Electricity and Control June 2021

TRANSFORMERS, SUBSTATIONS + CABLES

“Of the one hundred utilities we work with around the globe, NGET is one of the most focused organisations in its commitment to deliver value for consumers. The team’s technical capability and collaborative approach were critical enablers to the pace and scale of the impact these projects have achieved. Our vision at Smart Wires is a highly efficient grid that powers a cleaner planet, and we are proud to stand alongside our partners at NGET to celebrate this success.” Simon Innis, Managing Director for Omexom UK added:

“Omexom is delighted to have been selected to partner with National Grid and Smart Wires to manage and install this new technology. The strength of our teams’ relationships was integral to ensuring the success of this world first in large-scale implementation of power flow technology.” □

For more information visit: www.nationalgrid.com or www.smartwires.com

TRANSFORMERS, SUBSTATIONS + CABLES : PRODUCTS + SERVICES

Dry-type transformers customised for coal mine

Trafo Power Solutions has customised two dry-type transformers for a coal mine in South Africa’s Limpopo Province, allowing for the units to be fitted into existing enclosures and meeting the customer’s demanding duty requirements. “We would normally supply the transformer together with its enclosure, although we are also able to design the solution according to the dimensions specified as available on site,” says David Claassen, Managing Director of Trafo Power Solutions. In this case, one of the transformers – a specialised 3 900 kVA unit – had to be copper-wound to achieve a smaller footprint suitable to the space constraints, with- out compromising the technical performance. With 11 kV capacity on the primary windings, this transformer in- cluded four separate secondary windings – for 1 810 V, 1 515 V, 1 360 V and 1 210 V output respectively. “Being located outdoors on a coal mine, the trans- former had to be well protected from fine dust and mois- ture, requiring a specially designed IP54 enclosure,” says Claassen. “At the same time, the transformer’s large size meant substantial heat loss, which needed to be extracted from the enclosure. The design therefore included an air-to-air heat exchanger to recycle cool air in a closed loop.” The second transformer supplied to the mine was a 1 600 kVA unit for indoor application, stepping down from 11 kV to 550 V. Working closely with transformer repair experts Koratech Services, the company that modified the enclosure, Trafo Power Solutions was able to meet the dimensional and electrical requirements of the ap- plication – complete with control and protection system. “Underground mining often presents space con- straints which have to be considered in the design of the transformer or the miniature substation,” Claassen says. “With our expertise and our strategic partnership with leading Italy-based manufacturer TMC Transformers, we can readily cater for these conditions.” He adds that Trafo Power Solutions also supplies dry- type transformers to the marine industry, which requires transformers that can not only be safely employed in- doors, but often need to be accommodated in cramped

spaces. This experience enhances the company’s tech- nical capability in underground mines. Claassen highlights that the transformers for the coal mine were ordered during the tight Level 5 Covid-19 lockdown in South Africa. Despite similar restrictions in Italy, TMC Transformers proceeded with manufacturing, running a 24-hour, three-shift operation to ensure the re- quired social distancing. “Our high level of collaboration with our strategic part- ner enabled us to design, build and supply the transform- ers despite the Covid-19 disruption in 2020,” he says. He notes that dry-type transformers are ideal for haz- ardous and non-hazardous areas of coal mines: because oil is not used as a coolant, they are a much safer solu- tion than conventional oil-cooled transformers. They also require much less maintenance.

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

A 3 900 kVA transformer with multiple low voltage termination points.

Electricity + Control JUNE 2021

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