Development and Performance Verification of a Wideband Transient Magnetic-Field Simulation Device for Substation Switching Operations

The transient magnetic field (TMF) generated by disconnector and circuit-breaker operations in substations represents a major class of electromagnetic disturbances that can compromise the reliable operation of magnetic sensors. However, laboratory methods capable of reproducing the waveform characteristics of such TMF remain limited, which restricts systematic immunity testing and quantitative evaluation of magnetic sensors. To bridge this gap, this study summarizes measured and simulated data on switching-operation transient voltages, transient currents, and TMF reported in the literature and extracts characteristic parameters related to time-domain waveform, frequency distribution, and field-strength range. Guided by these parameters, a TMF waveform reproduction method based on characteristic-parameter equivalence is proposed, and a magnetic-field immunity simulation device is developed. The device combines a rectangular coil with a cross-nested multidirectional rotating mechanism and integrates FPGA-based programmable waveform generation, high-frequency power amplification, and broadband impedance matching. This configuration enables directionally controllable 360° output of bipolar damped oscillatory magnetic fields. The test results show that the device can generate programmable bipolar damped oscillatory magnetic fields over a frequency range of 0.1–30 MHz, with an adjustable peak-to-peak magnetic-field strength reaching 800 A/m. The oscillation frequency and pulse-train parameters are programmable, while the generated magnetic field reproduces the representative damped-oscillatory characteristics of switching-operation TMF. This study provides a theoretical basis and an experimental platform for immunity testing and protective-design verification of magnetic sensors in complex high-frequency magnetic-field environments.