Radiated Magnetic Field Research of Primary–Secondary Fusion MV Switch Subjected to Ultraserious Transient Current

Abstract

With the extensive application of primary-secondary fusion Medium Voltage(MV) switch, the fault rate of acquisition circuit board of medium voltage switch increases obviously. The maintenance staff highly suspect that the electromagnetic compatibility of the MV switch has been damaged due to the short-range radiation interference. However, this kind of new switch is not equipped with electromagnetic field sensor to record the signal in real time. To solve this problem, firstly, electromagnetic interference signals under two kinds of ultra-serious current conditions (lightning current and inrush current) were found and obtained by originality test in this paper. Then, the finite integral time domain (FITD) method was introduced into the primary- secondary fusion switch, and the radiated magnetic fields of two kinds of transient currents are obtained. Finally, the radiated magnetic field near the secondary equipment were calculated and analyzed, and the research results have reference value for the resist of radiated magnetic field and the formulation of EMC standards of MV switch. The obtained radiated magnetic field can cause the sensitive equipment to malfunction.