Partial discharge spectral response to variations in the supply voltage frequency

Partial discharge (PD) spectral response to variations in the supply voltage frequency was experimentally investigated through laboratory-based tests. The PD spectral content of each defect type responded uniquely to variations in the sinusoidal supply voltage frequency in the range 20 to 400 Hz. The findings are interpreted using the theory of space charge dynamics in PD mechanisms. Prospective diagnostic applications of the findings include PD recognition using supply voltage frequency sweeps. Knowledge on supply voltage frequency dependency of partial discharges also helps in comparing PD diagnostic test results obtained at different test voltage frequencies.