Research on Wide-band Domain Current Sensing for Bushing End Screen Based on TMR

Abstract

The transformer bushing is an important monitoring object of the substation online monitoring system. The end screen current of the transformer bushing is one of the important parameters to characterize the insulation state of the bushing, by collecting the full current of power frequency and partial discharge pulse current of the high-frequency domain. Based on the TMR array sensing principle, this paper studies the wide-band domain current sensing technology for the transformer bushing end screen current monitoring, and integrates it with the ground terminal of the bushing end screen to realize the sensing of the power frequency current and the high-frequency current of the bushing end screen. The detection bandwidth covers 50 Hz to 30 MHz. Power frequency current detection accuracy reaches 1%.