Vattenfall Case Study – Midel reduces risk of fire in tunnels
04/04/2002
Vattenfall has been testing a new type of transformer oil, which radically reduces the risk of fire in tunnels. The risk of fire can be eliminated using tried and tested technology in new applications.
The new transformer at the Umluspen power station in Storuman contains a type of biodegradable oil that has not previously been used in high voltage transformers of this kind (150 kV). The oil is non-inflammable and does not cause fire to spread. If the oil catches fire it will burn out extremely quickly.
- Tunnels maintain constant temperatures and atmospheric humidity, which makes them an ideal environment for transformers. However, as transformers contain approximately 30 cubic metres of oil there is always a risk of fire and additional risks in terms of explosions and personnel safety. "There have been transformer fires in tunnels abroad," explains Percy Söderqvist, engineering manager and inventor of the new transformer technology.
The new non-inflammable oil is biodegradable and leaves no toxic residues that are harmful to the environment. It has already been used in low voltage transformers and as the old transformer at Umluspen was due for replacement, Vattenfall asked for tests to be carried out to see whether the oil was also able to withstand the higher electrical stresses that would occur in this case and these tests were successful. Vattenfall subsequently ordered a new transformer that runs on this type of oil.
"We use tried and tested technology in new situations. As far as we are aware this is the first time that this has been done," Percy Söderqvist points out.
Vattenfall aims to be one of Europe's leading energy companies. Vattenfall currently produces electricity and supplies power to several million customers in Scandinavia and Northern Europe. Its biggest electricity customers are industrial and energy companies. Vattenfall's main products are electricity and heat.
