Sparks Electrical News March 2022

CONTRACTORS’ CORNER

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Zest WEG delivers its biggest mobile substation yet

How to protect electrical devices

L everaging its considerable in-house expertise and local manufacturing capability, Zest WEG recently custom designed and manufactured one of the largest mobile substations ever built in South Africa. The 50 MVA mobile substation – destined for Guinea – includes a dual voltage rated mobile trans- former produced by WEG in Brazil, according to Ber- nard Mitton, engineering team leader for integrated solutions at Zest WEG. The substation will be com- missioned early in 2022. “This is a full turnkey project procured by Robust- rade in Dubai for the Utility Company of Guinea, called Electricité De Guinée,” says Mitton. “Our in-house team co-ordinated the electrical, civil and mechanical designs, as well as the engineering solutions for the customer.” The full project includes three trailers of equipment, and allows the end-user to step down power from the main national grid at various geographic points as required. High voltage power is tapped from existing overhead line with a specifically designed and manu- factured tee-off solution connecting the supply into the mobile substation, where it is stepped down from 110 kV or 60 kV to 20 kV or 30 kV depending on requirements. “From the 50 MVA mobile substation, the supply is then distributed to a 30-20 kV mobile switching sta- tion, containing an incomer and five feeders,” he says. “Mini-substations can be fed directly, or a cable can feed to a junction box in the field, usually where there is an existing cable in the ground.” As part of the project, Zest WEG designed and sup- plied a cable reel trailer with all power and control ca- bling needed for the mobile transformer and mobile switching station. Included on this trailer are 30 kV field junction boxes to assist with the cable connection between exiting cables already installed and the sup- ply cables from the mobile switching station. These boxes allow for up to three feeder cable connections. The advantage of this design, he notes, is that the junction box becomes a termination point. The termi- nation ends of the on-site cable do not need to be re- done, and all that is necessary is a bolt-on connection. “This mobile substation solution is suitable for both temporary and permanent installations, so it can be used in a range of applications,” Mitton says. “For emergencies, it can replace an existing substation transformer in the event of failure, and for standby ap- plications it can handle temporary overloads at sub- stations.” It can also be put to use during routine mainte- nance, to manage the loads of existing substations The Sappi Skills Centre was officially opened in Feb- ruary 2018 by the CEO of Sappi Southern Africa Alex- ander Thiel. This training facility has seen more than 240 learners graduate from the various programmes which include basic electrical, carpentry, home mainte- nance and welding. Currently there are 61 learners in the Sappi Appren- tice Programme who are involved in various stages of phase training with 12 of these learners scheduled to complete their discipline-specific trade tests later this year. The Sappi Skills Centre will also be inducting a fur- ther 15 apprentices for the 2022 cohort, with 10 of these learners coming from Sappi’s flagship Pre-Apprentice Programme. The Sappi Skills Centre is resourced with experienced trainers in the fields of electrical, instrumentation and me- chanical engineering. In addition to the community train- ing, technical training is provided for apprentices, techni- cians-in-training, engineers-in-training and various skills development courses for employees across all Sappi KZN Mills. The skills centre is currently accredited by the Quality Council for Trades and Occupations (QTCO) as an Electrical Skills Development Provider (SDP).

during load shedding P ower utility Eskom has, since the start of the year, been implementing load shed- ding on a frequent basis. This is due to a shortage of generation capacity following the breakdown of two generators. Load shedding in- creases the risk of damage to compressors and motors, such as fridges and pool pumps, which adds unnecessary maintenance and replacement costs for already cash-strapped South Africans. Dr Andrew Joannou, Business Development Manager: Engineering & Innovation Technol- ogy at CBI-electric: low voltage says that volt- age instability before and after load shedding are among some of the harshest negative effects on our electrical grid. “This means that there may be voltage fluctuations that are either higher or lower than the standard voltage supply of 230 V ac.” He adds that these high and/or low voltages can damage appliances and the best way to pro- tect against this is to only allow voltage to the ap- pliance once it has stabalised. “With smart home automation devices, users can quickly and easily set a minimum and maximum ‘safe operating voltage range’ via an app. Hence, if the voltage is not stable, the smart device will police the volt- age levels and only allow power to the load (ap- pliance) when it is within a safe operating voltage range.” CBI-electric: low voltage, previously known as Circuit Breaker Industries or CBI, is located in Jo- hannesburg, South Africa. CBI-electric: low volt- age is a supplier of quality low voltage electrical distribution, protection and control equipment. The foundations of CBI were established in 1949 as a joint venture within the then Heinemann Electric Company in Trenton, New Jersey, USA. After a merger with Fuchs Electrical Industry dur- ing 1986, a new company called Circuit Breaker Industries (CBI) was created. CBI-electric: low voltage is fully owned by Reunert, which is listed on the JSE. Over the past 10 years CBI-electric: low voltage has established itself as a supplier of specialised precision protection products in niche markets around the world. Based on the success of this strategy, the majority of our production output is exported.

