考虑两种干扰源下的MOA在线监测数学模型探讨

MOA model for on-line monitoring based on two interference sources

氧化锌避雷器MOA(MetalOxideArrester)泄漏电流在线监测受多种干扰源的影响,无法真实反映MOA的运行状况。分析了两种主要干扰源的影响,其中相间杂散电容造成泄漏电流幅值和相位的变化;电压谐波(包括间谐波)含量大小及其相角均显著影响测量结果。在此基础上建立了计及干扰源影响的MOA在线监测数学模型并进行仿真分析,反映了小电流特性中MOA的动态变化过程,对评价泄漏电流在线监测的效果有一定参考价值。

The leakage current on-line monitoring of MOA(Metal Oxide Arrester) is influenced by some interference sources,which can't reflect its operating status. Two main interference sources are analyzed,of which the interphase stray capacitance causes the variation of leakage current's amplitude and phase angle,and the content and phase of voltage harmonic affect the measuring result greatly. A mathematical model of MOA for on-line monitoring is built up,which takes the influence of interference sources into account,and the simulative analysis is carried out,which describes the dynamic process of MOA in trickle characteristic and helps to evaluate the effectivity of on-line monitoring.