水电站发电机停机时主变压器低压侧PT谐振分析及处理

Analysis and Treatment of PT Resonance at Low Voltage Side of Main Transformer during Generator Shutdown in Hydropower Station

笔者提出了一种抑制水电站发电机停机时主变压器低压侧PT谐振的处理方法,通过对枕头坝水电站停机时出现的主变低压侧PT谐振现象,进行了深入的分析,剖析谐振出现的原因,提出了二次开口三角绕组并接电阻R0或加装专用消谐装置和PT高压侧中性点经高电阻或非线性电阻R1接地的解决方案。针对枕头坝水电站现场实际情况,比较两种方案优缺点并结合1PT高压侧中性点已通过非线性电阻R1接地实际情况,确定采用2PT高压侧中性点经非线性电阻R1接地、二次开口三角绕组两端并接电阻R0和保留微机消谐装置方式。为其他电厂类似的铁磁谐振提出了建议。

The paper presents a method to suppress PT resonance at low voltage side of main transformer during generator shutdown in hydropower station.Through deep analysis on PT resonance at low-voltage side of main transformer during shutdown of Zhentouba Hydropower Station,the causes of resonance are analyzed.The solutions are proposed,that is parallel connection of secondary open delta winding to resistance R0 or installation of special resonance elimination device and PT high voltage side neutral point grounding through high resistance or nonlinear resistance R1.According to the actual situation of Zhentouba Hydropower Station,the advantages and disadvantages of the two schemes are compared.Combined with the fact that 1PT high voltage side neutral point has been grounded through nonlinear resistance R1,it is decided to adopt 2PT high voltage side neutral point grounding through nonlinear resistance R1,two ends of secondary open delta winding are connected with resistance R0 in parallel,and microcomputer resonance elimination device is reserved.Suggestions for similar Ferroresonance in other power plants are put forward.