海上风电场真空断路器投入并联电抗器的过电压及防护

目前,海上风电场暂态过电压研究引起了广泛的关注。为改善现有海上风电场设备模型在高频条件下的局限性,搭建了真空断路器自定义高频合闸模型。考虑并联电抗器杂散电容的影响,建立了典型海上风电场35kV系统模型,用于分析投入并联电抗器过程中在汇流母线及风机端变压器上产生的操作过电压。大量仿真结果与试验显示,海上风电场投入并联电抗器将出现峰值、陡度均高于陆上风电场的操作过电压。针对这种过电压分析了多种保护方案,发现并联安装避雷器和阻容吸收器抑制过电压的综合效果较佳,为海上风电场的设计、关键设备的绝缘保护和日常运维等提供了参考。

Overvoltage and Its Protection of Switching Shunt Reactors by Vacuum Circuit Breakers in Offshore Wind Farms

At present, the research on transient overvoltage in offshore wind farms has aroused widespread concern. A self-defined high-frequency closing model of vacuum circuit breaker is built to improve the existing model limitations on the offshore wind farm equipments in high-frequency conditions. Meanwhile, considering the influence of the stray capacitance of the shunt reactor, a 35 kV system model for typical offshore wind farms is constructed to analyze the operating overvoltage in bus bars and wind turbine transformers in the process of switching shunt reactor. A large number of simulation results and experiments show that putting shunt reactors in offshore wind farms will cause the values of operating overvoltage with higher peak and steepness compared with those in onshore wind farms. In order to deal with the overvoltage problem, several protection schemes for the overvoltage suppression are analyzed. The protection scheme installing arrester and resistance-capacitance absorber in parallel has the best performance, which provides references for the design of offshore wind farm, insulation protection of key equipment and daily maintenance work.