The 2.4 MV impulse
generator in
Actom
Power Transformer’s

new test facility
 
11 September 2013 – Recently power transformer group, Actom Power Transformers celebrated 50 years in business by officially opening the company’s recently upgraded test facility. This comes after the latest expansion of its plant capacity to include production of 315 MVA generation and transmission transformers for Eskom. The company says that the new test facility, established at a cost of over R30 million as an addition to its existing test facility, is the most advanced facility of its kind in Africa.

Actom Power Transformers was originally established at a site in Wadeville near its existing premises in 1963 as the local subsidiary of Bonar Long of Dundee, Scotland. The company, then named Bonar Long National Trading Company, began with the manufacture of distribution transformers and within a few years extended into power transformers. It moved to its present site in 1970. After the NEI group acquired it in 1996 the company concentrated exclusively on manufacturing power transformers.

After Actom took over ownership of the company in 2001, Actom Power Transformers grew rapidly as a result of a series of plant expansions and technological advances aimed at diversifying its product offerings and increasing its market share in the local market, especially to Eskom, its foremost customer.

Group executive director Andries Tshabalala says, “During the 12 years since being acquired by Actom, the company’s turnover has increased 5.8 times or 600%. The company has greatly enhanced its status in this respect through the technological advances and production capacity expansions it has achieved – especially within the past six years.”

To illustrate this, Tshabalala says that the company’s highest rated transformers have progressively increased from 40 MVA at 132 kV in mid-2007 to 315 MVA at 275 kV today.

Willi Felber of Felber Engineering says that over the past 10 years, the company has improved its technologies and manufacturing capabilities. To start with, it upgraded to produce standard power transformers for Eskom of up to 80 MVA, from 40 MVA previously.  

Felber says that Actom Power Transformers has since supplied four 60 MVA transformers with oil directed and oil forced cooling for Cape Town’s Steenbras power station, two 120 MVA transformers for a copper mining project in the Democratic Republic of Congo and some of the first three-winding 110/55 + 55 MVA unit transformers with oil directed and oil forced cooling for Kusile power station, while 315 MVA auto-transformers for eThekwini municipality are currently in production.

Charles Kalima of Eskom reaffirmed Eskom’s commitment to actively encourage local manufacture of the electrical equipment it requires. Eskom has formulated a policy framework for localisation in which 42 items of power generation equipment have been identified for local manufacture and for creation of jobs over the next five to 10 years. These items, which include transformers, would require a minimum local content of 70%. He says that for locally manufactured transformers alone it is envisaged that R10 billion will be spent during that period.

Actom Power Transformers’s new test facility has been installed in a one-bay extension of the high bay that formed part of the company’s most recent plant extensions. Occupying four floors served by a dedicated personnel lift, the facility is used to test transformers of up to 315 MVA at 275 kV – a substantial advance on its predecessor, which tests transformers of up to 45 MVA at 132 kV.

Used primarily to perform dielectric tests, measure no-load and load losses and perform temperature rise tests, it is a fully automated PLC/SCADA-controlled facility. The test instruments are interrogated by the computer, which calculates the test results automatically and produces a comprehensive test report.

The equipment installed comprises a 15 MVA 11 kV alternator driven by a 6.5 MW 6.6 kV synchronous motor, augmented by a 38.5 MVAR 11 kV capacitor bank and a 38.5 MVAR 44 kV capacitor bank. This equipment is coupled to a 60 MVA step-up transformer to increase the voltage from 11 kV to 80 kV. Furthermore, a 2.0 MVA 2.2 kV 200 Hz alternator driven by a 600 kW 1.0 kV synchronous motor is installed for induced over-voltage testing.

The facility is also equipped with a 2,400 kV impulse generator with an energy capacity of 240 kilojoules, augmented by a Glaninger circuit for lower voltage impulses. This generator is again a big advance on the company’s other test facility, in which the impulse generator’s capacity is 1,200 kV and 60 kilojoules.

Ben Jansen, the company’s test consultant, who designed and commissioned the facility and assisted in procuring the equipment for it, says, “It is one of the most modern test facilities in the world. In addition to fully conforming to international test standards, it meets Eskom’s extremely stringent requirements, which include a unique 30% overload test.”