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Plasma Sci. Technol. ›› 2018, Vol. 20 ›› Issue (5): 054016.doi: 10.1088/2058-6272/aaa479


Characterization and comprehension of corona partial discharge in air under power frequency to very low frequency voltage

Yuanxiang ZHOU (周远翔)1, Zhongliu ZHOU (周仲柳)1, Ling ZHANG (张灵)1 , Yunxiao ZHANG (张云霄)1, Yajun MO (莫雅俊)1 and Jiantao SUN (孙建涛)2   


  1. 1 State Key Lab of Electrical Power System, Department of Electrical Engineering, Tsinghua University, Beijing 100084, People’s Republic of China 2 China Electric Power Research Institute, Beijing 100192, People’s Republic of China
  • Received:2017-10-29 Published:2017-12-28
  • Supported by:

    This work is supported by the National Key R&D Program of China (2017YFB0902704) and the Science and Technology Project of SGCC (GY71-15-048).


For the partial discharge test of electrical equipment with large capacitance, the use of low-frequency voltage instead of power frequency voltage can effectively reduce the capacity requirements of test power supply. However, the validity of PD test under low frequency voltage needs to be evaluated. In order to investigate the influence of voltage frequency on corona discharge in the air, the discharge test of the tip-plate electrode under the frequency from 50 to 0.1 Hz is carried out based on the impulse current method. The results show that some of the main features of corona under low frequency do not change. The magnitude of discharge in a positive half cycle is obviously larger than that in a negative cycle. The magnitude of discharge and interval in positive cycle are random, while that in negative cycle are regular. With the decrease of frequency, the inception voltage increases. The variation trend of maximum and average magnitude and repetition rate of the discharge in positive and negative half cycle with the variation of voltage frequency and magnitude is demonstrated, with discussion and interpretation from the aspects of space charge transportation, effective discharge time and transition of discharge modes. There is an obvious difference in the phase resolved pattern of partial discharge and characteristic parameters of discharge patterns between power and low frequency. The experimental results can be the reference for mode identification of partial discharge under low frequency tests. The trend of the measured parameters with the variation of frequency provides more information about the insulation defect than traditional measurements under a single frequency (usually 50 Hz). Also it helps to understand the mechanism of corona discharge with an explanation of the characteristics under different frequencies.

Key words: corona, partial discharge, low frequency voltage, impulse current method, statistical parameters