Effect of Damping Resistance on On-load Tap Changer Switching Test Current

The switching test of the on-load tap changer (OLTC) is essential to assess the performance of the tap changer. At present, the resonance method is mainly used to test the switching performance of the tap changer. In order to explore the effect of the damping resistance on the switching current of the OLTC in the resonance method, this paper establishes the switching test model of the resonance method, and analyzes the switching test current under the same damping resistance, different switching processes and different damping resistances. The ATP-EMTP simulation results show that when the tap changer is switched from odd to even tap, the current distortion of the auxiliary OLTC is small; when switched from even to odd tap, the current distortion of the auxiliary OLTC is large. According to the simulation results and analysis, a method for selecting the optimal damping resistance of the switching test is proposed. The research results provide an important theoretical reference for the optimization of the OLTC switching test.