Dynamic behavior of forced commutation static VAr compensator applied for reactive power compensation of HVDC converter

A conventional power converter used in an HVDC system needs line voltage to turn off the current flowing through a thyristor. Hence a HVDC system has some difficulties to operate with a weak AC system. Moreover, a HVDC system cannot supply electric power into a system which has no AC source. The recent development of high power and high frequency semiconductor devices with fast gate turn-off abilities suggests the application of a voltage source type forced commutation (VSFC) power converter to a static VAr compensator (SVC). This paper shows, by computer simulation, that the installation of VSFC-SVC can improve the performance of HVDC systems remarkably. >