中性点不接地系统分路单相接地保护分析与改进

Analysis and Improvement of Shunt Single-phase Grounding Protection in Ungrounded Neutral System

分析了太钢十二降35 kV系统所带EAF炉、LF炉、CONARC炉、中频炉等发生接地故障时,可能引发事故扩大的原因,根据冶炼工艺、负荷变化情况,对线路单相接地故障特点进行分析,运用保护中零序电压动作特性,实施了系统接地后相继跳闸措施。该技术同样适用于同等电压、两段母线在单变压器带全部负荷时单相接地的故障切除。

This paper analyzes the possible causes of possible accident expansion when the EAF,LF,CONARC and medium frequency furnaces using the No.1235 kV transformer system of Taiyuan Steel have grounding faults.According to the condition of smelting pro?cess and load change and after analyzing the characteristics of single-phase grounding fault of the line,the zero sequence voltage action characteristics in the protection were made use of,which successfully implemented successive tripping measures after system grounding.This technology is also suitable for the removal of single-phase ground fault of the same voltage and two sections of bus under the condition of single transformer with full load.