选择性井下高压电网行波距离保护研究

煤矿高压电网发生短路故障常导致无选择性越级跳闸,这是井下供电长期存在的安全隐患和技术难题。文章利用小波变换模极大值与行波奇异点的对应关系,准确提取各次行波到达保护安装处的时刻,然后通过实时计算电缆中特定频率下的行波波速,对故障点进行精确定位;利用保护动作时间随故障距离增大而增大的关系,以微机的逻辑判断构建了快速、具有选择性且不受保护间联锁影响的纵向保护系统。

Research of Selcctive Distance Protection of Traveling Wave for Underground High-voltage Power Network

The breaker often took place unselective overstep tripping when short circuit fault occurred in mine high-voltage power network,which is a technical problems and potential safety hazard of underground power supply existed for a long time.The paper used the correspondent relation between modulus maximum of wavelet transform and traveling wave singularity point to measure time of arriving protection installation of traveling wave,then calculated traveling wave speed under particular frequency of the cable in real time for accurate fault location.It made use of action time of protection increasing with fault(distance) to construct a fast and selective longitudinal protection system by microcomputer's logic judgment,which is not influenced by protections' interlock.