基于偏磁消弧线圈的综合增量法单相接地保护

分析了补偿电网单相经电阻接地的现象，利用消弧线圈电感变化前后的系统零序电压和零序电流定义了零序电流综合增量概念。给出了零序电压、零序电流和综合增量的向量图及不同接地电阻下向量的变化轨迹。建立了综合增量与补偿电流变化前零序电压百分数和补偿电流变化量之间的关系，构建了零序电流综合增量法接地选线判据。介绍了基于上述原理的接地选线装置的硬件结构及软件流程。设计了带自检线圈的零序电流互感器和自检及误差矫正单元。样机经现场运行表明选线准确、可靠。

PROTECTION FOR DETECTING SINGLE-PHASE-TO-GROUND FAULT FEEDER BASED ON SYNTHESIS INCREMENT PRINCIPLE IN RESONANT GROUNDED POWER DISTRIBUTION SYSTEM WITH ARC-SUPPRESSION WITH MAGNETIC BIAS

Featured in this paper is an in depth analysis of single phase to ground fault through a resistance in resonant grounded power distribution system. With the zero sequence voltage being, the current being at the time before the arc suppression coil inductance changes, and, after it changes, the zero sequence current synthesis increment is defined, represented by . Vectors of zero sequence voltage, zero sequence current and its synthesis increment and their change tracks with different grounding resistance are shown. The relation between synthesis increment and the zero sequence voltage percent at the time before arc suppression coil current changes and the change quantity is found. The criterion based on the principle of synthesis increment for detecting grounded feeder is established. A device based on the principle mentioned above for detecting grounded feeder is developed. The black diagram of its hardware and the flow of its software are given. The zero sequence current transformer with a coil for self check up is used, and the cell used for checking up the current transformer and rectifying its error is developed. For over one year site operation, it is shown that the device based on the principle mentioned above can detect fault feeder accurately and reliably.