Extension of Power Flow Algorithm in STEPS for AC/DC Hybrid Power Systems with VSC-MTDC

The open-source simulation toolkit for electrical power systems (STEPS) was released in Github with power flow and dynamic simulation functions. However, voltage source converter based multi-terminal direct current (VSC-MTDC) was not supported in STEPS. In this paper, the steady-state model of VSC-MTDC is introduced with diverse control modes. Then, the AC/DC power flow algorithm with VSC-MTDC is designed with alternating iteration method. The controlled variables exceeding limits with different control modes are handled in the algorithm. Besides, a general data structure of VSC-MTDC is established based on PSS/E and realized in STEPS. Finally, Two cases with VSC-MTDC are tested to verify the feasibility and effectiveness of the designed algorithm.