1. Xinjiang Electric Power Dispatching and Communication Center, Urumqi 830011; 2. State Grid Electric Power Research Institute of Xinjiang Electric Power Company, Urumqi 830011; 3. NR-Relays Electric Co., Ltd, Nanjing 210000
Abstract：In the 220kV and 110kV voltage class power grids, the main protection and near- reserve 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.
2019, Vol. 20 
