A new R100-million test bay at Eskom's transformer repair subsidiary Rotek Industries, in Rosherville, Germiston, has been officially opened in a bid to reduce the time and cost associated with transformer maintenance and repair.

The workshop is the only one in Africa capable of refurbishing, repairing and testing, under one roof, the largest transformers operational within the Southern African electricity supply industry.

It can test transformers from 10 MVA to 910 MVA and to Eskom's highest power system normal voltage levels of 765 kV.

Eskom chief commercial officer and Rotek Industries chairperson Dan Marokane says that the investment is supportive of the utility's larger multibillion-rand investment programme, as it sets in place the supporting infrastructure required to ensure the proper maintenance of the utility's long-life assets.

However, he adds that, while Eskom will remain the facility's main customer, it will also be opened up to regional utilities, as well as private businesses requiring transformer maintenance and even upgrading services.

Eskom currently has a fleet of 120 major transformers at its various power stations, more than 500 associated with its transmission business and thousands of smaller distribution transformers.

Rotek Industries CEO Les Carlo reports that, prior to the investment, repaired transformers were moved to a facility in Pretoria, where testing could take weeks to complete at a cost of between R1,5-million and R3,5-million a unit.

The transformers had also, hitherto, been subjected to the rigours and risks associated with transportation and loading, which has been "eliminated" with the development of an in-house facility.

The test bay incorporates the latest testing technologies, including a 10-MVA regulator set, a 60-MVA transformer, static converters for power frequency and high frequency tests; 191-MVAr capacitor banks, a 800-kV Hi-pot for separate source testing, a 1,6-MVA transformer for auxiliary support; and a Scada communication and control system.

Impulse generators, which simulate the influence of lightning storms on transformers, have also been installed, while the digital measuring instrumentation is able to deliver a measuring accuracy of less than 0,05%.

In commissioning, the facility completed a heat run and a type test on a 700-–MVA transformer for one of Eskom's power stations.

 

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