Electricity and Control June 2022

TRANSFORMERS, SUBSTATIONS + CABLES

Safety and reliability in transformers for mines

The mining sector’s focus on safety and production efficiency makes it unsurprising that mines are increasingly choosing dry-type transformer technology rather than the traditional oil-cooled options. David Claassen, Managing Director ofTrafo Power Solutions, which specialises in the design and supply of dry-type transformers, outlines some of the reasons for this.

“ T he past decades have seen the mining sector en trench a culture of zero harm, resulting in a strict approach to health and safety issues,” Claassen says. “With the current commodity boom, there is added in centive to optimise production, requiring the highest possi ble levels of reliability and performance from all equipment.” Both these imperatives are well served by the particu lar benefits of dry-type transformers, which are cooled by air and do not contain oil as a coolant. The absence of oil means dry-type transformers can be applied in a wider range of applications – and without added civils infrastruc ture – as they have a higher safety rating. Fire safety Dry-type transformers are categorised as F1 in terms of international fire resistance ratings, indicating a low level of risk. Their design and materials of construction make them self-extinguishing and flame retardant, and they will not emit harmful gases. This is important for both opencast and underground mines, especially those with designated hazardous areas where equipment is required to meet strin gent fire-safety related specifications. Additionally, with the pressure on mines to produce consistently to target, there is a growing focus on ensuring maximum uptime of operations. As well as providing higher safety levels, dry-type transformers offer high reliability and

A containerised energy solution incorporating a dry-type transformer on a mobile skid. require very little maintenance – in turn securing lower ser vice costs and less operational downtime. Mobility Trafo Power Solutions has been engaged in transformer design and installation in a variety of mining applications around Africa, ensuring that each solution meets the cus tomer’s requirements. In opencast mines, for instance, there is often a requirement for transformers to be mobile. This means they also need to be robust, to endure being moved over rough terrain on skid-mounted platforms. Working in close collaboration with leading Italy-based manufacturer, TMC Transformers, Trafo Power Solutions ensures its transformers have a rigid construction and the structural integrity to stand up well to movement and vibra tion. The absence of oil as a coolant also means there is no risk of oil leakage under these conditions. Environmental elements are another factor to be consid ered, as the transformers can be located outdoors and are designed to be protected from dust and moisture. The solu tion usually includes high levels of ingress protection – at level IP54 or IP44 – to maintain performance and longevity. Constrained spaces With their inherent safety advantages, dry-type transform ers can be used in many underground applications. Trafo Power Solutions has the in-house design capacity to cus tom engineer the transformer’s dimensions, weight and other factors to match the constraints presented by trans-

Three dry-type transformers in a single compact housing designed to meet the available footprint.

24 Electricity + Control JUNE 2022