Research on the Coordinated control Strategy of fault crossing capability of offshore wind power multi-terminal flexible DC system

Abstract

To improve the ride-through capability (RTC) of the multi-terminal offshore wind power flexible DC system in response to faults, this paper is based on the basic structure and control strategy of the voltage source converter (VSC) station of the multi-terminal offshore wind power flexible DC transmission system (MTDC), and aims at the AC grid connected to the system with three-phase short circuits and wind turbine output changes According to the situation, the mechanism of voltage drop caused by the fault is analyzed, and the DC chopper energy bleeder circuit is connected to the DC side to cooperate with the comprehensive control scheme for fault ride-through of multi-terminal offshore wind power flexible DC collection system. Through theoretical analysis and building a simulation model, the design of the control strategy of the flexible collection system and the simulation study of fault ride-through is carried out on the Shandong Peninsula Beihai Wind Farm. The results show that: the VSC station controller of the offshore wind power multi-terminal system can make the multi-terminal system wind power distribution and consumption reasonable, and realize the stable operation of the system.