Zest Energy, part of the Zest WEG Group, is poised to complete a contract awarded by Eskom for the design, construction, supply and commissioning of four 22 kV mobile distribution switching substations, in line with the power authority’s policy of standardising this equipment across the board. Custom trailers have been designed to suit Eskom’s standard equipment dimensions and to remain within the South African road ordinance.
This project comprises a complete custom-designed solution that included the supply of four 22 kV medium voltage switchboards and involved other Zest WEG Group companies.
Zest Energy focuses on two main types of substation and reticulation projects — fixed conventional outdoor substations, typically up to 275 kV, and mobile substation solutions with a variety of voltages to meet different customer needs.
Managing Director, Coenraad Vrey says Zest Energy’s mobile power solutions came into being against a background of the high capital cost required for permanent and fixed power generation and substation installations.
Today the company manufactures mobile generators with the ability to feed power to multiple locations, which Vrey says is by far the most cost effective approach. In areas where new infrastructure or modification to existing infrastructure is required, mobile substations ensure that the power supply is not interrupted during the construction process. Also, since mobile substations can be supplied within a relatively short delivery period, they can easily be considered for use when fixed substations fail or when maintenance tasks are required on existing substations.
“Where mining operations have a lifespan between five and seven years, mobile substations present the perfect solution in terms of being temporary equipment integrated as part of the overall electrical infrastructure and the reduced delivery periods associated with such equipment facilitates quick solutions for electrical network problems,” says Vrey.
“Backed by WEG’s success with mobile substations in Brazil, we are now manufacturing this technology in South Africa with a high local content. WEG has also sent a mobile substation specialist to assist over the next few months with the growing demand from the African market.
“Although our company started out with an initial focus on power generation, we soon recognised that every power plant needs infrastructure and out of this necessity we introduced substation and co-generation offerings. Being part of the WEG Group has given us invaluable access to WEG goods, services and technology, as well as the Group’s decades of international experience in substation and infrastructure projects, notably in developing regions like South America.”
WEG has been building mobile substations in Brazil since 1992 and to date WEG has supplied 22 units with an additional 15 on order. All other components required for the mobile substations are manufactured and assembled in South Africa. Vrey says the two most important components of a mobile substation are the high-tech transformer and the trailer, which must comply with road and traffic legislation in regard to weight and equipment dimensions. The effects of trailer flex and movement on the integrity of the transformer design are also important considerations.
Zest Energy has extensive expertise in several different energy generation technologies. Whether a single component or a combination of power generation solutions is required, the organisation’s services include the supply, manufacture, erection and maintenance of power generation equipment. Projects range from complete, integrated power generation plants and co-generation systems, to custom engineered power generation solutions for new or existing mining and industrial companies.