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WEG quality confirmed by new NamPower contract
The Zest Group is supplying nine new WEG transformers to the Namibia Power Corporation (NamPower) as it upgrades its national power network to meet the growing demands driven by the mining, and specifically the uranium, industry in Namibia.
“Zest and WEG have forged a strong relationship in serving customers with rigorous equipment and service requirements,” says Gary Daines, projects director at Zest. “WEG is particularly renowned for the quality and durability of its transformers which it has been manufacturing for decades and which have become the technology benchmark in the industry.
“The contract with NamPower involves nine WEG transformers. The first, destined for the Van Eck Power Station in Windhoek, is a WEG 160 MVA 220/66 kV transformer. Six units, four of which are 25 MVA 132/66/22 kV and two of which are 10 MVA 132/66/22 kV units, will be used as spares.
“The final two transformers are 120 MVA 22/132/33 kV units which will be delivered and installed at NamPower’s Otjikoto Transmission Station near Tsumeb in Namibia in August this year. They are intended to supply power to the new Ohorongo Cement Factory and to enhance power supply to the far northern regions of Namibia. These two transformers were recently witness-tested under full load conditions by NamPower representatives at WEG’s facility in Brazil.
“What is especially significant about this new contract with NamPower is that the transformer which we are replacing at the Van Eck power station has been in operation since the 1970s, far exceeding its originally projected lifecycle of some 25 years. So the fact that a WEG transformer has been selected as its replacement is eloquent testimony of the confidence which NamPower has in WEG and the standard and quality of the product itself,” Daines says.
“We have been very satisfied with the exceptional performance of the WEG transformer to date,” concurs Horst Mutschler, head:transmission projects at NamPower. “The service we have enjoyed from Zest has also conformed to high standards. A further factor in NamPower’s decision to award the tender to Zest was the very competitive price for the equipment which not only fulfils the required specifications, but includes design features which establish it as one of the leaders in the industry.”
The first, 160MVA unit, destined for the Van Eck power station weighs 100 t and was rigged into position easily. Considerable planning was taken prior to installation since Van Eck is a working power utility and downtime had to be carefully minimised.
Both the 160MVA and the two 120 MVA transformers are fitted with the SERGI transformer protector. “In the event of a transformer short circuit, the protector is activated within milliseconds by the first dynamic pressure peak of the shock wave,” explains Daines. “This prevents transformer explosions before static pressure increases, thus saving equipment and buildings. It also facilitates a very quick internal repair of the transformer, thus sharply reducing plant outages.”
Manufactured in France, the SERGI equipment was shipped to WEG in Brazil to be fitted and tested. The complete unit was then shipped directly to Walvis Bay and subsequently transported to its final destination by road.
“Transformers are becoming increasingly important in general industry and mining. They are playing an ever more vital role in ensuring that electrical energy is available continuously at the appropriate voltage,” Daines concludes.
Important features on the WEG transformer include the design of the lockable offload tap changer which is conveniently positioned within the operator’s reach and which also enhances safety and durability. An innovative pressure-relief device channels oil away from the transformer into the pit, avoiding contact with personnel and thus preventing contamination. A further feature is the in-house developed corrosion resistant paint which enables the WEG range of transformers to operate in the most aggressive environmental conditions.
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