JPH0125302B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a reactive power compensator.

When a load with large fluctuations, such as a Shinkansen train load, is connected to an electric power system, voltage fluctuations may become a problem due to fluctuations in the active power or reactive power of the load. As a countermeasure against such voltage fluctuations,
As an example, a reactive power compensator using a thyristor as shown in FIG. 1 has been put into practical use. As shown in Fig. 2, the conventional control method for such a reactive power compensator detects the active power or reactive power of a fluctuating load, controls the compensation reactive power amount according to the magnitude, and adjusts the amount of the load. Voltage fluctuations caused by fluctuations in active power or reactive power were controlled.

That is, in FIGS. 1 and 2, numeral 1 indicates a reactive power compensator, which is composed of a reactor 101, a thyristor switch 102, a capacitor 103, and the like. 2 is a variable load. The voltage of the power system 3 is detected by a voltage transformer 4, and the current flowing through the load 2 is detected by a current transformer 5. The detected voltage and current are input to the active power/reactive power detection circuit 6, where the active power or reactive power flowing into the load 2 is detected. The output of the active power/reactive power detection circuit 6 is input to the gate phase control circuit 7, and the output thereof is input as a gate firing phase signal to the thyristor switch 102 of the reactive power compensator 1, and the active power or reactive power of the load 2 is inputted to the thyristor switch 102 of the reactive power compensator 1. The compensator 1 is controlled to flow compensation reactive power corresponding to .

This method has the advantage of fast response because it is controlled in an open loop, but it also has the advantage of providing a fast response when the variable loads 2 are scattered over several kilometers in one power system 3 as shown in Figure 3. In some _cases , it is necessary to detect the fluctuating load currents that are separated from _each other _. Since it is necessary to transmit it to the active power/reactive power detection circuit 6 using

Furthermore, if only the variable load 2 close to the reactive power compensator 1 is controlled by simply detecting the current, there is a problem that voltage fluctuations caused by other variable loads cannot be compensated for.

The present invention has been made so that voltage fluctuations can be effectively compensated for such fluctuating loads scattered at far-off points without using large-scale transmission means.

The details will be explained below.

FIG. 4 shows a control device for a reactive power compensator according to the present invention. This control device adds a new voltage control loop to the conventional reactive power control loop. In FIG. 4, 1 is a reactive power compensator,
It is composed of a reactor 101, a thyristor switch 102, a capacitor 103, and the like. 2 indicates a variable load close to the installation location of the reactive power compensator 1. In addition, 2 ₁ and 2 ₂ are the reactive power compensator 1
Indicates a fluctuating load far away from.

The voltage of the power system 3 is detected via a voltage transformer 4 installed near the installation location of the reactive power compensator 1, and the load current of a nearby load 2 is detected via a current transformer 5. Ru. These voltages and currents are input to the active power/reactive power detection circuit 6, and the active power or reactive power Q of the variable load 2 is detected. On the other hand, the power supply voltage detected via the voltage transformer 4 is input to the voltage fluctuation detection circuit 8, where the fluctuation amount ΔV of the power supply voltage is detected, and the first-order lag circuit 9
The output of the active power/reactive power detection circuit 6 is added to the output Q of the active power/reactive power detection circuit 6 by an adder 10. These combined signals are input to the gate phase control circuit 11, and the output thereof provides a gate signal to the thyristor switch 102 of the reactive power compensator 1 to control the compensated reactive power. That is, in the case of a nearby load 2, the load current can be directly detected via the current transformer 5, so the active power and reactive power of the load are detected by the active power/reactive power detection circuit 6, and the output voltage is calculated according to the detected value Q. to control the reactive power compensator 1. This results in
Voltage fluctuations caused by nearby loads 2 can be compensated by the reactive power compensator 1.

On the other hand, regarding voltage fluctuations caused by remote loads 21 and 22, the load current is not directly detected, but the voltage of the power system caused by the load fluctuations is detected via the voltage transformer 4, and the voltage fluctuation detection circuit detects the voltage from the detected voltage. 8, the voltage fluctuation component ΔV is calculated. The △V signal is input to the adder 10 via the first-order delay circuit 9, and after being added to the output Q of the active power/reactive power detection circuit, reactive power compensation is performed so that the voltage fluctuation △V of the power system becomes zero. Activate device 1. By using the control device shown in Fig. 4, the nearby fluctuating load 2
By compensating for the variable loads 2 ₁ , 2 ₂ that are located far away using a reactive power control loop that has a fast response, and using the voltage control loop for the variable loads 2 1 , 2 ₂ that are located far away. 2 ₂ can be easily and effectively compensated for. In addition, the fourth
In the figure, 9 is a first-order delay circuit, but this circuit can also be realized by a complete integration circuit, a first-order advance circuit, or a combination thereof.

As described above, according to the present invention, load current is detected for loads located near a reactive power compensator, and voltage fluctuations caused by load fluctuations are detected for remote loads, and the voltage By compensating for fluctuations, it is possible to effectively detect both remote and nearby loads, especially without using extensive transmission means to sense the current of the remote load and transmit it to the active/reactive power detection circuit. It is possible to compensate for voltage fluctuations.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of a reactive power compensator, Fig. 2 is a block diagram showing a conventional control device for a reactive power compensator, and Fig. 3 is a block diagram showing a conventional control device for a case where fluctuating loads are scattered. FIG. 4 is a block diagram showing a control device for a reactive power compensator according to an embodiment of the present invention. In the figure, 1 is a reactive power compensator, 2, _{2 1} , 2 ₂ are variable loads, 3 is a power system, and 4
is a voltage transformer, 5, _{5 1} , 5 ₂ , 5 ₃ is a current transformer,
6 is an active power/reactive power detection circuit, 8 is a voltage fluctuation detection circuit, 9 is a first-order lag circuit, 10 is an addition circuit,
11 indicates a gate phase control circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. In a control device for a reactive power compensator that is connected to an electric power system to which a plurality of loads are connected and that controls the amount of compensated reactive power according to the power of the load, the above-mentioned power near the reactive power compensator A voltage detection means for detecting the voltage of the grid, a current detection means for detecting the current of the load near the reactive power compensator, and an amount of electricity corresponding to active power or reactive power is detected from the voltage and current detected by both of the above means. an active power/reactive power detection circuit, a voltage fluctuation detection circuit that detects voltage fluctuations in the power system from the voltage detected by the voltage detection means, and a primary system transmission circuit that transmits the output of the voltage fluctuation detection circuit; A control device for a reactive power compensator, characterized in that the control amount of the reactive power compensator is determined based on the sum of the output of the reactive power detection circuit and the output of the primary transmission circuit. 2. The control device for a reactive power compensator according to claim 1, wherein the first-order system transmission circuit comprises a first-order delay circuit, a first-order lead circuit, a perfect integration circuit, or a combination thereof.