Relationship between various measurement techniques for void discharges

The paper examines three insulation-measurement techniques, individual discharge measurements, conventional power frequency bridge techniques and the charge-transfer oscillogram; and shows the theoretical link between the results of each. The theoretical predictions are confirmed by experimental results on an artificial void model. This model demonstrates that, for a given voltage above discharge inception, two discharge states are possible. In practice, the void oscillates between the two states and noninteger values of average number of discharge per cycle are produced. A linear relationship between average number of discharges and voltage is observed. Consideration is given to the form of charge-transfer oscillograms, and the conductance and capacitance voltage curves, implied by an idealised trace growing in the specified manner, are given.