140℃与常温条件下油纸绝缘沿面放电产气特性

Gas Generation Characteristics of Surface Discharge of Oil-paper Insulation Under 140 ℃ and Room Temperature

基于油纸绝缘柱板沿面放电模型,在实验室开展140℃与常温下油纸绝缘局部放电试验,研究油纸绝缘特征参量的变化规律,并结合Ansoft电场仿真分析高温下沿面放电机理。结果表明:在140℃下沿面放电的耗氧量与产气量均比常温下的高,而局部放电特征气体C_2H_2的含量差异不大,气体含量变化从大到小依次为H_2、C_2H_6、C_2H_4、C_2H_2、O_2、CH_4、CO、CO_2。在140℃下沿面放电发展过程中,绝缘油体积电阻率呈下降趋势,而常温下变化不明显,两种条件下油的介质损耗均呈波动上升趋势。由于高温会使高压电极与油纸交界的三角区域附着气泡,从而导致电场畸变,使得油纸绝缘的沿面放电起始电压从17.2 k V降为2.1 k V。

Based on the surface discharge model of oil-paper insulation column plate, partial discharge experiments under 140℃ and room temperature were performed in the lab, respectively, the variations of characteristic parameters of oil-paper insulation were studied and the mechanism of surface discharge under high temperature was analyzed combined with Ansoft. The results show that the oxygen consumption and gas production of the surface discharge at 140℃ are higher than those at room temperature, while the content of partial discharge characteristic gas C2H2 has little difference, the variation of gas contents from large to small is as follow： H2, C2H6, C2H,, C2H2,O2, CH4, CO, CO2. In the development process of surface discharge at 140℃, the volume resistivity of insulating oil decreases while changes little at room temperature, and the dielectric loss factors of oils increase with fluctuation under the two conditions. Because the bubbles will adhere to the triangle area between the high voltage electrode and the oil paper under high temperature, which leads to the distortion of electric field, making the surface discharge initial voltage of oil-paper insulation decrease from 17.2 kV to 2.1 kV.