ผลของความชื้นต่อแรงดันเบรกดาวน์กระแสสลับและอิมพัลส์รูปคลื่นฟ้าผ่า ของแกปทรงกลมมาตรฐาน / พงษ์ศักดิ์ มฤคทัต = Effect of humidity on AC and lightning impulse breakdown voltage of standard sphere gaps / Pogsak Marukatat
This thesis study the effect of humidity on breakdown voltage of 25 cm diameter standard sphere gaps, under AC and standard lightning impulse 1.2/50 mu(s) voltage at several gap distances. At small gap spacing or low breakdown voltage, humidity practically has no effect on breakdown voltage for both AC and standard lightning impulse 1.2/50 mu(s) voltage. With increasing gap spacing, impulse breakdown voltage increases with increasing humidity. At large gap distances, the positive impulse breakdown voltage is independent from humidity. However the negative impulse breakdown voltage is decreased as humidity is increased and the AC breakdown voltage is also decreased with increasing humidity. The humidity correction factor, as given in IEC 60052, for testing with standard lightning impulse 1.2/50 mu(s) at humidity range not exceeding 15 g/m[superscript 3] is still valid. For humidity above 15 g/m[superscript 3] the correction is not good enough. In the case of testing with AC voltages, the correction is invalid for the whole range of humidity. Therefore, we should applied new humidity correction factor appropriated for testing during high humidity.