5 June 2013 – Two 315 MVA, 400 kV transformers were recently manufactured for the city of Tshwane in South Africa. These were supplied by Powertech Transformers, a subsidiary of Powertech and the JSE listed Altron group. These transformers are for the new Wildebees infeed-station which is situated on the eastern side of Pretoria. This is the first 400 kV substation for the Tshwane municipality. The largest transformers that the company has manufactured for Tshwane previously were 300 MVA 275 kV units.

The above 315 MVA 400 kV transformers were designed, manufactured and successfully tested in Powertech Transformers test department in its Pretoria West factory with only local engineers involved.

Some details of the components and material are as follows:

  • At least 60% of local copper was used on this design which was sourced from sister company Aberdare Cables.
  • Locally manufactured Zenox/Varistors.
  • Insulation material from Powertech Insulation (another sister company).
  • The units without oil weigh 186 tonnes each and a total mass of 314 tonnes once oil-filled.  The length measure is 17 metres, width 7.4 metres and height of 9.45 metres.

The above two 315 MVA transformers are of strategic importance to Pretoria as they are  part of the first phase of the new Wildebees 400/132 kV infeed-station which is required to supply electricity to the Tshwane bulk electricity network because of the rising demand due to the increasing growth of the city. Kungwini was also recently incorporated into the Tshwane municipal area which has resulted in a further increase in electricity demand that has to be catered for. The Wildebees infeed-station will form part of the major infeed-stations Kwagga, Njala and Rietvlei where electricity is supplied directly from Eskom. The Wildebees infeed-station is the first 400 kV supply voltage that Eskom will distribute to Tshwane where the existing voltages are 275 kV and 132 kV.  
Bernard Meyer, CEO Powertech Transformers says “apart from Eskom there are only a small number of customers buying transformers at this voltage range in Africa.”