关于220kV变压器应用阻抗保护满足热稳定运行的分析

针对地区枢纽变220kV变压器后备保护延时普遍存在超出规程规定的变压器外部故障时热稳定允许运行时间,研究并提出220kV主变保护增加按阻抗原理特殊配置的保护方案,以达到缩短变压器后备延时满足热稳定限时需求,解决采用常规增加限速过流方案存在的与线路距离保护之间配合困难的问题。对方案进行了分析,提出变压器阻抗保护整定策略,举例表明该方案在实践中取得上下级保护相互配合的预期效果,使主设备保护满足热稳定运行需求。

Analysis of applying impedance protection to satisfy thermal stability operation for 220kV transformer

In view of the backup protection delay of regional hub 220kV transformer external fault exists beyond the allowed thermal stability running time in rules of transformer external fault.The protection scheme of 220kV main transformer protection increasing according to the special configuration of impedance principle is reaearched and proposed,in order to shorten the transformer backup delay to meet the thermal stability limit demand.solve The problems of difficultly matching with line distance protection which applies the flow scheme of conventional increasing speed limit is solved.The setting strategy of transformer impedance protection is analyzed.The example shows that the expected effect of the scheme in practice has achieved the protection coordination with each other,to meet the thermal stability requirements for the main requipment protection.