摘要
污秽绝缘子表面在低气压下容易出现飘弧现象,并在闪络过程中形成空气间隙电弧。绝缘子表面电弧和空气间隙电弧的U-I特性差异较大,而现有模型大多只是简单的用剩余污层表面电导率来计算表面电弧,无法准确低气压下的直流闪络特性。基于Obenaus模型,从理论上表面电弧和空气间隙电弧的差异,并利用这种差异性来作为判断直流污闪标准不同比例空气间隙电弧下的污秽度和气压指数的影响能力。结果表明:空气间隙比例不变时,污秽和气压的影响指数主要受电弧特性的影响且仅是常数,与绝缘子形状和电弧极性没有直接关系;随着空气间隙电弧比例的增加,污染影响指数会降低,但气压影响指数会逐渐增大;沿着爬电距离出现的闪络电压梯度与绝缘子的污秽程度、实际放电路径长度以及空气间隙比例和电弧极性都有关系。结论可为研究低气压下的绝缘子直流污闪特性作为参考。
Under low air pressure,DC arcs easily levitate from surface of polluted insulator to form air-gap arcs during flashover process. The U-I characteristics of surface and air-gap arcs are significantly different,so the model simply consisting of surface arc in series with residual pollution layer resistance could not accurately describe the actual DC flashover process under low air pressure. Based on Obenaus model,The antheor theoretically studied the DC pollution flashover criteria considering the different characteristics between surface arc and air-gap arc,and discussed the values of pollution and air pressure impact exponents under different proportions of air-gap arc. Study results were also compared with available experimental results. The results showed that,when the proportion of air-gap is fixed,the pollution and air pressure impact exponents are constants which are determined by arc characteristics and independent of insulator shape and arc polarity;the pollution impact exponent decreases with increase of proportion of air-gap arc,but air pressure impact exponent increase with the increase of proportion of air-gap arc;the flashover voltage gradient along creepage distance is related to pollution severity,the length of actual discharge path,and the proportion of air-gap as well as arc polarity. The conclusion can provide reference to explore the DC polluted flashover characteristics of porcelain and glass insulators under low air pressure.
作者
陈吉
蒋兴良
陈成瑞
李新梁
CHEN Ji;JIANG Xingliang;CHEN Chengrui;LI Xingliang(Engineering Department,Chongqing 400065,China;State Key Laboratory of Power Transmission Equipment&System Security and New Technology(Chongqing University),Chongqing 400044,China)
出处
《电瓷避雷器》
CAS
北大核心
2021年第1期187-193,共7页
Insulators and Surge Arresters
基金
重庆市教委科学技术研究项目(编号:KJZD-K201901901)
重庆工程学院科研基金资助项目(编号:2019gcky03)。
关键词
直流
低气压
污秽闪络
瓷和玻璃绝缘子
影响指数
DC
Low air pressure
pollution flashover
porcelain and glass insulators
impact index
