Fuzzy expert system for metal-oxide surge arrester condition monitoring

Metal-oxide surge arresters (MOSAs) play an important role in preventing outage situations and thus in preserving the reliability of electric power system. So far, many MOSA monitoring methods have been developed. These methods propose different indicators that are more or less reliable in MOSA monitoring and diagnostics. Another important aspect of these indicators is that each one of them can be determined with a certain estimation error. None of the indicators has been proved to be supreme. Nevertheless, under different conditions, the reliability of these indicators may vary. This paper presents an analysis methodology for reliability of MOSA indicators and proposes a fuzzy logic expert system that overcomes the problem of decision-making in the case when more than one indicator is available. The analysis and verification are done by computer simulations.