Theoretical and Experimental Investigation of Dual-impedance Phenomenon in Thyristor-controlled Series Capacitor

Abstract

The desired impedance of thyristor-controlled series capacitors is usually obtained by adjusting the firing angle of the thyristor. It is of great importance to make a clear relationship between the firing angle and the equivalent thyristor-controlled series capacitor impedance. This article studies the impedance characteristics of a thyristor-controlled series capacitor, considering the influence of thyristor conduction and the equivalent resistance in the reactor branch. The dual-impedance phenomenon is obtained and demonstrated by both digital simulation and a dynamic simulation experiment.

Keywords:

• thyristor-controlled series capacitor
• dual-impedance solutions
• phasor diagram
• quality factor
• thyristor conduction characteristic