EKURHULENI
Lighting up one of Africa’s greatest cities
Within the world of construction, the fact that designs and their ensuing execution last well beyond their planned life is testimony to value engineering. The design and construction of the 1 400 MVA Sebenza substation for City Power ser ves as a classic example of an inter vention that extends the functionality of 1960s era electrical architecture.
A
s a starting point, City Power’s Sebenza substation is a vital link in ensuring sustained 24/7 transmission. Once fully commissioned, Sebenza replaced the older Kelvin substation in supplying a large portion (the eastern third) of the City of Johannesburg via a bulk power line corridor consisting of 16 power line circuits.
GIS building showing the back view of the installed 38 bay GIS switchgear
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IMIESA July 2020
Sebenza has the equivalent capacity to supply an estimated 700 000 households, in the process unlocking industrial, commercial and residential development. The process of implementing it was the responsibility of the PSW Nyeleti JV. “The key achievement was that the project team successfully constructed and incorporated Sebenza into the City Power network, while maintaining supply to existing customers, catering for the additional load growth during the project, and keeping within
City Power’s allocated budget,” says Juan-Dirk Voigt, director, PSW. Key elements within the project scope included the transfer of 2 x 275 kV and 16 x 88 kV existing power lines, while catering for the restrictions and limitations presented by the existing Eskom and City Power network. Not only did the Sebenza substation need to cater for the future 400 kV infeeds from Eskom, but also the integration and connection of the existing 300 MW Kelvin Power Station while in operation.
The old network Kelvin Power Station is an old (privately owned) power station dating back more than 50 years. Over this time, the load demand had grown to the present ≈450 MVA threshold, exceeding the 300 MVA capacity available.
Geotech image showing the Sebenza substation footprint
