Setting calculation of 110 kV line protection in the change of WISCO electric grid into open loop running

The ability of relay protection to adapt the variation of running of the electric power system is limited.The WISCO electric grid is changed from the original three 220 kV transformer substations running in loop mode into two independent electric networks-Metallurgy Network and Wuzha Network running in open loop mode.The change of running mode inevitably leads to the change of cooperated relation of 110 kV line protection and as the result;the setting value has to be recalculated.Taking the line protection of Metallurgy Network as an example,the setting calculation method is elaborated.The case study shows that the setting value can meet the requirements on-site and improve true action rate of relay for line protection and therefore great economic benefit can be achieved for safe production of WISCO.