Innovative Transformer Fluid Retrofit Yields $500k Savings

Innovative Transformer Fluid Retrofit Yields $500k Savings for Rural Australian Substation

Ergon Energy Networks, serving over 750,000 customers across more than one million square kilometres in Queensland, Australia, recently implemented a cost-effective and environmentally friendly solution at their Comet substation, located approximately 300 km west of Rockhampton. The substation's 66/22 kV, 6.3 MVA transformer, which had been operational for ten months with mineral oil as the insulating fluid, was identified for retro filling to enhance safety and reduce costs.

The engineering team selected MIDEL 7131, a synthetic ester transformer fluid, due to its superior properties:

• Fire point exceeding 300°C
• Fully and readily biodegradable
• High oxidation stability
• Excellent moisture tolerance, which protects the transformer's solid insulation and extends its lifespan

A significant advantage of using MIDEL 7131 was the ability to implement an earthen bund system that directs any potential fluid leakage into an oil separation tank. This design eliminated the need to expand the substation site for a traditional oil containment system, resulting in savings of approximately $500,000 in civil works.

Steven Lowry, Ergon Energy Networks Manager for Capricornia West, emphasised the project's success:

"We are using an earthen bund arrangement that directs the ester to an oil separation tank, and that has resulted in a saving of approximately half a million dollars on this project. This means we can realistically look at doing something similar at some of our other rural substations, and we can do it in a much more environmentally responsible and safe way that delivers value for our customers." 

This initiative not only enhanced fire safety and environmental responsibility but also demonstrated a practical approach to cost savings, aligning with Ergon Energy's commitment to delivering secure, affordable, and sustainable energy solutions to its customers.