Reactive power compensating apparatus capable of reducing in switching loss in steady state operation thereof.

摘要

According to the present invention, there is provided a self-commutated static var compensator for stabilizing a power system (1) by controlling an output of a self-commutated converter (3) for receiving/supplying power from/to the power system (1). A constant system voltage maintaining controller (14) calculates a first target value signal of the reactive current in accordance with a difference between a reference voltage and a voltage detected by a voltage detector (8, 11), and a reactive current controller (26) generates a second target value signal of the reactive current (3) in accordance with a difference between the first target value signal of the reactive current and a detected current. A converter controller (27) applies a gate driving pulse to the self-commutated converter (3) in response to the second target value signal of the reactive current and second target value signal of the active current. A loss reduction circuit (19) stops the gate driving pulse corresponding to the second target value of the reactive current from being supplied to the gate of the self-commutated converter (3) when reactive power output from the self-commutated converter (3) is close to zero. <IMAGE>