不同波形参数冲击电压下油-隔板绝缘放电特性  

Discharge Characteristics of Oil-pressboard Insulation Under Impulse Voltage Waveforms with Different Parameters

作　　者：王喆[1] 张乔根[1] 王同磊 李金忠[2] 

机构地区：[1]西安交通大学电气工程学院,西安710049 [2]中国电力科学研究院,北京100192

出　　处：《高电压技术》2015年第6期1974-1980,共7页High Voltage Engineering

基　　金：国家电网公司重大科技项目(编号略)~~

摘　　要：变电站布置、绕组内部谐振等因素会使得侵入变压器内部的雷电过电压的波形参数异于标准波形;此外,GIS中隔离开关操作造成的特快速暂态过电压(VFTO)带来的危害也与日俱增。为此设计了一种油-隔板绝缘模型,研究了波前时间、振荡频率对击穿特性的影响,以及VFTO下油-隔板绝缘模型击穿特性和隔板几何位置对放电特性的影响。结果表明,油-隔板绝缘模型击穿电压随波前时间的减小而增高;振荡频率增大会提高模型击穿电压,最高提高达30%;油-隔板绝缘模型在VFTO下的击穿电压较标准雷电冲击电压下提高10%;单层隔板时模型击穿电压随纸板与球电极之间距离的增大逐渐降低。Due to the arrangement of the substations and the inner resonance of windings, transformers in field will en- counter lightning overvoltage with waveforms quite different from that of the standard lightning impulse. Moreover, very fast transient overvoltage （VFTO） caused by the switching operations of disconnectors in gas insulated stwichgears （GISs） brings increasing threat to transformers. Therefore, we established an oil-pressboard insulation model to simulate the typ- ical insulation configuration of transformer windings, and used it to experimentally studied the influences of impulse voltage＇s front time and oscillation frequency on the typical insulation＇s breakdown characteristics, as well as the break- down characteristics under VFTO and the influences on them from the pressboard＇s placement. It is obtained that the breakdown voltage increases either with the decrease of front time or the increase of oscillation frequency, and it can be up to 30% higher than that under standard lightning impulses. The breakdown voltage under VFTO is 10% higher than that that under standard lightning impulses. For the model with a single pressboard, its breakdown voltage decreases with increasing the distance from the sphere electrode to the pressboard.

关 键 词：特快速暂态过电压 油纸绝缘 击穿特性 振荡频率 波前时间 放电痕迹 

分 类 号：TM855[电气工程—高电压与绝缘技术]