In this study, transients that can occur in the collection grids of offshore wind farms were investigated. On the basis of the multiple prestrike and reignition model that can reflect the actual operation of a vacuum circuit breaker (VCB), a switching transient simulation model of a typical offshore wind farm was built. The developed model included a VCB, a transformer, a cable, and an arrester. Issues concerning the closing time, length of the feeder, and topology of the collection grid were discussed. Results showed that the relationship between overvoltage amplitude and closing time was approximately sinusoidal and the maximum value was obtained when the closing time was near the peak of the power source. In addition, the overvoltage at the end of a feeder terminal was the largest among all of the transformer overvoltages of the same feeder. The overvoltage of the main transformer and that of the transformer located at the end of a feeder decreased slowly with the increase in feeder length during the closing of VCB. However, these overvoltages were positively related to feeder length during the opening of VCB. The star topology was superior to the other topologies in terms of coping with the overvoltage caused by switching transients. The effectiveness of a suppression measure, namely, installation of a resistance-capacitor filter, was also verified.

中文翻译：

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海上风电场集电网真空断路器引起的开关瞬变

在这项研究中，研究了海上风电场收集电网中可能发生的瞬变。在能够反映真空断路器（VCB）实际运行情况的多次预击复燃模型的基础上，建立了典型海上风电场的开关暂态仿真模型。开发的模型包括 VCB、变压器、电缆和避雷器。讨论了有关关闭时间、馈线长度和收集网格拓扑的问题。结果表明，过电压幅值与合闸时间的关系近似为正弦曲线，且在合闸时间接近电源峰值时达到最大值。此外，在同一馈线的所有变压器过电压中，馈线末端的过电压最大。在VCB合闸过程中，随着馈线长度的增加，主变压器和位于馈线末端的变压器过电压缓慢下降。然而，这些过电压与 VCB 开启期间的馈线长度呈正相关。在应对由开关瞬变引起的过电压方面，星形拓扑优于其他拓扑。还验证了抑制措施的有效性，即安装电阻电容滤波器。在应对由开关瞬变引起的过电压方面，星形拓扑优于其他拓扑。还验证了抑制措施的有效性，即安装电阻电容滤波器。在应对由开关瞬变引起的过电压方面，星形拓扑优于其他拓扑。还验证了抑制措施的有效性，即安装电阻电容滤波器。