Model-aided diagnosis: an inexpensive combination of model-based and case-based condition assessment

Online condition monitoring and diagnosis are being utilized more and more for increasing the reliability and availability of technical systems and to reduce their maintenance costs. Today´s model-based diagnosis (MBD) tools are able to detect and identify incipient and sudden faults very reliably. For application to cost-sensitive equipment, such as high-voltage circuit breakers (HVCBs), however, the presently available MBD systems are not feasible for economic reasons. In this paper, a novel combination of the model-based with the case-based approach to condition diagnosis is presented, which can be implemented on a low-cost computer and which offers satisfactory performance. The technique is divided into two parts: (1) preparation and (2) diagnosis. The diagnosis part can be executed on an inexpensive low-performance computer. Successful tests on real HVCBs confirm the usefulness of this new approach to condition diagnosis