The capacitor commutated converter (CCC) as an alternative for application in HVDC projects

Series compensated commutation is obtained by inserting a capacitor between the inverter transformer and the six pulse thyristorized Graetz bridge. This arrangement will provide a reduction in the impedance of the commutation circuit. This can permit grater efficiency of commutation, reducing the reactive power consumption of the converter and the consequent necessity of large shunt compensation banks. An improvement in the susceptibility of the converter to commutation failure is achieved, when the converter is operating in the inverter mode. In this paper, the valve commutation process as well as experimental and simulated results of current and voltage waveforms of the CCC, is studied and discussed.