Oct 2010
Electricity Transmission
Transformer & System Reliability
Oct 2010
Apr 2014
National Grid Electricity Transmission
Paul Jarman
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Network Innovation Allowance
At present the risk and criticality approach to transformer maintenance and replacement is based on a relatively crude 3 point scale of critically and a matrix. This method may be capable of improvement if a real network model is used together with an understanding of possible interactions between failures. Generally a transformer outage is manageable, but two or more simultaneous outages on certain parts of the network could have severe consequences. Identifying these situations and the sensitivity to linked failures is important for the correct and timely replacement of the most critical units. As far as can be determined there is nothing significant published on the interaction of transformer reliability and overall system reliability, This project will address this area.

This project will deliver a methodology for assessing the maintenance and replacement strategies for transformer replacement against system reliability requirements. In particular the derivation of transformer replacement priority from asset health index and perceived system criticality can be greatly refined using a detailed knowledge of transformer failure modes (common mode, sympathetic and hidden failures). The availability of such a methodology will ensure an optimum and justifiable prioritisation of transformer replacement maintenance. 

This project will be a success if we can understand the issue of transformer & system reliability in greater detail, or provide reasons & understanding as to why this is not possible.