Reinforcing its reputation as a supplier of cost-effective custom-designed mobile power solutions, Zest WEG towards the end of last year completed the delivery of a mobile switching station to Mozambique’s national power utility EDM (Electricidade de Moçambique).
The 33 kV mobile switching station can be used in routine maintenance or to assist with temporary 33 kV distribution.
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 strategic 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 interface with the most recently developed technology for supervision, control and protection and incorporate advanced 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.
By design, it provides for safe and quick MV switching at any site.
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 sizes,” 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 and, in this case, was able to slightly better this time. “The design and fabrication proceeded smoothly and we were able to deliver well within the promised timeframe,” says Dlamini.
Commenting on the possible applications for the switching station, Herbst says EDM stipulated that it should be a self-contained, multipurpose unit able to accommodate a range of operational scenarios, including working in areas with limited infrastructure.
“It can be used in emergency applications where it replaces an existing switching station that might have failed, or it can be used in a standby role where it assists with temporary 33 kV distribution,” he says. “It’s also ideal for routine maintenance projects, where it might replace – for example – a switching station that is temporarily taken offline. It is also, of course, suitable for any project under construction which might need a temporary 33 kV network distribution. It is quite simple to tap this unit into an overhead line and feed power directly to the site.”
The mobile system delivered to EDM follows closely on another recent notable success for Zest WEG in Africa, which saw the company supplying a 50 MVA mobile substation, one of the largest ever built in South Africa, as well as a 33 kV mobile switching station, to Electricité de Guinée, the national electricity utility in the West African country of Guinea.
The scope of the turnkey project included three trailers with specialised equipment, one of them being a cable reel trailer with all power and control cabling needed to connect the mobile substation and the mobile switching station trailers into an integrated mobile energy system.
“The latest Mozambican order as well as the Guinean project highlight Zest WEG’s ability to design and manufacture mobile solutions for almost any application, anywhere in Africa,” says Herbst. “We believe there is a significant and growing demand for solutions of this type, given that the continent’s electrical infrastructure is growing fast. Our delivery on these latest contracts underlines our ability to meet this demand.”
For more information visit: www.zestweg.com
