With the cage size in the shaft being one of the defining factors for this project to supply seventeen mini substations to an underground copper mine in Zambia, Trafo Power Solutions designed the mini substations so they can be easily transported to their application positions and they are equipped with effective cooling for optimal performance. The company manufactured the mini substations to order.
The mini substations designed and manufactured by Trafo Power Solutions incorporate medium- and low-voltage switchgear with dry-type transformers.
This project consolidates Trafo Power Solutions’ track record in delivering customised electrical solutions for challenging environments. Managing Director, David Claassen, says the orders included 800 kVA units and 1 000 kVA units. The project called for precise engineering to address tight space limitations and operational demands, ensuring the equipment could be transported, installed and operated reliably within confined underground spaces.
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. An essential consideration in the designs was therefore to ensure there was still sufficient airflow to cool the transformers. As the designer reduces the dimensions of the equipment, the airflow generally becomes more restricted, Claassen explains.
“Trafo Power Solutions has many years of experience in technical design to ensure the optimal performance of enclosed dry-type transformers under a wide range of environmental conditions,” he says. “We were 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 adds that, in applications like this, the mini substations need to be moved from one underground location to another – as required by the advancing of the mining face. With their dimensions designed to purpose, the mini substations can be readily loaded onto rail cars and relocated.
“Dry-type transformers offer a 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 an important role in supporting our customers there,” Claassen says. “We work closely together on projects like this one, on supply and aftersales support.”
For more information visit: www.trafo.co.za
