Calculation and Analysis of Induced Current of Open Circuit Breaker in 500kV Substation

Abstract

The centralized distribution of a large number of power equipment in the switchyard of 500kV substations leads to complicated magnetic field distribution in the switchyard. High-voltage open circuit breakers under maintenance will generate induced currents, which is a safety hazard for circuit breaker maintenance workers. This article first measures the induced current of the circuit breaker, cable, grounding grid, and two grounding wires and the grounding switch in the 500kV switchyard of the substation, and then measures the power frequency magnetic field in the 500kV switchyard of the substation. simulation Research. The measurement and calculation results show that the peak-to-peak value of the induced current generated by the circuit breaker in the 500kV switching field in the 500kV switching field is 3.93∼7.33A, the magnetic induction intensity ranges between 0.44∼8.76µT, and the maximum power frequency magnetic field intensity is mainly concentrated Below the second bus, the closer to the normal working bus, the greater the magnetic induction intensity, which leads to the greater the induced current generated in the high-voltage open circuit breaker. When the high-voltage open circuit breaker is under maintenance, the ground wire is suspended at both ends of the circuit breaker to effectively reduce the induced voltage, thereby ensuring the safety of the operators.