LAUSR

Abstract This paper investigates the characteristics of reignition overvoltage of vacuum circuit breaker, and analyzes the influences of reignition overvoltage on a power collection grid in offshore wind farms. An offshore wind farm model, including an opening model of VCB, is developed based on a parameter fitting method in PSCAD/EMTDC, which is experimentally validated covering main offshore wind farm components. The established laboratory experiment setup comprises vacuum circuit breakers, cables, transformers and equivalent equipment of a wind turbine. The experiment reignition overvoltages and currents are recorded to analyze its transient behavior, contributing to understanding the occurrence mechanisms of reignition overvoltages in offshore wind farms. Moreover, a sensitivity analysis is performed to identify factors affecting reignition overvoltages based on the developed simulation model. The statistical result analysis indicates that four out of seven investigated factors (including the capacitance (stray capacitance and cable length), the rate of rise of dielectric strength and the opening phase angle of vacuum circuit breaker) have remarkable influences on reignition overvoltages of offshore wind farms.