Low loss cast resin transformers for African market

South Africa, Johannesburg: Trafo Power Solutions is recommending companies to make use of the recent improvements in the design of cast resin transformers to boost safety and energy efficiency.

Trafo Power Solutions Managing Director, David Claassen, explains how new improvements surpass traditional oil-filled transformers used in power gird systems. These high efficiency solutions include open-wound transformers (OWTs), vacuum-pressured impregnated transformers (VPIs) and cast resin transformers (CRTs).

“OWTs are constructed by dipping preheated windings into a high temperature varnish bath and then baking the high temperature varnish,” said Claassen. “This replaces the need for oil and paper, so only a small amount of material is flammable.”

Traditional oil-filled transformers use paper saturated in oil wrapped around the winding material as an insulation medium. If not maintained correctly, insulation degradation will occur, with the oil posing both a safety and environmental risk, according to Trafo.

“With CRTs, windings are placed in a mould which is filled under vacuum with resin epoxy,” he said. “Fiberglass reinforcing mesh is used to further strengthen the windings, which are cured in a heat-controlled oven. This process also prevents air voids, and the resin in CRTs is non-flammable.” said Trafo Power Solutions Managing Director, David Claassen.

These designs have also made advances in reducing losses, and thereby improving efficiencies, Trafo said. “The use of OWTs, VPIs and CRTs offer considerable savings in energy costs of their life-spans – which for CRTs, for instance, averages about 20 years,” Claassen said. “Despite the slightly higher capital cost of around 20%, these technologies can repay the price differential in just four years.”

Claassen said low loss cast resin transformers are being used exclusively in many parts of the world, including Europe and North America. Although there is a 12 to 15% premium on these, the payback period is between two to four years, he said. These are now available for the African market from Trafo Power Solutions.

Source: International Mining