Analysis of diagnostic methods to prevent failure of critical GIS components

High voltage (H.V.) gas insulated substations (GIS) consist of different high voltage components. These components are subjected to aging and wear during their service life. Therefore failures can occur. Failures of H.V. components can have different levels of criticality to the system reliability. In this paper, GIS components which can be critical for the GIS reliability are briefly described. The proper diagnostic methods have been selected for these components and a proposal has been made to implement them into a two level on-line monitoring system. The result is an approach to two levels on-line monitoring system, low and high level monitoring system. The low level monitoring system ignites an alarm if signal exceeds the norms. The high monitoring system assesses the risk level of the measured signals. According to the estimated risk level an action has to be taken.