Sparks Electrical News June 2022

CONTRACTORS’ CORNER

5

TES partners can help fill the skills gap for the deployment of independent power producers

A s South Africa gears itself toward the Inde pendent Power Producer (IPP) market, the country is poised for economic growth and socio-economic development. Aside from bringing much needed electrical power generation capacity, these projects will also facilitate job creation, social upliftment, and local industry development. How ever, delivering the skills required for these projects – particularly in the rural areas where the renewable generation plants are being developed – can prove to be a challenge. In addition, there is the need to create long-term, sustainable economic develop ment around projects that are temporary in nature. A Temporary Employment Services (TES) provider can assist on both counts and help to bridge the skills gap to assist with the successful deployment of IPPs. The Renewable Energy Independent Power Produc er Procurement Programme (REIPPPP) introduced designated local content, where 40% of an IPP project spend must be sourced locally. This ruling creates tremendous opportunity for our economy, including a significant positive impact on job crea tion, since the current REIPPPP Bid Window 5 is ex pected to create thousands of jobs, and future bid Opportunities and challenges on the horizon L ittle or no care is taken when domestic, com mercial or industrial miniature circuit break ers, MCBs, are selected for use or replace ment. But there probably should be if the existing brand is not to be retained. Specifications are generally no more than a brand or equivalent, if indeed even specified. Within the South African context, we have rather unusual options, not always readily known beyond the brand, and locally designed and made, to boot! As this topic is based on the technology of these circuit breakers let's make sure we have an under standing of what technology is available as well as potential problems that may be encountered in the use of the various technologies. The problem here, from the outset, is that from the outside you do not actually know what tech nology you have. Having brand knowledge is more useful, of course, but replacing on price alone is hit and miss. Locally this is more likely to be miss, as the hydraulic mechanical is far more rare from a supplier number point of view. There are currently three technologies developed and commercialised in circuit breakers generally but one of these has not progressed to the MCB ranges, mainly for space and cost reasons. The fourth technology is a semiconductor-based stand in the side lines, waiting for a break dependant on technology advancement. Externally, there is really no identification of the technology to the untrained eye and without confir mation from the manufacturer, would require open ing to confirm.

A provider with experience in the energy sector as well as relationships in the communities can help IPPs to navigate and manage the intricacies of the relationships between the community and unions to mitigate any risks and concerns for the IPP. In addition, a TES provider can manage the full recruitment process along with the payroll, human resources, and industrial relations, and provide a pool of skills to draw from at short notice. As one of the current challenges is a skills and experience shortage in the Renewable Energy Sec tor, it is imperative to give job opportunities to those with industry specific certifications and qualifica tions as it provides valuable ‘on the job’ skills train ing and development together with sought after work experience. This approach will not only ensure we grow our existing labour force to meet the de mand for a skilled and experienced workforce for our energy sector, will also help these candidates to maximise future employment opportunities. A reputable TES provider is well positioned to assist in this regard. TES providers are committed to local economic development objectives and will continue to play a vital role in assisting IPPs to meet the local con tent target required by the REIPPPP. Success lies in partnering with a TES provider with a solid under standing of the renewable energy sector, the South

windows will bring further job opportunities. However, it also creates challenges for the IPPs. As renewable energy is still new to South Africa, one of the main challenges we face is a shortage of lo cally available skills. While there are individuals with the necessary certifications and qualifications, they often do not have experience specifically within the energy and renewable energy sectors. Furthermore, when it comes to engaging with ward councillors and community leaders, manag ing these relationships requires dedicated attention and a significant understanding of the South Afri can market and labour force. Contentious issues like wage negotiations can increase the potential risk of strikes or unrest if they are not expertly and successfully managed, which could result in very costly delays. Temporary problems In addition to these challenges is the fact that the construction phase of each site requires certain skills on a temporary or project only basis, which can be quite difficult for an IPP to manage when try ing to source the right talent. This includes civil, me chanical, electrical, and engineering skills, as well as new skills required to work with solar panels and inverters. A reputable TES provider can therefore be hugely beneficial in addressing these challenges. spective and, in pure numbers, is the most prolific. As the name suggests, this makes use of the fact that heat is produced as a byproduct of the current through a conductor. In this case the heat is applied to a bi-metal strip* which flexes over time resulting in the mechanism tripping the current and thus of fering the cable protection**. This technology has been highly honed over the years and costs have thus dropped significantly, but some shortfalls can not be designed out unfortu nately as they are inherently there due to the tech nology itself. Hydraulic Magnetic The second oldest patent stated that the magnetic principal that displays with current flow can also be used for cable protection. The current flows in a coil attracting a metal core in a hydraulic fluid un til it reaches the magnetic polepiece and trips the mechanism, again protecting the cable. This technology does require a degree of fine manufacturing tolerances and costs are higher than the thermal types. Costs have dropped as automa tion equipment has become more able to produce consistent tolerances and also because of the equipment being highly automated. Costs remain higher than thermal types but the technology posi tives mean that they are exclusively used for spe cialised protection as in rail transport and telecoms world-wide. Because temperature has little to no effect, their use in climate extremes can also be highly advantageous. Electronic Magnetic Notwithstanding huge advancements in the elec tronic component field, using, for example, cell

