Methodology for the Evaluation of the Consequence Factor of the Final Failure of Distribution Transformers

Distribution transformers set represent a significant percentage of the assets of the electric power supply system; its monitoring, forecasting and study allow the system administrator to guarantee parameters of reliability, safety and continuity in its operation. The risk assessment of an asset considers two parameters: Probability of failure and the consequences of equipment unavailability, the risk index is a widely used tool for locating investments in maintenance and repowering. This paper proposes a methodology to evaluate the consequence factor of the final unavailability of the distribution transformers considering technical characteristics, location in the network, calendar age, number of customers served and their chargeability. This information is processed through a statistical analysis to later use tools based on expert criteria, fuzzy logic and weighted sums in order to obtain the consequence index of each unit. This methodology was applied to the units to an Ecuadorian distribution company. The results obtained with the tools are consistent and provide information to the administrator about possible actions of maintenance or repowering of critical units