MV Switchgear provides PTK’s and collector substation switchgear for two new wind farms

Jackie BenceWhat’s Watt

ACTOM MV Switchgear was awarded two contracts late last year for the design, manufacture and supply of pad-mounted transformer kiosks (PTK’s) to serve the wind turbine generators at two new wind farms.

The business unit is recognised by independent power producers and EPCM contractors for the reliability and efficiency of its PTK’s, which it developed and supplied for wind farms in earlier rounds of the national Renewable Energy Independent Power Producer Procurement Programme (REIPPPP).

The two farms, which form part of Round Four of the REIPPPP, are Golden Valley near Cookhouse in the Eastern Cape, comprising 48 wind turbines, and Excelsior between Swellendam and Bredasdorp in the Western Cape, comprising 13 wind turbines. 

The contracts, awarded by EPCM contractor OptiPower Projects, also include the design, manufacture and supply of the medium voltage switchgear required for the 33kV/132kV collector substations that will feed the wind-generated electricity into the national grid.

Further enhancements are incorporated in the latest PTK’s.

Aluminium-zinc coated mild steel is utilised in the manufacture of the LV assembly of the new PTK’s in place of galvanised mild steel used previously. In addition, many of the internal parts of the LV assembly are now made of aluminium-zinc coated mild steel, instead of painted 3CR12 steel. “The main advantages of using aluminium-zinc coated mild steel for these purposes are greater ease of fabrication and reduced fabrication costs,” remarked Greg Whyte, MV Switchgear’s Design & Development Manager.

The other components of the enclosure for the new PTK’s, besides the LV assembly, are a 36kV Schneider Flusarc ring main unit and a wind turbine transformer. The transformers, manufactured by ACTOM Distribution Transformers, have different power ratings for the two wind farms – those for Golden Valley being 2,8MVA units, while those for Excelsior are 2,75MVA units.

Greg said a temperature rise test conducted on one of the first PTK’s produced, established that the transformer installed within the PTK enclosure is able to supply its full rated power. “What this means in short is that the transformer is suitably designed to ensure that, despite the de-rating effect of the enclosure, it can be used at its full nameplate rating without exceeding the specified temperature rise limits,” he commented.    

Caption: One of MV Switchgear’s new PTK’s for wind turbines is given a final check over by a technician in the business unit’s Knights plant before being dispatched for delivery to one of the new wind farms currently under construction.

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