Trafo powers Zambian copper mine with custom mini substations for underground operations

Trafo Power Solutions has strengthened its reputation for delivering tailored electrical infrastructure with the supply of 17 custom-designed mini substations to an underground copper mine in Zambia.

The project includes both 800 kVA and 1,000 kVA units, each engineered to meet strict spatial and operational constraints typical of underground mining environments. According to David Claassen, the design process required careful planning to ensure seamless transportation, installation, and reliable performance within confined underground spaces.

Each mini substation integrates medium and low voltage switchgear alongside 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,” Claassen says. “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.”

Designing compact units, however, introduced challenges around cooling efficiency. Reduced dimensions can restrict airflow, making it more difficult to dissipate heat generated during operation. To address this, Trafo leveraged its extensive experience in transformer design to optimise airflow and maintain performance under specific underground 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 says. “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 engineering approach accounted for transformer energy losses and heat generation, ensuring effective heat extraction under planned operating conditions. From a safety perspective, the use of dry-type transformers is particularly advantageous in underground mining, as they eliminate the risk associated with flammable liquids such as oil.

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

Mobility was another key design consideration. As mining operations progress, equipment must often be relocated to follow the advancing mining face. The compact size of the mini substations allows them to be easily transported on rail cars and repositioned underground as needed.

All units were manufactured in South Africa within a tight production schedule. Factory acceptance testing was successfully completed before shipment, ensuring compliance with project requirements and stakeholder expectations.

In line with its commitment to reliability and long-term support, Trafo Power Solutions will provide ongoing in-country assistance through its local Zambian partner.

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