A Study on Transformer Aging Evaluation Function, Mode of Insulation Inadequacy, and the Formation of a Corresponding Markov Model

There is relatively little literature on quantifying the impact of maintenance and repair on the reliability of distribution systems. The aging evaluation function aims to determine the equipment condition or the failure mode so that measurements can be matched to any aging state in the corresponding Markov model. Here, the functions recommended by references are introduced. Then, the references with data related to the aging of distribution system equipment are presented. The parameters of the Markov model, including the average time in each state, the inspection rate in each state, and the probability of transitioning from one state to another, affect reliability and maintenance costs. The inspection rate is the only parameter that can be changed to achieve high reliability with minimal cost. Therefore, this parameter can be the most significant concern in the analysis. The analysis covers two aspects: the average time to the first failure and all related costs (failure cost, maintenance and repair cost, inspection cost). Sensitivity analysis of the inspection rate for the model has been implemented using MATLAB. Simulation results are presented and discussed.