基于重复脉冲法的变速抽蓄机组转子绕组短路故障诊断方法

Diagnosis method for rotor winding short-circuit fault of a variable speed pumped storage unit based on a repetitive surge oscillograph

变速抽蓄机组的转子侧采用特殊的三相交流绕组结构,导致其转子绕组短路故障诊断困难。为此,提出了一种基于重复脉冲法(repetitive surge oscillograph,RSO)的离线故障诊断方法。首先设计了重复脉冲法在变速抽蓄机组中的应用方案,通过在转子三相同时注入低压脉冲并检测响应曲线来判断机组故障情况。基于不同短路故障的响应特性分析,提出了转子绕组短路故障类型和故障相别的识别方法。然后,结合变分模态分解与Teager能量算子(variational mode decomposition-teager energy operator,VMD-TEO)估计注入脉冲和特征曲线的起始突变位置,并通过时间差值和实测波速确定故障位置。最后,利用指数还原故障因子衡量匝间短路故障的严重程度,以解决克服行波衰减引起的特征波形幅值重叠问题。仿真结果表明,所提方案能准确诊断变速抽蓄机组的各种转子绕组短路故障。

The rotor side of a variable speed pumped storage unit adopts a special three-phase AC winding structure,and this makes it difficult to diagnose a short-circuit fault in the rotor winding.Therefore,this paper proposes an offline diagnosis method based on the principle of the repetitive surge oscillograph(RSO).First,the application scheme of the RSO method in the VSPSU is designed.Low-voltage pulses are injected into three phases of the rotor simultaneously and the response curve is detected to determine the fault condition of the unit.Then based on the analysis of the response characteristics of different short-circuit faults,an identification method for rotor winding short-circuit fault types and faulty phases is proposed.Subsequently,the variational mode decomposition-Teager energy operator(VMD-TEO)method is used to estimate the injected pulse and characteristic curve's initial sudden change position and then the fault position is determined by the time difference and the measured wave velocity.Finally,an exponential recovery fault factor is proposed to measure the severity of inter-turn short circuit faults to overcome the problem of amplitude overlap of characteristic waveforms caused by traveling wave attenuation.The simulation results show that the scheme proposed in this paper can accurately diagnose various rotor winding short circuit faults of a variable speed pumped storage unit.