A Fuzzy Petri-Net Approach for Fault Analysis Considering Factor Influences

In fault analysis or diagnosis, we not only need to assess the possibility of a fault but also need to know the impacts of various casual factors on the possible outcome of the fault. A fuzzy Petri net (FPN) has the advantage of knowledge representation and fuzzy reasoning and may become a powerful fault analysis tool. Current FPNs and reasoning algorithms, however, do not reflect the influence of the causes on the results. Based on the weighted fuzzy Petri net, an enhanced weighted fuzzy Petri net (EWFPN) as well as a reasoning algorithm is proposed in this paper. Unlike ordinary Petri nets, which use a vector to represent the markings, EWFPN uses a matrix to represent the markings and the mutual influences of the places. Through a newly developed fuzzy reasoning algorithm that is based on matrix operations, not only the markings of all the places (e.g., the possibilities of the events represented by the truth values of the places) but also the possible impacts and the effects between the factors and events can be obtained. This way, it is possible to determine the relatively important causes of the final outcomes. A gas turbine is an important piece of equipment used in many fields. The analysis of the fault of "Compressor is under turbulence", which may lead to the failure of gas turbines and cause severe consequences, is taken as an example to illustrate the proposed approach.