Modeling and simulation analysis of Hybrid Bipolar HVDC system based on LCC-HVDC and VSC-HVDC

In recent years, it's mature that the traditional Line Commutated Converter High Voltage Direct Current (LCC-HVDC) in Chinese power system. As power electronic devices become more and more sophisticated and even perfect in practical engineering applications, Voltage Source Converter based on High Voltage Direct Current (VSC-HVDC) has also been applied to modern power grids. Hybrid Bipolar HVDC system consist of LCC-HVDC and VSC-HVDC, which system can exert the advantages of the two subsystems. In this paper, some basic structures included in Hybrid Bipolar-HVDC system will be introduced firstly. Then, the main circuits of LCC and VSC and their control circuits will be analyzed separately. Then, it is analyzed that the main circuit and control circuit of the positive LCC-HVDC and the negative VSC-HVDC in PSCAD software. Finally, Hybrid Bipolar HVDC is simulated. Simulation results show that the voltage and current of AC and DC side are consistent with the specified values. System can operate stably without oscillation or imbalance.