JPS6321154Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The present invention is a static reactive power compensator (hereinafter referred to as "static reactive power compensator") in which a compensation capacitor and a compensation reactor are connected in parallel and the current of the compensation reactor is controlled by the firing phase of a thyristor. This is related to the fault diagnosis circuit of SVCS.

[Technical background of the invention and its problems]

In SVCS, the required thyristor firing phase is calculated by a reactive power compensation control circuit consisting of a reactive power detection circuit and a firing phase calculation circuit, and the thyristor firing phase of the compensation reactor is controlled via the thyristor firing circuit. Therefore, if there is an abnormality in the reactive power compensation control circuit, if there is no abnormality in the thyristor ignition circuit, the compensation reactor can continue to operate, but correct reactive power compensation will not be performed.

As a method for detecting a failure in a reactive power compensator, for example, there is a method of detecting voltage fluctuations in an electric power system using a flicker meter, but this method is not an effective method because it includes the following uncertain elements.

(a) Voltage fluctuations due to reactive power vary depending on the short-circuit capacity of the power system, so the cause of voltage fluctuations must be
It is difficult to determine that it is an SVCS failure.

(b) When multiple demand circuits that generate reactive power are connected to the same power system, which circuit
Unable to determine whether it is an SVCS failure.

[Purpose of invention]

The present invention aims to provide a fault diagnosis circuit for an SVCS that determines a fault in a reactive power compensation control circuit based on the fact that the firing angle of a compensation reactor thyristor does not change even though the reactive power of the load fluctuates. The purpose is

[Summary of the idea]

The present invention provides a static reactive power compensator in which a compensation capacitor and a compensation reactor are connected in parallel to a load, and the firing phase of a thyristor connected in series with the compensation reactor is controlled to compensate for the reactive power of the load. The reactive power and the firing phase of the thyristor are sampled and held at predetermined intervals to detect changes, and when the firing phase of the thyristor does not change even though the reactive power of the load has changed, this is detected as a stationary type. This is a failure detection circuit that determines that there is a failure in the reactive power compensator.

[Example of idea] An embodiment of the present invention is shown in the drawings.

In the figure, an SVCS whose main circuit is a compensation capacitor 1, a compensation reactor 2, and a thyristor 3 compensates for the reactive power of a load 4.

The reactive power Q of the load 4 is determined by the reactive power compensation control circuit 5.
It is detected by a reactive power detection circuit 51 in , and controls the firing phase α of the thyristor firing circuit 6 via a firing phase calculation circuit 52 .

If a failure occurs in the ignition phase control circuit 52 or the thyristor ignition circuit 6 and α does not change even if Q changes, this is detected by the failure detection circuit.

That is, using half-cycle timing, the value Q _o-1 at time t _{o-1 is held in the sample and hold circuit 7, and the value Q o-1} at time t o-1 is held in the comparator 8 at time t _o -1.
is compared with the value of Q Q _o at .

Similarly, every half cycle, the value α o _{-1 of α at time t o-1 is} held in the sample-and-hold circuit 9, and compared with the value α _o at time t _o in the comparator 10.

If Q _o-1 ≠Q _o , α _o-1 = α _o
If so, the AND circuit 11 detects this and generates the failure detection signal 12.

This allows SVCS failure to be detected relatively easily.

[Effect of idea]

As explained above, according to the present invention, a fault diagnosis circuit for a static var power compensator that detects a fault in an SVCS can be obtained using a relatively simple circuit.

[Brief explanation of the drawing]

The drawing is a circuit diagram showing an embodiment of the present invention. 1...Compensation capacitor, 2...Compensation reactor, 3
... Thyristor, 4... Load, 5... Reactive current compensation control circuit, 6... Thyristor firing circuit, 7, 9... Sample hold circuit, 8, 10... Comparison circuit, 12...
AND circuit, 51... Reactive power detection circuit, 52... Firing phase calculation circuit.

Claims (1)

[Scope of utility model registration request] A compensation capacitor and a compensation reactor are connected in parallel to a load, and the firing phase of a thyristor is controlled in series with the compensation reactor to compensate for the reactive power of the load. a comparator that samples and holds the reactive power of the load at predetermined intervals and detects the change; a comparator that samples and holds the reactive power of the load at predetermined intervals and detects the change; A failure diagnosis circuit for a static var power compensator, characterized by comprising an AND circuit that outputs a failure detection signal when the phase does not change.