基于共模阻抗的电机主绝缘状态在线监测技术

On-line Monitoring Technology of Motor Groundwall Insulation State Based on Common Mode Impedance

在变频器工作系统中,电缆上存在高dv/dt和瞬态过电压,会导致交流变频电机绝缘老化加速。为防止意外停机和避免不可预估的经济损失,研究电机绝缘健康状态在线监测方法是非常必要的。基于共模阻抗技术对电机主绝缘的健康状态进行在线监测,在变频器电子开关频率下测量一次谐波的共模分量,利用共模阻抗计算绝缘等效电容,对主绝缘健康状态进行实时监测。为了验证该方法的有效性,搭建了实验平台,通过主绝缘热老化实验,证明该方法能够在线监测电机的健康状态,为故障预测与健康管理提供重要依据。

In the working system of frequency converters,high dv/dt and transient overvoltage on the cables can cause accelerated insulation aging of AC variable frequency motors.It is necessary to study online monitoring methods for motor insulation health status in order to prevent unexpected shutdowns and avoid unpredictable economic losses.This article is based on the common mode impedance technology for online monitoring of the health status of the groundwall of the motor.The common mode component of the first harmonic is measured at the electronic switching frequency of the frequency converter,and the equivalent capacitance of the insulation is calculated using the common mode impedance to monitor the health status of the groundwall in real-time.In order to verify the effectiveness of the method,an experimental platform was built,and through the groundwall thermal aging experiment,it was proved that the method can monitor the health status of the motor online,providing important basis for fault prediction and health management.