Utilization of rating matrices for the condition assessment of high-voltage equipment

The assessment of equipment condition is essential for the condition-based maintenance. In this paper the use of decision matrices for condition determination of high-voltage equipment is discussed. This requires a "rating" realization of the general decision matrix with adapted key rating criteria describing the equipment under examination. After forming the rating matrix, it is shown how ageing and maintenance can be integrated into the proposed approach. With the integration of ageing and maintenance the rating matrix can yield forecasts for the expected condition of the equipment in the future. The proposed method is then used in order to determine the condition of a high-voltage circuit breaker. It must be emphasized that the term "condition" used henceforth does not merely reflect the technical condition of the equipment, but it also includes economical and other aspects. It should also be noticed that, in this paper, the degradation state (rather than the actual condition state) is calculated. This approach offers specific advantages, especially when the effects of ageing or maintenance are being taken into account. Combined with a failure made, effect and criticality analysis (FMECA), the method can be used in order to calculate the risk associated with the specific piece of equipment.