Failure analysis of relay protection in digital substation based on fault tree

Fault tree is modeled for relay protection in digital substation in this paper, fault tree analysis is focused on the description of a variety of possible causes and combinations of system failure, which limits to dynamic description and analysis of fault propagation, at the same time, coloring fuzzy Petri nets is introduced to dynamically describe and analyze the system´s structural characteristics and behavior, to classify, simplify the system fault tree model, thereby reducing the size of the fault tree, making the factors spread relationship clearer. FCPN model inference algorithm technology is also used for digital substation protection system failure analysis, confidence value of the component factors is obtained to help determine the main factors.