropriate phase in proportion to the magnitude of the output of the arithmetic circuit 82. An example is shown in FIG. Figure 3 shows the phase characteristics of the output pulse with respect to the input, and the input is VU. In the following cases, the pulse phase is the minimum value α of the firing angle. , 74 or more, the maximum firing angle α128. The input is Vyu. and v mat, a pulse having a firing angle proportional to the input signal is output.

84 is a pulse amplifier circuit that amplifies the output pulse of the phase control device 83, and this output becomes the phase control pulse of the thyristor 62. The example in Figure 2 is, for example, "Nissin Electric Wave Phase"
VoQ28. Nci3. ('83, 9) ``Principles of rSVC and its application to power systems''. Conventionally, in such control devices, the gain of the control calculation unit is constant with respect to the input, so even if the voltage of the load changes significantly due to a sudden change in the reactive power of the load, the response speed of the static reactive power control device There was a problem in that the stable operation range could not be widened for the load.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for a static reactive power control device that can eliminate the problems in the prior art described above and expand the range of stable load operation.

Overview of Irlight] 1. The stable operating range of a load becomes narrower as the impedance of the transmission line from the power supply to the load increases.

If the change in reactive power due to a change in load is AQ, and the change in load voltage due to this is AV, then lJQ and AV
There is a relationship roughly expressed by the following equation, and this is because the larger the impedance X of the power transmission line, the larger the change in AV for the same change in AQ.

A V=X −A Q ・”'
(1) In order to widen the stable operation range of the load against voltage fluctuations, AV relative to AQ may be reduced.

In other words, the static reactive power control device provides high-speed 17! If IQ can be generated, AV can be reduced to virtually zero, and the stable operation range of the load can be expanded.

For this reason, in the control device of the static type reactive power control device, the loop gain of the reactive power control device is changed according to the magnitude of AV.1. Improved the response of the reactive power control device when /IV is large.

Furthermore, even if AQ is directly detected in addition to AV as an input, and -AQ is compensated by a reactive power control device (1)
From the equation, since AV can be made substantially zero, the stable operation range of the load can be widened. In this case as well, the loop gain of the reactive power control device was changed depending on the magnitude of AQ to increase the response of the reactive power control device where AQ was large.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG. Items with the same numbers as in FIG. 2 represent the same items, so only new items will be explained. 85 is a gain adjustment circuit inserted between the arithmetic circuit 82 and the phase control circuit, in which the output has a nonlinear relationship with respect to the input, and has a nonlinear characteristic of a positive increasing function in which the larger the input, the larger the output. . Here, assuming that the gain of the arithmetic circuit 82 mentioned above is 1, the amount of reactive power compensation for the voltage deviation of the static reactive power control device can be arbitrarily changed by changing the magnitude of the output with respect to the input of this gain adjustment circuit. I can do it.

Here, the input of the gain adjustment circuit is equivalent to the input of the arithmetic circuit 82 and is the output of the adder circuit 81. That is, it is the difference (voltage deviation) between the voltage setting value V ref and the detected voltage value V of the load, and is equal to AV when the load suddenly changes.

Therefore, due to the nonlinearity of the input/output characteristics of the gain adjustment circuit, when AV is large, the amount of compensation for reactive power becomes larger than when it is zero linear.

(In other words, the loop gain becomes higher), the response becomes faster than when AV is small, and the steady state (lV=
It becomes possible to calm down to o). It is clear that the smaller the JV, the wider the stable operation range of the load against voltage fluctuations.

This gain adjustment circuit can be easily realized using an operational amplifier, a resistor, etc., and this circuit is shown in FIG.

In the figure, (a) shows the circuit, and (b) shows its input/output characteristics. In the figure, R is a resistor, OP is an operational amplifier, and D is a diode.The input/output characteristics can be changed arbitrarily by changing the fixed bias value of resistor R1, and if the circuit shown in (a) is added, the input/output characteristics can be changed even more. Output characteristics can also be obtained. A detailed explanation is given in electronic circuits, etc., so it will be omitted here.

In the above embodiment, the control calculation circuit and the gain adjustment circuit are described separately, but it is clear that the control calculation (circuit) section can also have the function of the gain adjustment circuit.

In addition, although the voltage deviation (the AC voltage difference between the voltage reference value and the actual system load) was used as the input signal, the reactive power deviation (the sum of the reactive power reference value, the actual system load, and the reactive power of the reactive power control device) was used. It is clear that the difference between In this case, the reactive power reference value and the reactive power detection value flowing through the power transmission line may be input to the adder circuit 81 in FIG.

〔Effect of the invention〕

By adding a simple circuit to the control device of a static reactive power control device, the stable operation range of the load can be expanded.

[Brief explanation of the drawing]

FIG. 1 shows a control device for a static reactive power control device of the present invention,
FIG. 2 shows a control device for a static reactive power control device according to a conventional embodiment of the present invention, and FIG. 3 shows a circuit diagram showing an example of a gain adjustment circuit of the control device of the present invention and its input/output characteristics. 4... Phase advance capacitor, 5... Step-down transformer, 6...
・・Static (′□ Positive reactive power control device, 7...
Voltage transformer, 8... Control device for static reactive power control device, 81... Addition port, 82... Arithmetic circuit, 83.
...Phase control circuit, 84...Pulse amplifier circuit.

Claims (1)

[Claims] 1. In a control device for a static reactive power control device that controls reactive power generated by controlling the current flowing through a reactor and a capacitor using a semiconductor switch, the gain changes depending on the magnitude of the input deviation signal of the control device. A control device for a static reactive power control device, characterized in that: