NEURAL NETWORKS IN PROCESS FAULT-DIAGNOSIS

Fault detection and diagnosis is currently a very important problem in process automation. Both model-based methods and expert systems have been suggested to solve the problem. Pattern recognition approach has also been investigated. Recently neural networks have been advocated as a possible technique. A number of possible neural network architectures for fault diagnosis are studied. The multilayer perceptron network with a hyperbolic tangent as the nonlinear element seems best suited for the task. As a test case, a realistic heat exchanger-continuous stirred tank reactor system is studied. The system has 14 noisy measurements and 10 faults. The proposed neural network was able to learn the faults in under 3000 training cycles and then to detect and classify the faults correctly. Principal component analysis is used to illustrate the fault diagnosis problem in question.