Faults Diagnosis Utilizing a Three-Layer Signed Directed Graph

Abstract

Fault diagnosis utilizing signed directed graphs is based on the analysis of fault spread patterns. Where an operator copes with an abnormal variable (e.g. too-high pressure), the cause-effect graph, which expresses the spread pattern of the fault, is cut at the variable and a new cause-effect graph is generated by the manipulation. Therefore, fault diagnosis systems utilizing single-layer signed directed graphs cannot deal with such dynamics. Fault diagnosis methods using multilayers graphs can deal with them, but they require up to hundreds of times more memory capacity than the algorithms using single-layer graphs. In this paper, a three-layer digraph is proposed to diagnose the single cause for the state shifts. This method can cope with the above situation and does not require much memory capacity.