摘要
小电流区特性是金属氧化物阀片(MOV)检测和监测的基础,为监测好MOV,保证电力系统安全运行,试验研究了MOV在空气、变压器油和液氮3种介质条件下主要电气特性。结合优异降噪能力的小波和经典补偿法的试验数据分析表明油中阻性电流和全电流略小于空气中的,而液氮中的则明显小于空气中的,并得出了相应MOV的U-I特性曲线。还进一步讨论了变压器油、液氮相对于空气对MOV主要电气性能的影响及其机理。试验结论说明液氮对MOV微观肖特基势垒的作用,即宏观体现出来的电压负温度系数性质,明显强于变压器油对MOV的渗透作用,有利于MOV防老化和延长寿命。
The media in metal oxide varistor （MOV） includes air, transformer oil and liquefied nitrogen because of the introduction of superconductor technique to power industry. In this paper, the MOV characteristic of low current region in these media is experimentally studied. By using wavelet de-noising method and compensation method, corresponding U-I curves are presented in detail. Analysis of experimental data indicates that the degree that liquefied nitrogen influences the electrical characteristic of MOV is obviously greater than that of transformer oil with regard to air. This paper also discusses the mechanism that media influence electrical characteristic of MOV. Transformer oil mainly represents limited osmosis to surface of MOV. In experimental voltage region, the effect is unconspicuous on U-I curves, and along with increase of voltage, the effect is gradually weakened by MOV characteristic. However liquefied nitrogen acts on Schottky barriers of MOV microstructure. Low temperature of liquefied nitrogen largely reduces activity of electron and ion, so the leakage current flowing through MOV falls down strongly. This reaction is called as negative temperature coefficient effect on voltage of MOV in macro-level. In experimental voltage region, the effect is more obvious on U-I curves. The effect of liquefied nitrogen is in favor of preventing ageing and extending lifetime of MOV.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2007年第5期83-86,共4页
High Voltage Engineering
关键词
MOV
泄漏电流
阻性电流
渗透作用
负温度系数性质
肖特基势垒
MOV
leakage current
resistance leakage current
osmosis
negative temperature coefficient effect
scottky barrier
