Electricity and Control September 2020

TRANSFORMERS, SUBSTATIONS + CABLES : PRODUCTS + SERVICES

Mines choose dry-type transformers for safety

Underground mines across southern, central, and west Africa are recognising the safety benefits of dry-type transformers from Johannesburg-based Trafo Power Solutions. According to Managing Director David Claassen, these include collieries, where the strictest safety regulations apply with regard to fire hazards. “The high risk of fire in underground coal-mining environments has led to a high demand for dry-type transformers,” says Claassen. “Among the fire risks that coal mines face are transformer short-circuits as well as fires reaching the transformer.” He notes that dry-type transformer technology is rated Class F1 in terms of fire protection, ensuring that transformers supplied by Trafo Power Solutions are flame-retardant. “Oil-cooled transformers, on the other hand, are a fire risk due to the oil they contain to cool the windings,” he says. “The risk is heightened by the harsh operating conditions in which many transformers must function on mines.” Oil-cooled transformers also require regular mainte- nance. Oil samples must be taken at prescribed inter- vals, and these must be tested at a laboratory with the appropriate accreditation. Testing must be conducted to ensure that oil purity is within set limits, and to check

for gas levels and pressure build-up in the oil tank. “This maintenance can present challenges and add- ed costs if the equipment is located far from a source of expertise and the right

equipment,” says Claassen. “With dry-type transformers, it is really only the temperature that needs monitoring. The equipment generally requires servicing only twice a year.” These inspections take just a couple of hours. Key aspects to be checked are the physical termination con- nections – which must be tightened to the right torque – and any dust that has gathered around the core and windings must be cleaned away. Trafo Power Solutions has supplied dry-type transformers, together with ancillary power equipment such as low and medium voltage switchgear, to mines in South Africa, Mozambique, Zambia, the DRC, Ghana and Sierra Leone.

Transformers housed in high protection enclosures, rated to IP44 or NEMA 3R, at an oil and gas plant.

For more information contact Trafo Power Solutions. Visit: www.trafo.co.za

Electricity + Control SEPTEMBER 2020

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