Alphamin Resources’ remote Bisie tin mine is being supplied with fit-for-purpose dry-type transformers by Johannesburg-based Trafo Power Solutions, in a fast track project that will see the complete solution manufactured in just 12 weeks.

Bisie’s location – some 160 km north-east of Goma in the Democratic Republic of Congo’s North Kivu province – places constraints on the transformers’ installation that have been taken into account in their careful selection and design.

“With a very difficult access road to the mining operation, the substation and transformers have been custom designed to withstand the many stresses expected during transport,” says Trafo Power Solutions managing director David Claassen. “To deal with the extreme heat and humidity of over 90%, we have also designed the ventilation and airflow in-house.”

The delivery will involve the movement of two 3000 kVA, 400 V / 11 kV cast resin transformers housed in six metre high cube containers. The consignment will also include the ventilation systems, lighting and small power equipment. These transformers will be used for stepping up the supply from a diesel powered generator plant – from 400 V to 11 kV – to feed the mine.

Project scope also includes two 100 kVA, 400 V / 400 V Dyn11 dry-type lighting transformers for application outdoors.

“The design of these dry-type transformers makes them suitable for the climatic conditions at the mine,” says Claassen. “They require only a minimal movement of air across the windings to cool them down, although forced air options can also be employed where necessary if ambient temperatures rise high enough.”

The higher efficiency of the cast resin design means that heat losses are lower, along with cooling requirements. This efficiency also reduces the energy consumed by these transformers, and hence will reduce diesel consumption in this application.

“An important advantage in this remote location is that dry-type transformers are almost maintenance-free and could last for 25 years without significant attention,” he says. “Oil-filled transformers require regular maintenance including oil sample analysis to ensure operational consistency and safety.”

With no oil required as a coolant, the dry-type transformer is simple, safe and installable indoors without the need for its own civils infrastructure such as bund walls and structures to ensure safety and environmental protection.

“Trafo Power Solutions works with customers to engineer technically appropriate and proven solutions for their applications,” says Claassen. “The fact that we can design and manufacture within this project’s tight deadline is further evidence of our flexibility and ability to meet demanding schedules.”