Electromagnetic Radiation Test of Molded Case Circuit Breaker During Switching Operation

The molded case circuit breaker will generate instantaneous transient overvoltage and overcurrent during the switching operation, which will induce huge electric and magnetic fields, thereby interfering with the normal operation of secondary's intelligent devices of the circuit breaker. This paper aims to analyze the electromagnetic interference generated during the switching operation of molded case circuit breakers under different voltages, currents and phases. By collecting data of the electric field strength, magnetic field strength, arc voltage, and arc current generated by different experimental groups during switching operation, time-frequency characteristics analysis of the collected waveform data were carried out to obtain the distribution of electromagnetic interference frequency bands and characteristic energy. According to experimental results, the maximum electric field generated during the arcing process is 14.27kV/m, and the maximum magnetic field is 457A/m. These results provide basis for the formulation of electromagnetic compatibility test of the primary and secondary fusion devices.