Research On The Capacitor Commutated Converters Based On The Stability Of The Weak AC System

Firstly, this paper introduced the development situation of the capacitance commutation inverter and its application in HVDC. Secondly, based on a certain dc net project planning to construct in china, the CCC-HVDC simulation model is built using the electro-magnetic transient simulation software PSCAD/EMTDC. Research on the dynamic performance influence and stability analysis of CCC when connecting to the weak AC system.This paper emphatically discussed the influence on the project CCC because of different level of current. For different current level, the apparent extinction angle(yapp), the real extinction angle(γreal) and the phase shifting angle(μ)were compared as well as the influence of the current size on the reactive power,and the different responses between LCC-HVDC and the CCC-HVDC under the different faults. The comparison shows that the CCC converter have a higher operational stability during AC system disturbances, and are able to increase the power transfer capability when connecting to weak AC networks.