Step-up containerised transformer

Louise Davis

Crestchic has secured a fifth order from NOV Portable Power for a 4.0 MVA step-up containerised transformer to support a series of offshore power installations. The end result provided NOV Portable Power with a compact, weather-proof and highly versatile transformer solution.

Based in Aberdeen, Scotland, NOV Portable Power markets and manufactures rental products that supply power to a variety of locations. It is part of National Oilwell Varco (NOV), a provider of equipment and components used in the oil and gas industry.

NOV Portable Power first approached Crestchic in 2012 to request a 2.9 MVA containerised transformer for general power rental applications. Since then, the company has placed a further four orders, with the most recent being the 4.0 MVA step-up transformer packaged in a bespoke 10ft container enclosure for offshore decommissioning purposes.

The solution needed to be flexible to accommodate various voltages and compact footprints. The 4.0 MVA multi-tap transformer provided the customer with a variety of voltages up to 14,400V and a range input voltage for the generators. This means the transformer is suitable for a variety of projects with different voltage requirements, in comparison with other options, such as a generator with a MV alternator, which would be unsuitable for this requirement as its voltage cannot be changed to match the needs of different applications.

The transformers came filled with Midel oil, which is proven to offer an environmentally friendly synthetic alternative to other fluids such as mineral oil. Midel transformer oil is a non-flammable material ensuring fire safety, which is a key requirement when operating offshore.

To provide additional safety benefits, Crestchic’s transformers are fitted with ABB class leading Safeplus medium voltage switchgear, with either low voltage Schneider Electric (formerly Merlin Gerin) master pack air circuit breakers and/or three/four pole isolators which allow individual generators to be taken in and out of service without disrupting overall power supply.

Recent Issues