During the induced voltage withstand and partial discharge detection test of converter transformer

it is susceptible to interference of various factors due to relatively weak partial discharge signal at early stage of defect. It is therefore necessary to understand the propagation characteristics of interference signal in order to take corresponding suppression measures. In this paper

the induced withstanding voltage test circuit of the converter transformer under symmetrical voltage application is taken as the study object

the corresponding Simulink simulation model is proposed. The mathematical relationship between the equivalent lump capacitance parameters and those of nameplate of converter transformer in the simulation model is derived on the basis of capacitive current distribution in the winding distributed capacitance. On this basis

the propagation characteristics of source side interference signal in the test circuit is studied. The study results show that the PWM carrier frequency of variable frequency power source has a big impact in detecting harmonic contents of impedance detection signal. The circuit exists obvious resonance point. The frequency of the resonance point is related to the winding inductance of the converter transformer.The study in this paper can provide reference for formulation of interference suppression measures during the induced voltage withstand and partial discharge detection test of converter transformer.