ACTOM Power Systems (APS) has been awarded a contract for the establishment of an extensive new 88/11kV intake substation in northern Ekurhuleni, an area poised as a major industrial growth point.
The new Witfontein Ext 90 main intake substation will occupy a 1.5ha site adjacent to Eskom’s Esselen 88/11kV substation. It is being established as a self-build project by a private sector developer on behalf of the City of Ekurhuleni, with the initial goal of powering a new IT facility.
This graphic shows the layout and contents of the extensive new 88/11kV Witfontein Ext 90 main intake substation that ACTOM Power Systems has been contracted to establish in northern Ekurhuleni.
“But the new substation goes well beyond catering solely for this project’s immediate demand, as it will also provide a secure backbone for longer term development and expansion of the entire district,” said John McClure, Power Systems’ Operations Manager.
In addition to 80MVA of 11kV power dedicated to the developer’s campus, the new substation will be initially equipped with a further 40MVA to cater for immediate municipal supply needs over the next few years.
“At the 88kV level the new substation provides Ekurhuleni Municipality with the flexibility and capacity to reconfigure the surrounding electricity distribution network from a basic rural layout to a fully-fledged industrial-purposed system,” John commented.
The project includes the erection of two 88kV incomer bays from the adjacent Eskom Esselen substation to the new substation and four outgoing 88kV overhead feeder bays for the extended district distribution.
The substation contract, worth over R70-million, was awarded to Power Systems in November 2020 and is scheduled for completion in October 2021. “This is a very tight programme, resulting from a delay caused by geotechnical complications surrounding a dolomite rock formation that could ultimately lead to sinkholes,” John said.
This necessitated the appointment of a civil engineering consultancy to design specialised bulk earthworks, drainage and reinforced concrete raft foundations for ACTOM’s equipment to attain sufficient loss of support coverage to withstand any foreseeable ground subsidence.
“Our responsibility consequently shifted towards integrating the electrical and civils interfaces and installing the substation underground earthing during the initial design and construction phase,” John pointed out.
The bulk of the equipment for the substation will be supplied by ACTOM group divisions, as follows:
l Three 40MVA 88/11kV power transformers manufactured and supplied by ACTOM Power Transformers.
l HV circuit breakers, current transformers, voltage transformers, isolators and surge arrestors supplied by ACTOM’s High Voltage Equipment division.
l NECRT transformers manufactured and supplied by ACTOM Distribution Transformers.
l Battery chargers and batteries supplied by ACTOM’s Static Power business.
l Power and control cable and accessories supplied by ACTOM Electrical Products.
In 2018 APS was contracted by the same customer on a similar self-build project to extend the 132/11kV Airport Super Substation adjacent to the OR Tambo Airport to provide additional power needed for a related expansion project in Isando.
The extension contract required special vertical-make isolators identical to those installed in the original Airport Super Sub many years earlier. These isolators were obsolete, but ACTOM undertook to co-opt the services of the original designer, who was eventually tracked down after a prolonged search, and arranged with ACTOM High Voltage Equipment to manufacture a batch of these bespoke isolators for installation in the substation extension.