Modeling and Analysis of Incorrect Actions of Relay Protection Systems Based on Fault Trees

The safety of the power grid is threatened by incorrect action (IA) of relay protection system (RPS) resulting from defects, and even worsen a blackout. Currently, a large amount of data about IAs and defects in RPS are accumulated in operation. However, the relationship between the IAs and device defects is unclear. Recognizing the above problems, based on the 10-year field data, this paper proposes fault tree analysis for the IAs of RPS to discover relationship between the IAs and device defects. In detail, based on analysis of the field data, the defect sets which is related to IAs are built, after that, the method to construction of two fault trees for the incorrect actions, which taking the incorrect actions as the top event, and the defect locations and component factors as the bottom level respectively, is proposed. Furthermore, combined with the 10-year filed data, the different fault trees are established and presented, and the related analysis for different responsible entities is discussed, which show the feasibility and effectiveness of proposed method.