Analysis of Protective Relay Allocation and Operation in 220 kV and Above AC Systems

This paper provides a comprehensive summary of the scale, allocation and operation situation of relay protection equipment of the 220 kV and above AC systems run by the State Grid Corporation of China in 2012 and 2013. It also analyzes the changing trend of the relevant indices of relay protection during the five years from 2009 to 2013. At the same time, it analyzes in detail two typical relay malfunction events in 2012 and 2013.