高湿条件下空气间隙放电规律的试验研究

Experimental Study on Air-gap Discharge Characteristics in Heavy Humidity

湿度是影响电力系统外绝缘的一个重要因素,但国内外相关研究较少涉及到湿度较高的情况。笔者在人工气候室开展球间隙放电试验,研究湿度(尤其是高湿条件下)与间隙放电电压的关系。研究结果表明,在湿度较低(80%以下)条件下,空气间隙放电电压随相对湿度的增加而增加;而在湿度较高(80%以上)条件下,有无凝露对放电电压的影响较大,无凝露时随着相对湿度的增加放电电压略有下降,但在湿度较高且球表面出现凝露时,间隙放电电压严重降低,甚至降低到一半。笔者利用ANSYS计算了球表面有无凝露时的球间隙电场分布,结果表明,凝露畸变了原有球间隙电场,使得最大场强增大到原电场的两倍,造成间隙放电电压严重降低,与气候实验室的结论一致。

Discharge characteristics of external insulation of power system are atmospheric humidity. However, the existing researches seldom concern high humidity significantly condition. In influenced by this study, air gap discharge tests were carried out in artificial climate chamber to investigate the relation between humidity （especially high humidity） and discharge voltage. The results show that：1）the discharge voltage increases with increasing humidity when relative humidity is less than 80%; 2）when relative humidity is above 80% the discharge voltage decreases slightly with the increase of humidity in the condition without dew, while it reduces to half of normal value in the condition with dew. The electric field in the air gap was calculated by the software ANSYS, and the result indicates that dew seriously distorts the electric field, making the maximum field strength doubled and resulting in a severe reduction in discharge voltage, which is consistent with the conclusions drawn from discharge tests in the artificial climate chamber.