Study on fault waveform library of PT high voltage side fuse in hydropower station

Abstract

In the arc-suppression coil grounding system of a medium voltage distribution network, high voltage side voltage transformer insurance fusing faults frequently occur, including fusing during startup and grid connection, fusing during operation, fusing during the shutdown, etc., which will directly affect the accuracy of measurement, metering, protection, and other secondary equipment. In this paper, we used the calculation of electromagnetic transient EMTP-ATP software, theoretical analysis of the typical hydropower station wiring and parameters of the medium voltage system, set up the improved model of neutral point grounding system, simulation of single-phase earth fault line and disappeared in the transient process, calculation of PT transient current, to verify that the way to study the mechanism of frequent fusing of fuse in the PT. Typical fault waveform databases are established under different bad working conditions (ferromagnetic resonance, low-frequency nonlinear oscillation, lightning wave invasion, etc.).