矿井供电系统单相接地故障零模特征仿真研究

Simulation research on zero-module characteristics of single-phase grounding fault in mine power supply system

针对现有基于单相接地故障特征量的选线方法实际保护效果不理想的问题,以某煤矿实际供电系统为研究对象,采用RTDS/RSCAD实时数字仿真系统搭建了矿井供电系统仿真模型,分析了中性点不接地和经消弧线圈接地2种运行方式下线路零模电流、零模电压的故障特征规律,以及不同故障位置、故障初相角、接地电阻对矿井供电系统单相接地故障下线路零模电流时域特征的影响。研究结果表明:(1)中性点运行方式对非故障线路零模电流和母线零模电压的影响可忽略不计,对故障线路零模电流的影响较大;2种运行方式下故障线路与非故障线路零模电流首半波极性相反。(2)故障位置距离母线越远,线路暂态零模电流冲击值越小;线路稳态零模电流受故障位置影响较小。(3)故障初相角越大,线路暂态零模电流冲击值越大,冲击值增长速度越小,故障线路暂态零模电流达到稳态的时间越短;故障初相角不影响线路稳态零模电流幅值,只影响其初相角。(4)接地电阻越大,线路暂态零模电流冲击值及其衰减速度、稳态零模电流幅值越小。

For poor actual protection effect of existing line selection methods based on characteristicquantity of single-phase grounding fault, a simulation model of mine power supply system was established in RTDS/RSCAD real-time digital simulation system taking an actual mine power supply system asresearch object. Fault characteristics laws of zero-module current and zero-module voltage of lines wereanalyzed under operation modes of ungrounded neutral and arc suppression coil grounded neutral.Influences of different fault location, initial phase angle of fault and grounding resistance on characteristics of zero-module current were also researched under single-phase grounding fautt of minepower supply system. The research results are as follows： Influences of neutral point operation mode on zero-module current of non-fault line and zero-module voltage of bus can be ignored, but influence on zero- module current of fautt line is greater. Polarities of the first half wave of zero-module current in fault line and non-fault line are opposite under the two operation modes.② The farther fault locatibus, the smaller impact value of transient zero-module current is. Fault location has less influence onsteady-state zero-module current.③ The larger of the initial phase angle of fault, the larger the impact value of transient zero-module current is, the slower the impact value grows, and the shorter time reaching steady-state of transient zero-module current of fault line is. The initial phase angle of fault has no influence on amplitude of steady-state zero-module current, which only affects initial phaselarger grounding resistance, the smaller impact value and its attenuation rate of transient zero-modulecurrent and amplitude of steady-state zero-module current are.