Monte Carlo Simulation to Assess the Optimum Number of Distribution Spare Transformers

This paper presents a new methodology for determining the optimal number of spare transformers (pole-mounted type) to be stored in regional centers of distribution companies, in order to balance reliability and cost criteria. The proposed method is based on chronological Monte Carlo simulation to evaluate reliability indices like probability, frequency and duration of failures in distribution systems with spare components. Moreover, the model allows the calculation of annual costs associated with investment, replacement of the failed equipments, non-revenue and interruption of energy. An optimization procedure is used to determine the number of spare transformers that minimizes the expected total cost, considering all chronological characteristics. Several numerical applications and sensitivity analysis are carried out, considering actual systems data. The obtained results are thoroughly discussed.