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Influence of Variable Frequency of the Applied Voltage on Cavity Partial Discharge Parameters: A Critical Review

This paper presents a critical literature review on the influence of supply voltage frequency on partial discharges activity in an air-filled cavity. A wide range of voltages and frequencies are used for different applications. For instance, very low frequencies are used to test capacitive equipment so as to save cost and power losses since it may not be technically feasible to use power frequencies (50/60Hz). In literature review; different parameters, frequency ranges, defect types and key findings has been noted. A lot of agreements and inconsistencies have been found when it comes to key findings. The only agreements found are on partial discharge inception voltage, and delay and rise times that decrease as frequency is increased. Major reasons and explanations related to frequency dependence of partial discharges in cavities have been identified as statistical time lags, surface and bulk conductivity, and surface charge decay times. Due to the inconsistencies in results, more work and modeling need to be done in understanding the theory of PD phenomena.