基于开口变压器法的交流电机定子非激励相绕组匝间短路检测研究

Inter-turn short circuit detection of unexcited phase winding of AC motor stator based on open transformer method

为了解决交流电机定子绕组中线圈绝缘损伤引起匝间短路故障无法准确、快速定位的问题,提出将检测转子绕组匝间短路的开口变压器法移植到检测交流电机定子绕组匝间短路,定子单相添加激励源,非激励相绕组设置故障点,开口变压器检测故障点所在槽,分析故障前后开口变压器绕组感应电动势的变化。首先阐述开口变压器检测定子非激励相的工作原理,分析正常和故障状态下通过开口变压器铁心漏磁通的表达式,进一步得到开口变压器绕组感应电动势表达式,获取故障变化规律。随后建立交流电机电磁仿真模型,进行仿真分析,最后用一台定子样机进行实验验证。结果表明:故障状态下,随着故障程度的加深,故障点所在槽的开口变压器感应电动势随之减小,证明了开口变压器可以作为离线检测交流电机定子非激励相绕组匝间短路故障的有效手段。

In order to solve the problem that the inter-turn short circuit fault caused by the coil insulation damage in the stator winding of the AC motor cannot be accurately and quickly located,it was proposed to transplant the open transformer method for detecting the inter-turn short circuit of the rotor winding to the detection of the inter-turn short circuit of the stator winding of the AC motor.The excitation source was added to the single phase of the stator,and the fault point was set in the non-excitation phase winding.The open transformer detecting the slot where the fault point was located,and the change of the induced electromotive force of the open transformer winding was analyzed before and after the fault.Firstly,the working principle of the open-ended transformer to detect the nonexcited phase of the stator was described.The expression of the leakage flux through the open-ended transformer core under normal and fault conditions was analyzed.The expression of the induced electromotive force of the openended transformer winding was further obtained,and the fault variation law was obtained.Then the electromagnetic simulation model of AC motor was established,and the simulation analysis was carried out.Finally,a stator prototype was used for experimental verification.The results show that under the fault state,with the deepening of the fault degree,the induced electromotive force of the open transformer in the slot where the fault point is located decreases,which proves that the open transformer can be used as an effective means to detect the inter-turn shortcircuit fault of the stator non-excitation phase winding of the AC motor offline.