Use of Mobile Unit Substations in Redundant Customer Delivery Systems

A reliability study has been carried out recently to find out whether the use of a mobile unit substation (MUS) in redundant customer delivery systems is justified from the economic point of view when the station two companion transformers fail randomly. The transformer failures can be short or long depending on the nature of failure. The study uses a probabilistic method based on Markov models in assessing the benefit of MUS when the two transformers are not in service. The calculated benefit from the MUS is then compared with the cost of carrying the MUS to see whether the MUS is justified or not. The purpose of this paper is to describe the study assessment methodology, its assumption and the study findings.