PROJECT: Retrofilling on-site transformer | Canada

ESTER TYPE: Shell MIDEL eN 1204 natural ester (rapeseed/canola)

PURPOSE: Replace mineral oil in an on-site asset

[ OVERVIEW ]

A leading pharmaceutical company in Toronto, with global outreach and a reputation for rapid deployment of critical and affordable medicines, identified a potential environmental concern at its corporate headquarters.

A Canadian-made, on-site transformer, rated at 4500/6000kVA 27.6kV-600/347V delta-wye had been acquired in 2012 and was operating with mineral oil as its insulating fluid. The company was advised by an Ontario-based High Voltage (HV) Maintenance Contractor of some concerns about mineral oil being used in the transformer, namely:

• mineral oil’s slow rate of biodegradability
• mineral oil’s potential flammability

[ SITUATION ]

Mineral oil’s disadvantages presented the pharma company with challenges to its stance on Corporate Social Responsibility and its guiding value of making and using products with a reduced impact on the environment. Clearly, alternatives to mineral oil in the transformer needed to be explored.

The HV contractor recommended retrofilling the transformer (replacing the mineral oil) with a Shell MIDEL ester fluid, in this case Shell MIDEL eN 1204, whose base oil is readily biodegradable according to OECD 301. Made from bio-based raw materials (canola), this is a K-class fluid with a fire point of >300°C (compared to mineral oil’s fire point of 170°C). Shell MIDEL eN 1204 also provides superior cold weather performance with its pour point of -31°C, and can extend the life of the transformer by slowing the ageing rate of the solid insulation inside the transformer.

[ RESULT ]

Retrofilling the transformer ensured that in the event of the unit rupturing and leaking insulating fluid, clean-up costs would be reduced, as the ester base oil is readily biodegradable according to OECD 301, and there would be no risk of a pool fire (due to ester fluid’s low calorific value) – a risk substantially increased with the use of mineral oil as a transformer fluid.

When performed by an experienced service company, following specific guidelines provided by the Shell MIDEL technical team, retrofilling is a safe and straightforward process. Replacing the transformer fluids takes place on-site and requires only a brief shutdown of the unit, minimizing any disruption to business and operations.

Shell MIDEL ester transformer fluids have been used in the retrofilling of distribution transformers since the 1970s. They offer a proven solution for transformer owners looking to substantially improve fire safety and transformer life expectancy.

VP of Sales and Commercial Operations for Shell MIDEL Americas