一种全光纤电流互感器早期故障诊断方法研究

Research on early fault diagnosis method for all optical fiber current transformers

全光纤电流互感器的一些故障在早期以测量异常的形式表现出来,本文从识别测量异常方向,提出了一种基于相位差不变原理的早期故障诊断方法。首先阐述了不变相位差原理,即在电网频率相对稳定的条件下等时间间隔截取信号,采用数值求解方法可求解出一个仅与时间间隔有关的相位差。以此相位差作为比对标准,通过分析实际相位差的变化情况,可识别全光纤电流互感器是否发生测量异常,为早期故障诊断提供辅助判据。为验证所提方法的可行性,开展了验证实验。结果表明,当全光纤电流互感器受外部干扰而发生测量异常时,本文所提的方法能识别出测量异常。以此为基础研发的全光纤电流互感器故障预警系统,已在辽宁某智能变电站投入运行。

Some faults of optical fiber current transformers will be shown in the form of phase anomaly in the early stage.From the view of abnormal measurement detection,an early fault diagnosis method of fiber optical current transformer based on the invariance principle of phase difference has been proposed in this paper.The concept of the phase difference invariance principle is first introduced,which is to intercept signals at equal time intervals under the condition of relatively stable frequency of the power grid,and a phase difference only related to the time interval can be solved by numerical analysis.By using the phase difference as the comparison standard,by analyzing the change of the actual phase difference,it can judge whether the phase measurement anomaly occurs in the electronic transformer and provides the auxiliary criterion for the early fault diagnosis.To verify the feasibility of the proposed method,a lab verification test is carried out.And the test result indicates that the proposed method can identify the measurement anomaly once the abnormal measurement occurs due to the external interferences.Based on the method,the developed fault warning system for all optical fiber current transformers has been put into operation in an intelligent substation in Liaoning Province.