将负序电流作为异步电机定子绕组匝间短路的故障特征量,在提取时易受谐波、噪声等因素的影响,而频谱分析也较为复杂,故障诊断的可靠性和高效性难以兼顾。为可靠高效地诊断异步电机定子绕组匝间短路,在多次派克变换的基础上,提出故障特征量Izpg以反映故障。首先根据故障后的电机磁场推导出故障后定子中存在的电流频次；然后得到非理想工况下,利用多次派克变换提取故障特征量Izpg的表达式；最后建立故障后异步电机的多回路数学模型,对理想工况和非理想工况下定子不同严重程度的匝间短路进行仿真。分析结果表明,Izpg和故障严重程度正相关且对电压源不平衡这类非理想工况呈现鲁棒性,用Izpg诊断异步电机定子匝间短路具有高灵敏性与高可靠性。

When the negative sequence current is taken as the fault characteristic quantity of interturn faults in stator windings of asynchronous motor, its extraction is easily affected by harmonics and noises and the spectrum analysis is rather complicated, so it is difficult to balance the reliability and efficiency of fault diagnosis. In order to diagnose interturn faults in stator windings of asynchronous motor reliably and efficiently, on the basis of multiple Park’s transformations, the fault characteristic quantity Izpg was put forward to reflect the fault. The current frequency in the stator after the fault was deduced according to the motor magnetic field after the fault firstly. Then the expression of fault characteristic quantity Izpg extracted by multiple Park’s transformations was obtained under nonideal working conditions. Finally, the multiloop mathematical model of asynchronous motor after fault was established, and the interturn fault of stator with different severity under ideal and nonideal conditions was simulated. The analysis results showed that the Izpg was positively correlated with the severity of the fault and had robustness to nonideal conditions such as voltage source imbalance, and it was highly sensitive and reliable to diagnose the stator interturn fault of asynchronous motor by Izpg.

TM 343