JPH03210614A - Controller for 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] (Field of Industrial Application) The present invention is applicable to electric power systems! The present invention relates to a control device for a reactive power compensator that suppresses pressure fluctuations.

(Prior Art) FIG. 2 is a block diagram showing an example of a conventional reactive power compensator.

In the figure, a main circuit 3 of a reactive power compensator connected to a power system equivalently represented by an AC power supply l and a power supply impedance 2 is constructed by connecting an anti-parallel circuit of thyristors 5 and 6 in series to a reactor 4. has been done.

Further, it is common to connect a static capacitor 7 to this power system via a switching circuit 8.

On the other hand, the control circuit 9 detects the voltage of the power system using the voltage detection circuit 10.
The deviation detection circuit 1 detects the deviation between this detected value V and the voltage reference values v and f set in the reference voltage setting circuit 11.
2 is detected. On the other hand, the current from the power system is detected by the output current detection circuit 13, and this detected value is converted into a value of several percent to several tens of percent by the slope reactance circuit 14 and input to the deviation detection circuit 12. Deviation detection circuit 12
provides a deviation output obtained according to the difference between the two voltage input signals V and Vref and the current input signal (2) to a reactive power determining circuit 15 comprising an amplifier circuit, a phase compensation circuit, and the like. The reactive power determining circuit 15 supplies a reactive power signal to be compensated determined according to the voltage deviation to the thyristor firing angle control circuit 16, and sets the firing pulses of the thyristors 5 and 6 of the main circuit 3 according to the reactive power signal. Generate in phase. This ignition pulse is applied via a pulse amplifier 17 to the gates of the thyristors 5, 6.

In this configuration, when the voltage of the power system decreases, the voltage detection circuit IO detects the system voltage ■, and the deviation between this voltage V and the reference value vie is detected by the deviation detection circuit 12.

This deviation may be corrected by the output I of the output current detector 13. The output signal of the deviation detection circuit 12 is further amplified by the reactive power determining circuit 15 to become a reactive power signal, and the firing angle control circuit 16 outputs a firing pulse with a phase corresponding to this signal. This firing pulse output is amplified by a pulse amplifier 17 to fire the thyristors 5 and 6.

As a result, the delayed current flowing through the reactor 4 is reduced, and a drop in the system voltage is suppressed.

Conversely, when the grid voltage increases, thyristor 5.6
Feedback control is implemented to control the phase of the ignition pulse to increase the current flowing through the reactor 4 and to suppress the rise in system voltage.

(Problem to be Solved by the Invention) In this conventional reactive power compensator, the gain KP of the reactive power determining circuit 15 is optimized in advance according to the value of the power source impedance Z in order to stabilize and speed up the transient response of the control system. It has established. However, the value of the power source impedance 2 is not constant, and varies greatly depending on the operational status of the power system.

For example, the value of power supply impedance 2 changes due to differences between day and night, seasonal differences, and fluctuations due to expansion of power plants. Therefore, when the power supply impedance Z becomes small, the gain of the control loop decreases and the transient response becomes slow. Conversely, when the power supply impedance 2 becomes large, the gain of the control loop becomes large and the response becomes unstable, causing hunting.

The present invention solves the above-mentioned problems associated with variations in power supply impedance, and by estimating the power supply impedance and automatically adjusting the gain of the reactive power determining circuit to a value commensurate with the power supply impedance, the present invention always maintains power even when the power supply impedance changes. An object of the present invention is to provide a reactive power compensator that can obtain optimal responsiveness.

[Structure of the invention]

(Means for Solving the Problems) The present invention receives a signal to turn on or off a static capacitor installed in conjunction with a reactive power compensator in a power system, and calculates the amount of change in system voltage caused by turning on or turning off a static capacitor. , a gain adjustment means for calculating an estimated value of the power source impedance from the capacitance of the capacitor and adjusting the control gain based on this estimated value.

(Function) In the present invention, the estimated value 2 (=ΔV/ ωCv) can be calculated. By adjusting the gain of the control means in inverse proportion to this estimated value, a reactive power control device with high speed response and high stability can be realized.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, when the power supply impedance estimating circuit 18 receives a switching signal to turn on or off the capacitor 7, it estimates the power supply impedance Z from the change ΔV in the system voltage V and the capacitance C of the static capacitor by calculating 2=Δ■/ωCv. . The gain adjustment circuit 19 adjusts the gain KP of the reactive power determination circuit 15 in inverse proportion to this estimated impedance value Z.

As a result, when the estimated value Z of the source impedance becomes smaller, the transient response of the control circuit 9 becomes slower, so the gain KP of the reactive power determining circuit 15 is increased, and conversely, when the estimated value 2 of the source impedance becomes larger. is the control circuit 9
Since the transient response becomes faster and hunting occurs, the gain of the reactive power determining circuit 15 is lowered to stabilize the system.

In Fig. 1, the capacitor 7 is replaced with a reactive power compensator (TSC) that is turned off by a thyristor switch, and the impedance is determined from the system voltage when the TSC is turned on or off and the capacitance of the TSC capacitor in the same manner as in the above embodiment. It is also possible to adjust the gain.

〔Effect of the invention〕

As described above, according to the present invention, even if the power supply impedance changes depending on the operational status of the power system, the gain is automatically adjusted in the control system, making it possible to perform fast and stable reactive power control, and thereby to ensure reliability. A reactive power compensator with high performance can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a block diagram showing the configuration of a conventional reactive power compensator. 1... AC power supply, 2... Power source impedance. 3... Main circuit, 4... Reactor, 5...
...Thyristor, 6...Thyristor. 7... Static capacitor, 8... Switching circuit, 9... Control circuit, lO... Voltage detection circuit. 11... Reference voltage setting circuit, 12... Deviation detection circuit, 13... Output current detection circuit. 14... Slope reactance circuit. 15... Reactive power determination circuit, 16... Firing angle control circuit, 17... Pulse amplifier. 18... Power supply impedance estimation circuit, 19... Gain adjustment circuit.

Claims (1)

[Claims] A reactive power compensator comprising a main circuit in which a reactor and an anti-parallel connected switching element are connected in series to a power system, and a means for controlling the phase of the switching element so as to maintain the voltage of the power system at a voltage reference value. Receives a signal to turn on or cut off a static capacitor installed in parallel to the device, and estimates power supply impedance from the change in system voltage determined to be due to turning on or cutting off a static capacitor and the capacity of the static capacitor that is turned on or cut off. A control device for a reactive power compensator, characterized in that the control device calculates a value and adjusts a gain of the control means based on the estimated value.