Fuzzy risk assessment of MV/LV substations for maintenance and renewal purposes

Medium-voltage network operators in today´s liberalized electricity market are forced to rethink their current maintenance strategies in order to improve their companies´ efficiency. Consequently, preventive strategies such as reliability-centered or risk-based maintenance are increasingly gaining in importance, besides the traditionally implemented time-based maintenance. One principal characteristic of preventive maintenance strategies is that the condition of the network components is inspected on a regular basis. The presented methodology shows how MV/LV substation maintenance and renewal can be optimized on the basis of inspections. A fuzzy logic model processes the information gained during inspection and determines a risk index for any substation, as well as for all basic assets within the station. The model, therefore, makes the risks presented by different substations comparable. It also provides information on weak points within the substation. Thus, the model not only facilitates but also helps to objectify the decision-making for upcoming investments.