Numerical Method of Switching Transient Electromagnetic Field in Substation

In order to study occurring mechanism and the distribution rule of switching transient electromagnetic field in substation, time-domain simulation model of which was constituted on the basis of finite-difference time-domain method (FDTD) in this paper. Time-dependent resistance and inductance concept of arc discharging channel were introduced, an improved time-dependent resistance of arc discharging channel was achieved by fitting the measured datum of switching transient field in typical substations. Using the improved time-dependent resistance and inductance of arc discharging channel, switching transient electromagnetic fields were simulated when the disconnecting switch operates the busbars without load and connecting line between equipment in substation. Simulated waveforms are in accordance with measured waveforms, which indicates the time-domain model is effective for investigating switching transient field, and it can be used to study electromagnetic interference in EHV and UHV substation.