提升220kV主变阻抗保护灵敏度方法的研究

Research on improving sensitivity of 220kV main transformer impedance protection

在220kV和110kV电压等级的电网的大部分故障情况下,主保护及近后备保护能满足快速切除故障的要求,对远后备保护的依赖程度有所降低.但在一些特殊情况下仍需要远后备保护动作来隔离故障,故对远后备保护的灵敏度提出了要求.当实际运行的变压器阻抗保护作为相邻线路远后备保护时,可能会因整定范围导致配合困难,而且当部分超长线路末端发生故障时,复压过流保护仍然无法满足灵敏度要求.为了满足220kV主变后备保护作为相邻出线远后备灵敏度的要求,防止发生保护误动作,需要对提高变压器阻抗保护灵敏度方法进行深入研究与分析,提出可行性的解决方案,解决部分后备保护配合困难的问题.

In the 220kV and 110kV voltage class power grids, the main protection and nearreserve protection can meet the requirements for rapid fault removal in most fault situations, and the dependence on the far reserve protection is reduced. However, in some special cases, far reserve protection action is still needed to isolate the failure, so the sensitivity of far reserve protection is required. At present, when the actual transformer impedance protection is used as the remote backup protection of adjacent lines, it may be difficult to cooperate because of the setting range. Moreover, when some ultra-long line ends fail, the over-current protection can not meet the sensitivity requirements. In order to satisfy the requirement of 220kV main change reserve protection to make the adjacent line far reserve sensitivity, prevent the occurrence of protection error action, it is necessary to conduct in-depth research and analysis on the method of improving the sensitivity of the transformer impedance protection, and propose a feasible solution to solve the problem of partial reserve protection.