Tania Govender, Sales Director at Worldwide Staffing.

African economic environment and local labour legislation. This enables IPPs to remain focused on their core function, which in turn ensures they can complete projects on time and within budget.

By Tania Govender, Sales Director at Worldwide Staffing

Enquiries: info@workforce.co.za

Circuit breakers – defining technology

case of current overload we need to understand why the protection is required. 1: Short circuits: Extremely high current can flow if there is a direct short circuit which may burn off or fuse off the cable unless removed in haste. That is the reason for all technologies to have a Magnetic complement as noted above. 2: Overloads: Depending on the actual overload damage over time is possible especially to the plas tic insulation. An inverse tripping is required in this zone. All tripping curves will display this has been achieved using all of the technologies discussed. Hopefully this brief outline of the technologies will give a summary of why some care should be taken in specifying or replacing MCBs. The subject can be rather complex if going into the details is required. If you intend replacing an installed unit with the same type and from the same manufacturer, you probably cannot go far wrong. However, if replacing with another brand and another model you may un intentionally create a problem for later, if not found earlier. No contractor wants to be recalled to site to deal with any issues; there simply is no economics in this approach. Flack has recently retired from industry and believes he still has valuable in-depth knowledge of the South African electrical landscape due to wide experiences gained in his 45+ years working career. In these try ing COVID-19 times, Flack can provide online train ing to keep your staff up to date on all aspects of circuit breaker deployment. By Kevin Flack

phones as a base line, no current manufacturer pro duces distribution circuit breakers using this technology. As to why this is the case, bear in mind that since breakers are at 18 mm or 13 mm per module (13 mm being the world’s thinnest actually) raw space is required to help with arc quenching and, of course, costs are still at the extreme in comparison. The electrical current is past through a CT/Toroid and the output sent to an electronic circuit for eval uation. Should there be a need this then trips the mechanical breaker. Great strides are being made in larger MCCB and air circuit breakers (ACBs) with this technology however, the main limitation is still cost based. Us ing the cell phone story as an anology, one should possibly never say never … * Bi-metals A bi-metal strip has a steel-based metal/alloy fused to a copper-based alloy. Under heating

Thermal Magnetic This technology is the oldest from a patent per

conditions, the copper side displays a higher expansion rate and so bends the strip. All bimetal MCBs have a derating curve applicable as variation from the set ambi ent is also noted. Besides having basic knowl edge of the brands available, some understanding of what technology is being offered will go a long way in prevent ing problems later on. ** Cable protection In order that the circuit break er can offer protection in the

Technology comparisons Conditions

Thermal Magnetic

Hydraulic magnetic Trips slightly faster >80 °C holds rating however

Electronic magnetic

High temperatures

Trips under rating >40 °C - 10-20% rating variation possible Trips over rating <0°C +10-20% rating variation possible

No Impact

Low temperatures

Trips slightly slower <20 °C holds rating however

No Impact

Orientation, gravity

No impact

Design impact Refer to manufacturer

No Impact

DC current

Possible

Better to use specific design Better to use specific design

Better to use specific design

High / low frequency

Possible 400 Hz trips early Only excess heat 

Design impact Refer to manufacturer

Non sinosoidal wave type

Dramatic on high distorted waves CT maloperation possible

High limits

Email kevin.flack@outlook.com

SPARKS ELECTRICAL NEWS

JUNE 2022