To accurately analyze high-frequency and high-amplitude electromagnetic inference during the operation of high-voltage switchgear, a modeling method based on a dynamic reignition arc model is proposed. The simulation effects under different arc models are compared using ATP-EMTP software, and the influence of five factors, i.e. arc resistance, line length, breakdown delay, fracture capacitance and arc inductance, on the simulation results are discussed. In addition, an experimental circuit for the disconnector to separate and connect the capacitive low current is built. By comparing the simulated and measured data, it is found that in comparison with the traditional model, the errors between the simulated and measured peak values of transient voltage and transient current are reduced by 0.64% and 13.94% respectively under the dynamic reignition arc model. The characteristic parameters of simulation waveforms are all within the variation range of the measured data. This indicates that the proposed model can reflect the transient process more accurately during the on/off operation of the disconnector. This is of great significance for improving the calculation accuracy of the transient voltage and transient current during the switching operation. This work is supported by the National Natural Science Foundation of China (No. U1866201).