Research on Robust Optimal Power Flow of VSC-MTDC AC / DC Uncertain System

For the purpose of large-scale wind power accommodation in a voltage source converter based multi-terminal high voltage direct current (VSC-MTDC) AC/DC system, this study proposed a robust optimal power flow strategy for VSC-MTDC AC/DC uncertain systems. The strategy is suitable for long timescale application while considering the uncertainty in the power production of wind farms. The optimization mathematical model was established using cassette uncertainty set, which takes economy and security metrics into account. The economically optimal decision on limit maximum conservative solutions for all uncertain sets is obtained using the Differential Evolution and Predictor-Corrector Primal-Dual Interior Point Method (DE-PCPDIPM) hybrid optimization algorithm. Wind power transmission efficiency and effectiveness in MTDC is improved by the optimization of VSC control command value and cooperative control among converter stations. The study also proposed to alleviate wind power accommodation problem effectively through coordinated optimization with AC power grid dispatching. The effectiveness of the robust optimization strategy was verified on the IEEE 14-bus system, and the effect of parameter uncertainty range on the robust optimization decision is analyzed. The results showed the improvement in economy operation of the VSC-MTDC AC/DC uncertain system.