Study On Improvement Scheme For Tianjin Binhai220kV Bus Differential And Failure Protection

Busbar, as an fundamental part of power plants and substations, is playing animportant role in power transfer and power dispatch. It is of great signification forimproving the power quality and power supply reliablity to ensure the steadyoperation of busbar.In this paper, a detailed introduction of system protection configuration andline-connection of a substation in Binhai New Area is given. By discussing the reasonand process of CT saturation, it shows how the relay actions of busbar differentialprotection is effected by CT saturation. It also covers the analysis and research of theexist issues of busbar differential protection and failure protection in Binhai New Area.Basing on the research, a series of improvments and solutions are suggested.Includingimprovement of program and protection loops,introduction of inputs and outputs ofswitches and tripping junction and how to remove failure protection low voltage andnegative sequence voltage blocking. Some of the ideas were put into practise in somesubstations. The issues are solved effectively and the solutions are widly used inTianjin area now.