| Summary: | ABSTRACT
Breakdown on air gaps with oscillatory switching surges need to be tested continuously -to get deeper knowlegdes of the phenomena and breakdown pattern of air gaps by this switching surge.
Tests with switching surges having short gaps with four wave shape of uni-directional switching surges, with frequencies of 10-khz, 20-khz, 31-khz, and 47,5-kHz were done to see the effect of those switching surges on breakdown voltages (alterations and the differences) of various air gaps. Air gaps tested were rod-rod gap, rod-sphere gap, sphere-plate gap, and plate-sphere gap, horizontally mounted, on both polarity of voltage, with gap-spacing of 17-mm and 25-mm. The shape of switching surge was previously obtained by simulation and circuit mathematical analysis. The breakdown voltage of air gap was obtained with Up & Down methode then corrected by circuit efficiency constant.
No significant effect on alteration of breakdown voltage values of testing air gaps, on both of gap-spacing, by increasing of frequency of switching surges from 10 kHz to 47,5-kHz. Breakdown voltages of rod-rod gap showed smaller values compared with sphere-plate results reaching a value of 57,17 kV. Breakdown voltages on positive polarity of rod-sphere gap were bigger than the negative ones, and those difference values were the biggest, because it field characteristic is more a-symmetrical and non-uniform. This is contradictory with the ordinary results that breakdown voltages of negative polarities have bigger values, and become patterns on sphere-plate and plate-sphere configurations.
Key words : air gaps, uni-directional oscillatory switching surges, breakdown voltages
|
|---|