Experience of Synthetic Ester Filled Transformers in SP Energy Networks

A fire in an embedded substation triggered a policy change in SP Energy Networks (SPEN) which led to the use of synthetic ester filled transformers in 11kV distribution embedded substations. Driven by improved understanding from research and increased experience in operating synthetic ester filled transformers, the use of synthetic ester then expanded to 33kV primary and 132kV grid transformers. This paper charts the increased use of synthetic ester filled transformers in SPEN along with sharing the benefits realised from adopting synthetic ester applications. Factory acceptance test and condition monitoring data are also presented which indicated the suitability of synthetic ester filled transformers as viable alternatives to conventional mineral oil filled units.