Modelling of Inspection Cycles for Power Distribution Transformers

Inspections are often carried out on power distribution assets to assess the condition of the assets so that necessary maintenance and/or replacement actions are taken to prevent failures and achieve the target reliability. Most of the inspections that are carried out on distribution assets are on a fixed time interval, often leading to a decision of "no action required". This brings a need to identify the "ideal or optimal" inspection frequency i.e. the frequency at which each inspection will give valuable information on the condition of the asset and minimize the overall inspection cost without affecting the asset reliability. This paper aims to propose an inspection scheduling model for power distribution transformers (pad-mounted type) used at EPCOR Distribution and Transmission Inc. (EDTI). The proposed model will dynamically determine the "ideal or most appropriate" next inspection schedule based on the past inspection data of pad-mounted distribution transformers. This study is highly relevant for EDTI to optimize their inspection schedules and reduce the operating costs whilst maintaining system reliability with-in acceptable and manageable risk.