Study on the influence of transient strong electromagnetic disturbance on acquisition unit port of electronic current transformer

The influence of transient strong electromagnetic disturbance on electronic transformer is one of the main reasons for its high failure rate, and it has become the most prominent problem faced by the development of electronic transformer technology. According to the statistics of practical fault cases and electromagnetic compatibility tests, surge, electrical fast transient burst and damped oscillatory wave are the main factors causing electromagnetic compatibility faults of electronic transformer, which are the key research content of electromagnetic disturbance suppression of electronic transformer. In this paper, an electronic current transformer product from a domestic mainstream manufacturer was selected, and the surge immunity test, electrical fast transient burstimmunity test and fast damped oscillatory wave immunity test were carried out on the product respectively through the signal and power port of the acquisition unit, which was stricter than the current national standards. The test results verify that electronic transformers have passed the electromagnetic compatibility tests stipulated by the national standards, but there are still problems in the field application, which mainly due to the more severe electromagnetic environment in the substation site. The influence rule of transient strong electromagnetic disturbance on signal and power port of acquisition unit is obtained. The distortion degree of transformer output waveform is positively correlated with the voltage level of electrical fast transient burst. The distortion period of the waveform is consistent with that of the applied electrical fast transient burst. The influence of damped oscillatory wave on transformer is strongly related to the oscillation frequency. The sensitive oscillation frequency depends on the circuit structure of the acquisition unit. The results of this paper are instructive to the electromagnetic protection measures of the acquisition unit of the electronic transformer.