一起火电厂循环水泵电动机电流波动案例分析

Analysis of current fluctuations of electric motors in thermal power plants

高压异步电动机常见的故障有转子断条裂纹及偏心,故障时定子电流表现出持续波动的特征。本文对某600MW级火电厂2B循环水泵电动机电流进行时域及频域计算与分析,确认电动机转子存在断条裂纹缺陷,并利用广义解调法对电动机电流特征分析(MCSA)结果进行验证;利用转子存在缺陷或故障时定子电流波动的特征,建立基于分布式控制系统(DCS)运行数据的异步电动机电流波动预警算法,并利用该故障电动机的历史电流数据进行验证,结果表明电动机转子断条的持续劣化能够有效地触发预警。

The common faults of high-voltage asynchronous motors include rotor bar breakage cracks and eccentricity,and the stator current exhibits continuous fluctuations.This article confirms the existence of bar breakage cracks in the motor rotor through time-domain and frequency-domain calculation and analysis of the current of a 2B circulating water pump motor in a 600MW thermal power plant.The results of motor current signature analysis(MCSA)are verified using the generalized demodulation method.By utilizing the characteristics of stator current fluctuations when there are defects or faults in the rotor,an asynchronous motor current fluctuation warning algorithm based on distributed control system(DCS)operating data is established,and the effectiveness of which is verified through the historical current data of faulty motor.It is shown that as the continuous deterioration of the rotor bar breakage can effectively trigger warnings.