Abstract:It is easy to cause the maloperation or refusaloperation of relay protection device and result in a serious accident of power grid while modifying protection setting value without power outage.In order to control safety risk, simplify workflow, improve work efficiency and ensure the safety operation of power grid, this paper conducted a detailed danger points analysis in the work of modifying protection setting value without power outage for the line of 500kV transformer substation and proposed some preventive measures, such as unifying workflow, making investigation plan of parasitic circuit, adopting cut area operation of setting value and optimizing allocation management, etc.

Keywords:500kV transformer substation, line without power outage, protection setting value, reclosing, modify, parasitic circuit