Electrical component and cable suppliers ARB Electrical Wholesalers, a member of JSE-listed ARB Holdings, is set to play a significant role in the distribution of power generated by State-owned power utility Eskom and independent power producers (IPPs), particularly those participating in the Renewable Energy Independent Power Producer Programme.
ARB Electrical Wholesalers overhead line director Jason Burke says the company will supply materials to Eskoms ten-year Transmission Development Plan (TDP) for 2013 to 2022, which aims to meet the long-term requirements of electricity consumers in South Africa.
The initiative aims to upgrade and maintain the legislated adequacy and reliability of the country’s transmission grid to ensure that the network complies with the minimum reliability criteria for loads, power stations and the distribution of electricity gener- ated by new power stations developed by Eskom and IPPs, he explains.
Eskom group executive of transmission Mongezi Ntsokolo states in the latest ‘Transmission Ten-Year Development Plan: 2013 to 2022’ that the transmission sys- tem plays a vital role in the delivery of a reliable, high-quality electricity supply throughout South Africa and Africa by delivering electricity in bulk to load centres and large end-users.
“From there, the distribution networks owned by Eskom and municipalities deliver electricity to end-users.
“The transmission system needs to be well maintained to deliver a reliable supply of electricity and it also needs to be strengthened to meet changing customer needs,” stresses Ntsokolo.
Therefore, in light of the country’s aging, congested and inadequate electricity infrastructure, there is an urgent need for new and upgraded transmission lines, says Burke.
“Eskom’s TDP entails the addition of significant quantities of new line to the grid,” he says, adding that 3 700 km of 765 kV lines and more than 8 600 km of 400 kV lines have either been approved or proposed to electrify new areas over the next ten years.
Burke says the transmission projects will form the backbone of the electricity network, which will transmit power from the new power stations and the renewable-energy projects that are being built.
“This will, in turn, have an impact on the capacity of the distribution infrastructure, which will enable new areas to gain access to electricity and help uplift these local economies,” he says.
The company will provide a turnkey supply solution for Eskom and its specified contractors, as it can supply all the components needed to construct a line, including the aluminium conductors, insulators, metalware and the preformed line products.
“Our responsibility in this project is to supply the components needed to construct the lines. Materials need to be delivered in stages over the duration of these projects, sometimes at remote locations.
“We are well positioned to deal with this challenge, as we have a branch in each of the nine provinces,” says Burke.
He adds that the company also stocks the necessary tools, testers and safety equipment required for these installations.
“ARB’s focus has traditionally been on distribution, but our interests have expanded to transmission and substation supply, in line with new power stations which are now being built,” he says.
The overhead line division supplies material to distribution and transmission networks, ranging from 11 kV to 66 kV for distribution and 132 kV to 765 kV for transmission.
Burke states that the company recently launched new products that are likely to revolutionise the way transmission lines are built in South Africa and in Africa.
A new development, which he says will benefit Eskom’s TDP, has been the company’s appoint- ment last year by conductor manufacturer CTC Global as the exclusive distributor of the aluminium composite core conductor (ACCC) for the Southern African Development Community.
“More than 14 000 km of this product was installed at 215 project sites worldwide, including three projects installed by Johannesburg power utility City Power.”
CTC Global’s ACCC conductors, which are ISO 9001-2008 certified, have a carbon fibre core that replaces conventional steel core conductors. These conductors are designed to double the current carrying capacity over existing high-voltage transmission and distribution electrical grids and can increase system reliability by virtually eliminating high-temperature sag, result- ing in 30% to 40% reduction in line loss.
“ACCC conductors offer higher efficiency and enhanced capacity through extensive operating temperatures, compared with any other conductor type of similar design. “These conductors, owing to their high strength and low thermal sag features, also improve reliability without compromising structural integrity or safe ground clearances.
“The carbon fibre core is corrosion resistant and the ACCC conductors have twice the capacity of aluminium conductor steel-reinforced cable, owing to their steel to carbon fibre weight ratio reduction, and reduce line losses by up to 40%. They operate at lower temperatures than conventional overhead conductors under the same load conditions. This increases power efficiency and financial returns year after year over the life of the asset,” explains Burke.
He adds that this system requires fewer support structures, reducing support construction costs and installation time.
ARB has also been appointed the sole distributor of conductor manufacturer Fushicopperweld’s dead soft annealed Copperweld wire and strand in Africa.
“These low-corrosive earthing conductors, which have a strong steel core and copper cladding, are designed to replace conventional bare copper earth wire with various levels of conductivity, a low impedance path to earth, safe installation with compatible standard accessories to the bare copper earth wire conductor, theft resistance and extended service life
,” says Burke.
He highlights that Copper-weld wire or strand, designed for easy handling, has advantages over solid copper for earthing grids in substation and indus- trial installations. These include a high steel core strength, fatigue and corrosion resistance, excellent conduc- tivity and an extended service life in adverse conditions.
“Unlike Copperweld, solid copper conductors often need to be upsized to meet the mechanical demands within a system design. “Copperweld also has an almost zero scrap value, which deters thieves who sell copper as scrap.
“Any type of copper used by utilities for earthing is susceptible to theft worldwide. “Once the earth wire has been removed or damaged, a system is at risk of facing unforeseen fault currents and a higher probability of power outages, equipment being damaged and personnel being injured,” explains Burke.