Simulation Research on Transient Overvoltage of Offshore Wind Farm Transmission System by 220kV Long-distance AC Submarine Cable

Abstract

In the offshore wind power transmission system(WPTS) through the AC submarine cable(SC), as the scale of the offshore wind farm(WF) gradually increases and the SC distance of the transmission system continues to increase, the high capacitance characteristics of the long SC will cause a large overvoltage along the SC line, which has an impact on the safe operation of offshore WFs and onshore power grids. Aiming at engineering reality, this paper builds an electromagnetic transient simulation model in PSCAD/EMTDC, and simulates and calculates the power frequency overvoltage(PFOV) along the SC line under different short-circuit capacities of the system, different active power output of offshore WFs, and different fault points. Using the MultipleRun component, this paper calculates the overvoltage along the SC for three-phase asynchronous closing and the opening overvoltage of a reignition of the circuit breaker. The research results show that the dual-terminal high-impedance configuration has a certain limiting effect on the PFOV and operating overvoltage of the submarine cable.