小电流接地系统铁磁谐振过电压关键影响因素辨识

Research on Key Influencing Factors of Ferroresonance Fault in Ineffective Grounding System

近年来铁磁谐振故障在小电流接地系统频繁发生,严重影响到电力设备和系统的安全运行.针对目前对铁磁谐振故障多局限于事后治理的不足,对铁磁谐振产生条件及其影响因素的作用程度进行量化对比,以确定造成铁磁谐振的关键影响因素.首先,对影响铁磁谐振故障的各因素及其作用机理进行分析,构建铁磁谐振事故树模型,确定各因素作用逻辑顺序.其次,构建灵敏度指标,量化各因素的作用程度,基于Petri网络确定关键影响因素.最后,以新疆昌吉配电网为例,对比和研究多种工况下的铁磁谐振各影响因素的作用程度.结果表明,变压器中性点参数对铁磁谐振过电压故障的影响最大,互感器中性点直流电阻的作用次之,二者均为影响铁磁谐振故障的关键因素.研究成果对预防和治理铁磁谐振过电压故障具有重要的理论参考意义.

Ferromagnetic resonance faults frequently occur in low current grounding system in recent years,which seriously affects the safe operation of power equipment and system.In view of the shortcomings that the current ferromagnetic resonance faults are mostly confined to post-treatment,the conditions of Ferromagnetic resonance and its influencing factors are quantitatively compared in order to determine the key influencing factors.Firstly,the factors affecting ferroresonance faults and their mechanism are analyzed,and the fault tree model of ferroresonance is constructed to determine the logical sequence of the factors.Secondly,the sensitivity index is constructed to quantify the extent of the factors,and the key factors are determined based on Petri network.Finally,the Changji distribution network in Xinjiang is taken as an example to study and determine the critical factors.The results show that the neutral point parameter of transformer has the greatest influence on ferroresonance overvoltage fault,and the neutral point DC resistance of transformer takes the second place.Both of them are the fundamental factors affecting ferroresonance fault.The research results have important theoretical reference for the prevention and control of ferroresonance over-voltage fault.