Research On HVDC Control System Simulation

High Voltage Direct Current (abbr.HVDC) transmission system is developed rapidly in the world for its large capacity and long distance of power transmission, low cost and wastage of transmission lines, flexible and fast control mode. As the main form of interregional interconnection of power grids, steady and safe operation of HVDC transmission system is significant to industrial production and social life. Converter firing control (abbr.CFC) and tap change control of converter transformers (abbr.TCC) are core parts of HVDC control system which plays crucial role in keeping stabilization of HVDC transmission system. Normal operation and rapid recovery after faults of HVDC transmission are ensured by CFC and TCC through controlling key converter devices, therefore it is important to research on CFC and TCC for guaranteeing stabilization and reliable of HVDC transmission system.HVDC primary system simulation model was built based on AC/DC gird simulator and PSCAD/EMTDC. CFC and TCC simulation models were set up based on primary system simulation model and principle of HVDC control system, by analyzing control mode and basic components of CFC and TCC which are key parts of HVDC control system. Simulation of normal operation, transient faults and steady state changes of HVDC transmission were made to test the accuracy of HVDC primary system and control system simulation models built in this thesis.It is proved that HVDC primary system simulation model is consistent to real operating system, CFC simulation model realize the control transient faults fast. In addition, TCC simulation model has good control effect on steady state changes according to simulation results. HVDC primary system and control system simulation models built in this thesis can improve performance of control system for certifying safe and stable operation of HVDC transmission system.