Study on Capacitor Commutated Converter applied in HVDC projects

Abstract

Some aspects on capacitor commutated converter (CCC) applied in HVDC projects are studied. Through the analysis of the simplified AC/DC interconnected system model, the steady-state performance of CCC system is achieved, which is compared with line commutated converter (LCC) system. The expression of the peak voltage across the valves is deduced, and a proper approach to select the commutated capacitor's size is given based on the expression. With single-phase short circuit simulated, the transient performances of CCC and LCC are compared and analyzed. The simulation tool is PSCAD/EMTDC, which is for electromagnetic transient simulation. The research object is Ge-Nan HVDC mono-polar transmission project.