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Power Line and Substation Design

Trans-Africa Projects (TAP) specialises in the design of overhead power lines and the supporting structures for these lines. We have been involved in various projects from 11 kV through to 765 kV voltage levels for both new-build and refurbishment/normalisation projects.

Trans-Africa Projects is frequently engaged in different engineering aspects of projects, and the full range of services offered is outlined below.

Conceptual Designs

The ability to influence and reduce total project cost is best achieved in the early stages of a project when the project is conceptualised and the feasibility and alternative solutions are determined. In the power line industry early decisions can have a large impact on total project costing, typically the size and type of phase conductors to be installed as well as the actual line route selected. These two functions are drivers of the other cost components of the line.

The services that Trans-Africa Projects considers at this stage of a project include route selection, conductor optimisation, conceptual line profile utilising available Digital Terrain Model data and order of magnitude costing.

Preliminary or Detailed Line Designs

Trans-Africa Projects is often engaged by clients in different roles but the two most common scenarios are briefly described below.

In the first scenario, Trans-Africa Projects is appointed as the owners’ engineer and performs preliminary designs and creates functional specifications to enable EPC contractors to bid on and execute the detailed designs under Trans-Africa Projects’ approval.

The second scenario is when Trans-Africa Projects is engaged as an EPCM consultant, where Trans-Africa Projects will provide the full design service including preliminary and detailed designs to suit the project and client requirements.

Insulation Coordination and Electromagnetic Compatibility Studies can be done where new designs are implemented.

Some of the deliverables offered in these design scenarios are highlighted below:

  • Line profiling (performed in the industry standard package PLS-CADD©) typically using aerial LIDAR or conventional survey data as per client’s requirements and specifications
  • Cost estimation and alternative design comparisons
  • Structure and foundation selection and/or design
    • Pole designs – material choices consist of wood, concrete, steel or RFP as suited to the project requirements
    • Steel Lattice Tower designs
  • Constructability plans including site access planning, outage planning and phase configuration confirmation
  • Geotechnical investigations
  • Optical fibre designs for communication and protection of assets (including OPGW, ADSS and wrap installations)
  • Compilation of:
    • Design reports and presentation of design at client Technical Evaluation Forums
    • Specifications for new installations
    • Specifications for refurbishments and retrofits to match with existing infrastructure
  • Technical tender evaluations
  • Engineering support during construction including assistance with Factory Acceptance Testing and tower proto-type testing


Substations are the key assets in a power system throughout generation, transmission, sub-transmission and distribution. Trans-Africa Projects supply substation design solutions that efficiently support the reliable supply of power for all voltage levels. With decades of experience and proven excellence in consulting and design, Trans-Africa Projects has successfully completed a vast number of substation engineering projects constructed throughout South Africa and internationally. Trans-Africa Projects’ substation design engineering division’s proud tradition in delivering comprehensive and innovative design solutions as well as quality standards and specifications results from its experienced and qualified team of professional substation design engineers and technologists.

Our clients benefit from the competence and dedication infused within the substation design team’s strong attributes in both primary and control engineering disciplines. Our centre of excellence incorporation ensures that Trans-Africa Projects specialists constitute and participate in technical coordination to deliver customized design solutions comprising of primary– and secondary technical and civil aspects of a substation design.

Trans-Africa Projects’ substation design division is a one-stop supplier of design solutions for substation design services. We carry out thorough assessments, analysing and understanding substation configuration, layout, key elements and principles, equipment- and functional specifications which we incorporate and administer within our substation engineering designs.

The design focus on the unique or specific requirements for each substation and may include GIS and AIS technology.

Trans-Africa Projects’ substation design team designs for both brown– and greenfield type projects for various system voltages (low, medium, high and extra high) whether it is for conceptual (EPCM), preliminary and/or detailed required design level (EPC).

Our substation designs include site selection, civil, structural and electrical works specifications, designed construction and execution drawings, bills of materials and activities (BOQ), quality control- and equipment specifications.

Apart from our design services we offer other services include factory acceptance test witnessing, quantity surveying, tender evaluation, site acceptance testing, commissioning supervision and training for substation engineering.