The effect of atmospheric factor on various test gaps under negative impulse voltages

This paper dealt with the effect of the atmospheric factors on various test gaps under the standard negative impulse voltage, 1.2/50 mus. The atmospheric factors in this present work were relative humidity, temperature and the ratio of the absolute humidity to the air density correction factor(h/delta). Gaps used were sphere-sphere, rod-plane and rod-rod gaps. The diameter of the sphere was 12.5 cm and the length of the rod was 20 cm. The dimensions of the plane were 4*4 cm² copper, and 70*70 cm² steel. The maximum voltage used in this present work was about 230 kV. The results of the breakdown voltage (U50) as a function of atmospheric factors were plotted. All the present data was obtained at the High Voltage Laboratory of King Mongkutpsilas University of Technology Thonburi using a 400 kV 8 kJ impulse voltage generator.