UK, London - Replace cast resin assets with fire safe alternatives

Midel has recently announced that they have succesfully replaced all cast-resin transformers at Heathrow airport with fluid-filled transformers containing bio - degradable insulation oil. 

Heathrow Airport is one of the world’s busiest civil aviation hubs, serving over 80 million customers every year. The safe and reliable supply of electricity is naturally a number one priority for a facility of Heathrow’s size. To help deliver the safe delivery of electricity throughout the airport, a fleet of distribution transformers are used which provide power for critical services. According to Midel, originally all these transformers were cast-resin type; over time, these transformers presented the airport’s engineers with some problems which prompted them to explore available alternative transformer types.

According to the company, the key issue was airborne contamination, in the form of fabric dust. The cast-resin transformers were located close to the baggage handling area and since the luggage was regularly moved on and off the conveyors a large amount of fabric dust was released into the air. This, combined with general dust from the movement of many staff and passengers, lead to a residue build up on the surface of the transformers. This was further complicated by the cast-resin design; the airflow over the coils and the static fields around them actually attracted dust.

The build up of dust on the transformer could potentially cause overheating and electrical issues, therefore they had to be regularly cleaned. Initially, the operator tried to reduce the maintenance burden by installing filters on the transformers so that the dust would be trapped but these quickly clogged up and needed regular maintenance to keep the air flow high. Deciding that cast-resin transformers were not a suitable option, it was discovered that fluid-filled transformers would not be affected in the same way by dust build up. Mineral oil could not be used as a transformer fluid due to its potential flammability. The final choice was to deploy transformers filled with synthetic ester fluid – a fire safe, biodegradable fluid used in transformers worldwide.

Solution has been so successful that during the Terminal 5 expansion, their synthetic-ester-fluid-filled transformers were again used to help protect the airport and its passenger community.

Source: Midel