Improvement of power quality by VSC based multi-terminal HVDC

Many kinds of power electronic equipments are widely applied in power system in order to improve power quality such as reducing harmonics, eliminating voltage flickers and frequency deviations. This paper proposed a total solution to power quality problem by using VSC based multi-terminal HVDC system. The controls for VSC based MTDC were designed which are composed of segments representing multi-terminal dc voltage control and current decoupled control including a dc voltage feed-forward compensation. Case studies were carried out using PSCAD/EMTDC and the results verified the effectiveness of the multi-terminal HVDC in improving power quality.