of components,” says Mitton. “The substation’s trans- former was specifically designed and manufactured by WEG in Brazil for mobile applications.” Other special features include bushings made of composite silicon rubber, as well as an advanced me- chanical and electrical safety interlock system. The modular design simplifies on-site installation, as all equipment has been pre-fabricated, pre-wired and pre-tested before shipping. “This enhances the reliability of the solution, which translates into high availability and less maintenance,” he says. “It also simplifies the transport, logistics and commissioning.” The order for the mobile sub-station was placed just before the Covid-19 lockdown in early 2020, so the project had to be managed under challenging condi- tions. The factory acceptance testing of key compo- nents, for instance, could not be done in person due to travel restrictions – so this was successfully done through virtual platforms across different time zones. “All in all, we embraced the new communication technologies and proved once again that we could deliver to customer requirements even under unprec- edented conditions,” Mitton says. “Being able to meet the stringent requirements of Electricité De Guinée, through close collaboration with the Robustrade team, ensured the project was a suc- cess, proving this solution suitable for use across the region,” he concludes.

being maintained, repaired or inspected. This mini- mises the delay in taking out the unit due to load and other system constraints. The mobile substation can even be used to provide power for large project sites or mining sites of high importance. He highlights that the design and construction of solutions for mobile applications, including mobile generators, is one of Zest WEG’s strengths. The ex- pertise and capability within the business allows these units to be custom-designed to suit customer require- ments. In fact, none of the mobile solutions provided to date have been identical. “We have acquired valuable experience from many years of designing, manufacturing and supplying mobile solutions in modular configurable designs – mainly for Africa and Latin America,” he says. “These are not off-the-shelf products, but are cus- tom-engineered solutions to technically comply with user’s specifications, integral requirements, the op- erational environment, logistical requirements and the safety of the operating personnel.” The mobile substation includes innovative design features such as the integration of several functions into a compact, modular design. New technologies such as hybrid circuit breakers have been employed, along with disconnectors, earthing switches, ring-type current transformers, inductive voltage transformers and surge arresters. “All the functionalities are included in a single pre- fabricated solution, while space requirements for switchgear bays are reduced through high integration Trevino Sunker, Skills Centre Manager, stated that he was humbled by the enthusiasm of the young learners who were given the opportunity to develop themselves. “We have a number of success stories of learners who walk through these doors, not knowing fully what to expect and through their drive and tenacity, they walk out with a skillset that they can use to find employment, become entrepreneurs or become part of the Pre-Ap- prentice Programme. The Sappi Skills Centre is driven to uplift and empower our employees and community with specific and specialised skills that will supply a work- force that is both competent, efficient, and employable for the country’s growing needs,” he added. Brian Andrew, Managing Director for RS Components SA said that the company appreciated the opportunity to assist Sappi in achieving their goal to upskill the youth of South Africa. “Initiatives like this fall in line with RS Components’ global vision of inspiring and empowering the next generation of technicians and engineers. There is always a demand for skilled artisans such as electri- cians, handyman and mechanics and with the training that Sappi provides the additional option of starting your own business. At RS we’re really proud to be involved in such an uplifting programme and we look forward to seeing more young people being trained and employed in South Africa.”

Enquiries: www.zestweg.com

Enquiries: www.cbi-lowvoltage.co.za

RS Components supports SAPPI with skills development S appi’s Skills Centre in KwaZulu-Natal has recently received a donation of much-needed equipment- ranging from tools, safety gear and electronics valued at over R60 000 from RS Components South Africa.

Enquiries: www.sappi.com/sappi-skills-centres

Recruits simulating electrical work.

SPARKS ELECTRICAL NEWS

MARCH 2022