Green transformation

EDF Energy Networks has switched on what it believes to be the world’s first purpose-built transformer filled with vegetable oil.

The transformer, which reduces the voltage from 132,000V from overhead lines to 33,000V, is based in a substation in north Luton, and plays an essential role in the transmission of electricity to homes and businesses in the town.

The Envirotemp FR3 liquid, made from edible soya beans, is being used to replace mineral oil in the transformer. About 30,000 litres of oil are needed to act as a coolant and insulator between the metal tank and the electrical equipment inside.

This is the first time that vegetable oil has been used at such a high voltage in the UK and it is the first purpose-built 132,000V transformer in the world to be energised, although there have been some mineral oil transformers that have been retrospectively filled with vegetable oil.

The liquid is an environmentally-friendly alternative to depleting mineral oils. It is made from a natural, renewable resource, is biodegradable and more fire resistant. It is also expected to extend the life of the transformer.

Paul Dyer, an EDF Energy Networks transformer specialist, said: 'We have installed it in Luton on a trial basis and will be monitoring its performance in association with the company that built it. If successful, we hope to roll out the technology to other suitable sites across our electricity distribution areas in the east of England, London and the south east.'

The transformer has been purpose-built for EDF Energy Networks by Areva T&D and the oil supplied by Cooper Power Systems.

The fluid was shipped to Felixstowe Docks from New York in one-tonne cubes and delivered to Luton by road tanker.

Demand for vegetable oil transformer coolant is only growing slowly in the UK but, as the benefits to the environment are extensive, Cooper Power Systems plans to introduce European production and the refining of locally-grown seeds - rapeseed and sunflower being the most promising candidates.

EDF Energy Networks is working with the School of Electrical and Electronic Engineering at Manchester University and Areva T&D to compare the performance of the new transformer with a second transformer filled with mineral oil. Equipment has been fitted to the transformer so that staff can remotely monitor the live performance data.