Electricity and Control December 2022

TRANSFORMERS, SUBSTATIONS + CABLES : PRODUCTS + SERVICES

SA manufactured mobile switching station for EDM, Mozambique

Reinforcing its reputation as a supplier of cost-effective custom-designed mobile power solutions, Zest WEG has recently completed the delivery of a mobile switching station to Mozambique’s national power utility EDM ( Electricidade de Moçambique ). The 33 kV switching station, complete with 36 kV rated switchgear, is housed in a purpose built enclosure installed on a double-axle trailer and includes all protection requirements to allow for quick connection and safe operation at all times. “At Zest WEG we regard Mozambique as a key strate gic market and we are delighted to have completed this order successfully,” says Sollie Herbst, Senior Manager, Energy Systems at Zest WEG. He adds that although Zest WEG does not have a branch in Mozambique, it has an established Value-Added Reseller in the country that can provide support – together with Zest WEG in South Africa – to customers in the country. The switching station was designed and manufactured in South Africa by Zest WEG, with the lead engineer on the project being Dumisani Dlamini, Energy Systems Engineer in the company’s Energy Systems division. Mozambican engineering company MESAT, acting on behalf of EDM, set out the specifications and end-user requirements to be met. Dlamini says the main challenge on the project was to incorporate all the functionalities required by EDM into a

single, compact, prefabricated solution and, at the same time, to minimise the overall size and mass of the unit to enable it to travel along public roads without any special permits being needed. In addition, the switching station had to be able to in terface with the most recently developed technology for supervision, control and protection and incorporate ad vanced safety interlocks, both mechanical and electrical. Secondary plant, such as protection relays and devices, was sourced to be in line with EDM’s substation standards. Dlamini points out that one of the advantages Zest WEG has in designing projects of this nature is its ability to build its own enclosures. “We don’t make use of standard containers and therefore are not limited by standard siz es,” he says. “By undertaking our own fabrication, we can produce enclosures which can comfortably house all the components of the switching station without any need for compromises due to space restrictions.” Dlamini adds that the design adopted by Zest WEG simplifies on-site installation. “The unit is completely pre tested, prefabricated and pre-wired. In essence, it’s a ‘plug-and-play’ solution which can be rapidly deployed to wherever it is needed. There is no need for support infrastructure on site, such as a specially prepared laydown area, and no requirement for craneage, as would be needed with a skid-based solution. This means the switching station can become operational soon after arriving on site.” Zest WEG can normally supply its mobile switching stations within 28 weeks of receiving an order but, in this case, was able to slightly better this time. “The design and fabrication proceeded smoothly and we were able to de liver well within the promised timeframe,” says Dlamini. Commenting on the pos

Dumisani Dlamini, Energy Systems Engineer at Zest WEG.

sible applications for the switching

The 33 kV mobile switching station is ideal for routine maintenance or as a temporary stand-in when an existing station has failed.

26 Electricity + Control DECEMBER 2022