The comparative analysis of the partial discharge in the inter-turn insulation of transformers between constant voltage and increasing voltage

In order to research the difference of the partial discharge in the inter-turn insulation of transformers under different voltage forms, a discharge test platform is established to simulate the inter-turn discharge. By using constant AC voltage method and increasing voltage method, the partial discharge is detected by the conventional pulse current signals and the experiments are done at least five times at each voltage form. Based on the comparison and analysis of partial discharge signal, the pulse phase, cumulative discharge capacity and discharge capacity per second reflect better stable similarity in different voltage forms, however, the PD frequency, average discharge capacity and the maximum discharge capacity show relatively large difference. Conclusions of the experiments have certain guiding significance to the promotion of laboratory research results and estimation of the development of the actual transformers PD defect.