Delivering more power to brighten South Africa’s future

Aug 10, 2023

How high-performance powerline wires are helping relieve the energy crisis in South Africa and supporting the growth of renewable energy by improving the efficiency of transmission and distribution networks.

Nearly two decades ago, a small company in a technology centre in California, US, introduced a new type of powerline wire known as ACCC Conductor. The company, CTC Global Corporation, is credited for inventing the world’s first and most highly proven Advanced Conductor deployed to over 1,100 transmission line projects in 65 countries worldwide. Generally considered a High Temperature Low Sag (HTLS) conductor, the ACCC Conductor is widely used to improve the electric power grid’s efficiency, capacity, reliability and resilience while supporting economic development and improving the lives of tens of millions of people.

In its global deployment, the ACCC Conductor has an unmatched history of improving the capacity and efficiency of constrained power grids. In Bangladesh, for example, the ACCC Conductor has been used effectively to double the capacity of the country’s existing power grid and cost-effectively connect several major new generation projects to the upgraded grid with new ACCC Conductor transmission lines. These investments, supported by international development banks, are helping deliver more power more reliably, and they are also helping reduce utility and consumer costs.

The improved efficiency of the ACCC Conductor pays for itself in a matter of months while offering a lifetime of benefits.

While the ACCC Conductor can carry twice as much power as conventional steel-reinforced ACSR conductors, the ACCC Conductor also reduces electrical line losses by ~30%. Simply stated, “the improved efficiency of the ACCC Conductor pays for itself in a matter of months while offering a lifetime of benefits – a very wise investment”.

Reduced line losses not only reduce fuel consumption, energy costs and greenhouse gas emissions for conventional fossil-fired generation resources but also free up wasted generation capacity. For new renewable generation resources, reduced line losses can help deliver more power and improve overall project economics to benefit developers and consumers.

The ACCC Conductor’s higher capacity and superior technology are also helping ‘future-proof’ the grid. In the past, conventional steel-reinforced ACSR conductors (introduced more than 100 years ago), often needed to be replaced due to their capacity limitations or ageing that can occur in highly corrosive agricultural, industrial, or salt air environments.

The ACCC Conductor uses an aerospace-derived hybrid carbon fibre core that is impervious to corrosion and cyclic load fatigue. Carbon fibre is twice as strong as steel and 70% lighter, making it ideally suited for this application. The high-strength core’s lighter weight allows for adding more conductive aluminium to the ACCC Conductor for the same conductor weight profile. Therefore, more power can be transmitted without a weight penalty, preserving existing cross-arms and reducing tower retrofit costs. Additionally, the added capacity allows load growth over time as regions prosper, demand increases, and new generation resources are connected.

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Quite simply, a great deal of Eskom’s power grid at 132kV and below is seriously congested, particularly in the regions with the highest demand. Given its economic and full-time load constraints, Eskom has little opportunity to install new corridors. Servitude (ROW) constraints compound the problem. The most effective and time-efficient approach is to reconductor these constrained corridors with Advanced Conductors.

ACCC Conductor is the most-proven conductor in this application. A simple reconductoring of the line, done at a fraction of the cost and time, dramatically improves capacity and reliability. Such a project, completed under an integrated plan to target the most constrained lines first, will improve key assets’ capacity, decongestion and reliability from the very start.

Additionally, a wave of new transmission corridors necessary to evacuate power from the Northern, Western and Eastern Capes to the load centres in the north is imminent. New power from the renewable energy-rich Cape provinces will not be utilised without decongesting the existing lines in the load zones. It will be constrained, and generation assets will be curtailed.

Eskom recognises the benefits that Advanced Conductors (HTLS) can bring. For example, Eskom issued a Request for Information (RFI) on HTLS conductors in March of this year, with a fast track to completion. The intent is to start this decongestion and capacity increase effort as soon as possible. Installation practices for Advanced Conductors are an important consideration. Advanced Conductors may use pure aluminium stranding or unique grips and terminations. The ACCC Conductor has some needs as well. These are simple precautions against bending the conductor beyond its rated bend radius; additionally, using a proven collet system in the dead ends to properly secure the composite core.

CTC Global has invested heavily in teaching and maintaining safe field practices for installing the ACCC Conductor. This training includes certified ACCC Master Installers who come to the site to train and supervise the crews for proper procedures and handling. Moreover, in an investment in local capabilities, CTC Global creates and trains a Master Installer Organisation that remains in-country to allow the effective use of the ACCC Conductor for future projects.

Advancement of the ACCC Conductor, the InfoCore System, produced by CTC Global, embeds optical fibres in specific locations within the conductor’s core that allow interrogation of the core, confirming core integrity before, during and after installation. Any damage caused by mishandling can be identified and corrected during installation.

With the ready availability of Advanced ACCC Conductors, correct handling practices, resident specialists, and extensive global use history, utilities such as Eskom can be confident that the benefits of these high-value conductors can be applied quickly to unlock the congestion experienced now and unblock the coming flow of new renewable power generation assets.

The ACCC Conductor core is manufactured by CTC Global to ASTM B-987-20 Standards and delivered to 35 CTC Global and ISO Certified ACCC Conductor manufacturing partners who sell the ACCC Conductor directly to their regional clients. ESI

About the author Marv Sepe is Senior Vice President of CTC Global Corporation, headquartered in Irvine, California and serves as General Manager of the company’s China-based joint venture business north of Shanghai. He is a senior executive with South Africa-based Green Transmission Company (Pty) Ltd. For more information on the ACCC Conductor contact CTC Global at [email protected] www.ctcglobal.com

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