中文摘要：

目前对电子式互感器运行状态识别的研究开展较少，缺乏有效手段对其进行在线监测和故障诊断。通过分析电力一次系统电气量变化特点，提出了基于小波理论的电子式互感器诊断方法。通过多尺度模极大值综合处理方法定位信号的突变时刻，将处理后的各互感器信号的突变时刻进行比较，根据所提判据来区分异常信号是来自互感器自身故障，还是来自一次系统的信号突变。Matlab仿真验证了该方法能准确定位信号突变时刻，有效识别互感器的异常状态。

英文摘要：

At present, the report related to the research on recognition of operation state of electronic instrument transformers is rarely seen, it is short of effective measures for their on-line monitoring and fault diagnosis. On the basis of analyzing the variation features of electric quantities in primary system of power grid, a wavelet theory based diagnosis approach for electronic instrument transformers is proposed. By means of synthetical processing of multi-scale modulus maxima, the abrupt change moment of signal is determined and abrupt change moments of processed signals of all electronic instrument transformers are compared; then the proposed diagnostic criterion is used to distinguish whether the abnormal signal comes from its own fault of electronic instrument transformer or from the abrupt change of signal in primary system. Simulation results by Matlab verify that the proposed diagnostic criterion can accurately determine the moment when abrupt change of signal occurs and the abnormal state of electronic instrument transformers can be effectively identified.