Dry-type transformers for motor plant mini-substations

22nd October 2021

Dry-type transformers for motor plant mini-substations

A 500 kVA cast resin type mini substation being offloaded for an outdoor application

Two custom-engineered mini-substations are to be supplied to a motor plant expansion near Pretoria. The units will include dry-type transformers, which are said to offer a number of benefits to the customer.

Trafo Power Solutions MD David Claassen says these benefits include security and environmental factors. “Used by both the private and public sectors, mini-substations must often be located in unprotected areas, making them vulnerable to vandalism and theft,” Claassen says. “The oil-cooled transformers are often targeted for the copper in their windings, as well as the oil for the cooling system.”

The dry-type transformer’s windings, by contrast, are cast in resin so the copper or aluminium cannot be readily accessed. There is also no oil to harvest, further reducing the incentive for criminals to destroy the structure. The two units will be located outdoors and will be used to power the lighting system and security requirements of the facility, as well as other loads.

“In terms of environmental considerations, the dry-type transformer does not require any additional protective structure like walls or bunds to contain leaking oil or fire,” adds Claassen. “These units also require very little maintenance, easing the managerial and technical burden on the owner.”

The two transformers are manufactured by TMC Transformers in Italy but the design and manufacture of the balance of the mini-substation is carried out in South Africa.

“This also allows us to fully test the equipment locally before it is delivered, installed and commissioned on site,” says Claassen. “We embrace the opportunity to manufacture locally as much as we can, to support local industries and enhance job creation.”