摘要
通过深度分析中性点经小电阻接地方式所存在的问题,提出了一种配电网中性点经智能电阻接地方式。与小电阻接地方式相比,智能电阻采用分区法,根据中性点电压大小将故障类型分为高阻、中阻以及低阻3个区域。在低阻故障时,能够快速选线跳闸;在中阻故障时,经过延时判断,避免对瞬时性故障的误判;在高阻故障时,启动中、低电阻动态切换,进行准确选线。综合理论分析和仿真计算可得:智能电阻接地方式不仅拥有小电阻接地方式的优点,还能够解决小电阻接地方式中部分供电可靠性低、单相低阻接地时故障点电流过大及单相断线(高阻)接地时零序保护"失灵"等死区问题。该方式对保障电力系统正常运行和人身安全等具有重要意义。
The problem of neutral grounding through small resistance is analyzed deeply,an intelligent resistance grounding mode for distribution network neutral point is put forward. Compared with the small resistance grounding method,the smart resistor adopts the subarea method. According to the neutral point voltage,the fault types can be divided into three zones: high impedance,medium resistance and low resistance. Fast line selection tripping in low resistance fault; in resistance fault,after the delay of transient fault judgment,to avoid miscarriage of justice; in the high resistance fault,starting,low resistance dynamic switching,accurate line selection. Through theoretical analysis and simulation calculation can be obtained: intelligent resistance grounding mode not only has the advantages of small resistance grounding mode,also can solve the small resistance grounding mode in low power supply reliability and low phase grounding fault current is too large and single-phase disconnection(high resistance) ground zero sequence protection " failure" the dead time problem. This method has important significance in ensuring the normal operation of power system and personal safety.
引文
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