Ferroresonance often occurs in power systems during system switching, which creates overvoltage situations and poses great risks to the equipment safety. In this article, a single-phase ferroresonance incident during a system energization process is presented, which occurred at a single-phase station service transformer in an ungrounded system, causing a surge arrester's failure. This incident is investigated through the PSCAD simulation and the analytical analysis. To validate the PSCAD simulation model, the relay field record is compared with the PSCAD simulation results. Several case studies are conducted using PSCAD simulation to evaluate contributing factors to this ferroresonance incident. The root cause is found to be lack of ground in the system during energization. Field practices are recommended to avoid such incidents, which were proved to be effective by successfully energizing the system in the field.

中文翻译：

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系统通电期间不接地系统中的单相铁磁谐振


电力系统在系统切换过程中经常会出现铁磁谐振，造成过电压情况，给设备安全带来极大风险。本文介绍了系统通电过程中发生的单相铁磁谐振事件，该事件发生在不接地系统中的单相站用变压器，导致避雷器失效。通过PSCAD模拟和解析分析来调查该事件。为了验证 PSCAD 仿真模型，将继电器现场记录与 PSCAD 仿真结果进行比较。使用 PSCAD 仿真进行了几个案例研究，以评估导致该铁磁谐振事件的因素。发现根本原因是通电时系统接地不足。建议进行现场实践以避免此类事件，事实证明，通过在现场成功为系统通电，这种做法是有效的。