Control Strategy For VSC-HVDC And Design Of Control System Software

VSC-HVDC has been put into practice, but there are still many problems on it to be solved in theory and in practice. This thesis mainly studies VSC's translating power control, control strategy for VSC-HVDC system based on active and reactive power adjusted respectively, control strategy for VSC-HVDC system under asymmerical voltage and the design of VSC-HVDC control software based on LabVIEW. Based on the steady state model of VSC, the rectangular coordinate form of VSC's power transmitting equations is deduced through coordinate conversion. The VSC translating power control system and VSC-HVDC control system based on active and reactive power adjusted respectively are designed with inverse system nonlinear control. According to instantaneous power theory, the power characteristic of VSC under asymmerical voltage is analysed. The fluctuation of active power is eliminated with asymmetrical control scheme. At last the VSC-HVDC control software is designed with LabVIEW.