Determining Distribution Substation Transformer Optimal Loadings Using a Reliability Cost-Benefit Approach

This paper presents a novel reliability cost-benefit approach, taking into account customer value of reliability, to compare different transformer loading philosophies while concurrently considering varying levels of transformer emergency capability. Using this cost benefit approach, guidelines for loading existing transformers can be determined. The developed methodology can also be used to establish standard emergency rating criteria for purchasing new transformers, which will optimize reliability´ performance versus cost. The methodology is illustrated using practical system examples