CONTROL STRATEGY FOR VSC-HVDC SYSTEM UNDER UNSYMMETRY OF THREE PHASE VOLTAGE
LI Jin-feng,LI Guang-kai,ZHAO Cheng-yong,LI Geng-yin (Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control of Ministry of Education (North China Electric Power University),Baoding 071003,Hebei Provinece,China)
The transmitted power of Voltage Source Converter (VSC) will fluctuate under unsymmetry of three phase voltage,which affects the operation of VSC-HVDC system. According to the theory of instantaneous power, the relational expression of the relation between positive sequence voltage and negative sequence voltage, which should be satisfied in order to eliminate the transmitted power of VSC, is deduced. The power transmission equation of VSC is simplified by coordinate transformation, and the control system for transmitted power of VSC is designed by use of unsymmetrical triggering method. Simulation shows that under unsymmetry of three phase voltage the designed control system possesses good control result, the fluctuation of active power is effectively eliminated and the individual regulation of active and reactive power is realized.
【CateGory Index】： TM461