May 2014 – The CONCO group has successfully completed the three-year construction of an 89 kilometre long 400 kV transmission line from Eros substation near Harding in KwaZulu-Natal towards Vuyani substation in Mthatha in the Eastern Cape. The R270-million contract was awarded to CONCO by Eskom in 2011 – a significant achievement for the group.
“The project work began shortly after the awarding of the contract, and over the past three years CONCO designers, engineers and management working closely with their Eskom counterparts, have worked tirelessly to ensure that this major project was well engineered and constructed, produced to specification, within budget, constructed to the highest quality and within the stipulated time frame,” says CONCO’s Joseph Mahlangu, project engineer for the Eros/Vuyani project.
This is the first 400kV line in the former Transkei area and the major benefit is the increased power transfer capability and network strengthening in the Mthatha area and surrounding regions. The current distribution networks are also being upgraded to take power from the new Vuyani substation located at Mthatha. This will alleviate the problems that the Eastern Cape has been experiencing in respect of power shortages affecting municipalities and industry. The new line potentially creates opportunities for industrial investments and community upliftment
in the Eastern Cape.
“The scope of the project included design and installation of concrete tower foundations in various soil/rock conditions, supply and erection of galvanised steel lattice, transmission line towers to carry the greased ACSR Tern conductor with a single earth wire and optical ground wire (OPGW). The 400kV towers are self-supporting, crossed roped suspension and guyed lattice structures. Stringing and regulation of the Triple Tern (greased) ACSR phase conductor and single earth wire as well as supply, stringing, regulation and splicing of a single 48 CORE OPGW was undertaken. All OPGW associated hardware was supplied and fibre optic duct cable from the substation gantry to the control room patch panel was supplied and installed. CONCO was also responsible for the rehabilitation of groundwork and implementation of the environmental management plan,” commented Mr Mahlangu.
This project, as with all CONCO’s projects, had a strong social responsibility component and some of the major benefits were that over 200 temporary employment opportunities were created but not without the challenges of having to work with many tribal authorities to mitigate the risk of work stoppage should there have been protest action by the communities for employment. CONCO also donated 200 desks, 100 chairs, a microscope and a projector to Dudumeni High School in Flagstaff.
“Constructing a transmission line of this proportion, meant that certain challenges had to be overcome and these ranged from hilly terrain, difficult access with there being no nearby public roads in many cases, river crossings and overhead lines crossings (132kV, 33kV and 22kV). With regard to the supply of concrete, there were limited ready-mix concrete suppliers resulting in CONCO having to use one supplier based in Kokstad for the entire 89 kilometres, plus the hilly terrain meant that loading of concrete trucks was restricted,” said Mr Mahlangu.
“The Eros/Vuyani project stands out as a major success story for the CONCO group as we have proved our ability to project manage, engineer and construct a transmission line of this dimension. Eskom commended us for our experience and integrity and our full commitment to the project, and were impressed with our staff’s professionalism and analytical abilities. Eskom expressed that our effort as well as our attention to detail, quality, schedule and budget, led to this project being successful,” said Mr Mahlangu.
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