Breakdown strength of short airgaps under oscillatory impulse voltages

This paper presents the results of studies made on the breakdown strength of short airgaps under unidirectional, cos-bidirectional and sin-bidirectional oscillatory impulse voltages. Needle-needle and needle-plane electrode configurations have been used. The effect of variation of frequency and decay rate of the oscillatory impulse voltages on the breakdown strength have been studied. The results are compared with those obtained under AC, lightning impulse and switching impulse voltages