Mini substations engineered for underground mining demands

Recent orders for seventeen custom-engineered mini substations for an underground copper mine in Zambia highlight Trafo Power Solutions’ capability to deliver tailored electrical systems for complex mining environments

David Claassen, managing director of Trafo Power Solutions, confirmed that the order includes units rated at 800 kVA and 1,000 kVA. The project required precise engineering to meet strict spatial constraints and operational requirements, ensuring the substations could be transported, installed, and operated efficiently in confined underground conditions.

Each mini substation integrates medium- and low-voltage switchgear along with a transformer, forming a critical component in distributing power to underground mining equipment and infrastructure.

“The first important consideration was the size of the shaft cage used to transport equipment and material underground,” commented Claassen. “We understood what the limitations were and carefully designed a solution that would allow easy loading and transportation in the cage to the levels where the units would be deployed.”

Reducing the physical size of the substations introduced additional technical challenges, particularly around transformer cooling. Maintaining sufficient airflow within compact designs was essential to ensure reliable performance under operating conditions.

“Trafo Power Solutions has many years of experience in technical design, ensuring the optimal performance of enclosed dry-type transformers under a wide range of environmental conditions,” he said. “We were therefore careful to understand exactly what the ambient conditions would be and then to ensure that the flow of air would match the requirements of the transformers’ particular specifications.”

The design process also accounted for managing transformer losses in terms of heat and energy, ensuring effective dissipation under planned operating conditions. From a safety perspective, dry-type transformers are widely preferred in underground mining applications due to the absence of flammable liquids such as oil.

Claassen added that mobility is another important factor, as equipment often needs to be relocated as mining operations progress. The compact design allows the substations to be easily transported on rail systems within the mine.

“The dry-type transformer offers a very robust option for these demanding applications,” remarked Claassen. “There is no risk of oil leakage as a result of damage, for instance.”

All units were manufactured in South Africa within a tight production schedule, with factory acceptance testing completed successfully prior to delivery. Ongoing support will be provided through Trafo Power Solutions’ local partner in Zambia, ensuring continued reliability and aftersales service.

“Our local partner in Zambia plays a vital role in supporting our customers there,” Claassen commented. “We work closely together in projects like this one, both from a supply and aftersales support perspective.”