Onshore Energy Conference — London Onshore Energy Conference — London | Page 37

POWER MARKET

CONSTRUCTION DIVISiON
Mineral insulating oil

A

ppropriate risk management is
essential to placing appropriate
construction insurance, in the
power and energy sector one
of the risks exposed is the flammability
of the insulation fluids used.
Insulation fluids are used on a
large scale in electrical equipment
such as power transformers and
substations equipment.
Mineral Insulating Oil is the main
fluid used in insulation purposes. It is
a stable, biodegradable, low viscosity,
inactive oil. Mineral oil exchanges
heat easily inside equipment so is
used in electrical insulation and heat
refrigerants, without fear of the oil
attacking the equipment itself. Despite the
benefits it poses for insulation, mineral
oil is not environmentally friendly.
It has a highly soluble nature for a
hydrocarbon and its low biodegradation
rate provides it with the ability to
infiltrate rain water, contaminating
soil and surface water as a result.

EXAMPLE 1:

Every 1kg of oil spilled into a reservoir
leads to five million litres of water unfit
for consumption. Not only does this
create substantial damage to human life
and the surrounding environment, but the
remedial costs. The risk of contamination
is at its highest during the operational
stage of hydroelectric plants. These are
always situated in lakes and rivers, creating
considerable environmental risks.

EXAMPLE 2:

Each power plant transformer that
carries and utilizes oil carries an average
between 25,000- 70,000 litres as several
of these transformers are installed at each
hydroelectric plant, the risk of spillage and
contamination becomes increasingly significant.

CASE STUDY –
MINERAL OIL AND ASKAREL
Askarel is categorised as a persistent organic pollutant.
It is non-biodegradable, highly toxic, corrosive and
combustible substance. It is also carcinogenic and
mutagenic; it can therefore cause major damage to
both human life (such as irreversible damage to the
central nervous system) and the environment.
Askarel has been used as insulating oil in distribution
and generation systems, and particularly in
developing countries, cross contamination with
Mineral Oil transformers has been recorded.

This poses a significant threat. Each company
operates thousands of transformers, making it
very difficult to detect contaminated equipment
and to control the fluid exchange process.
So what can we do to limit the risk of such catastrophes?
Other oils have been suggested to replace Askarel and
other damaging mineral insulating oils, but so far no
definitive decision has been made. Other options have
been altering the containers themselves to be able to
take hold of insulating oils, reducing the fire risks.