Recent orders to supply seventeen specially engineered mini substations for an underground copper mine in Zambia reinforces Trafo Power Solution’s track record in delivering customised electrical solutions for challenging environments.

According to David Claassen, Managing Director of Trafo Power Solutions, the orders include  800 kVA units and  1,000 kVA units. The project called for precise engineering to address stringent space limitations and operational demands, ensuring the equipment could be transported, installed and operated reliably within a confined area underground.

Each mini substation – which includes medium and low voltage switchgear as well as a transformer – plays a critical role in distributing power underground to a range of 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.”

The smaller dimensions of the units, however, brought a challenge related to the cooling of the transformers. A vital consideration in these designs was to ensure that there was still sufficient airflow to cool the transformers, he explains. As the designer reduces the dimensions of the equipment, the airflow generally becomes more restricted.

“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.”

This meant designing for a certain level of transformer losses – in terms of energy and heat – which can be effectively extracted from each unit under the planned operating conditions. From a fire protection and safety perspective, the dry-type units are preferred by many underground mines due to the absence of any flammable liquid, such as oil, in the transformer.

He notes that, in applications like this, these mini substations also need to be moved from one underground location to another – as required by the advancing of the mining face. With their convenient dimensions, the mini substations can be readily loaded onto rail cars and relocated.

“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.”

The mini substations were fully manufactured in South Africa to a tight production timeframe and the factory acceptance tests were conducted to all stakeholders’ satisfaction before shipping. In line with Trafo Power Solutions commitment to reliability and quality aftersales service, the customer will also have access to in-country support for these units.

“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.”