Losses and costs associated with HVDC and UHVDC transmission lines

  Reduction in electrical energy consumption requires power utilities to employ most efficient ways of electrical energy delivery from generation to distribution infrastructures. For bulk power transfer over long distances improved transmission efficiency is a primary target to ensure less electrical energy losses and costs. The application of conventional HVDC schemes at 500 kV DC […]

Seeing through switchgear

  Radiographic inspection saves costs and downtime and enables better maintenance planning. Ever since its discovery almost 120 years ago, radiography has both been both a source of fascination and a valuable tool. The stark and almost spooky grayscale photographs of our bones that we see in the hospital provide an unparalleled insight into the insides […]

Connecting a PV system to the grid and how to earth it

  A key constraint to the implementation of grid-connected small-scale renewable energy activities in South Africa is the lack of pre-approved, generic standards for utility engineers and system promoters to apply in designing and approving the utility interface. This article covers part two of the recommended wiring procedure for the NRS097-2-1:2010 standard which is available […]

Water blocking in MV XLPE cables

  The penetration of water or the presence of moisture in XLPE cables is one of the most serious problems associated with the lifespan of cables under the influence of high electrical stresses. XLPE insulated cables which are designed to operate at 600 to 1000 V require insulation thicknesses well above those required purely for […]

Power cable systems: The ideal underground power solution

  As South Africa develops, more and more electric power is needed to electrify domestic homes as well as to meet the ever-increasing demand for more power by the mining, industrial and commercial sectors in existing and newly developed areas around the country’s cities. This demand requires not just more power stations, but also more […]

Twenty-first century distribution transformers

  William Stanley, working for Westinghouse is credited for building the first refined and commercially used transformer. In 1886 he used his transformers in the electrification of Great Barrington, Massachusetts, USA. This was the first ever implementation of an AC power distribution system using step up and step down transformers. Today, more than 120 years […]

Case study: Fire in an underground 33 kV XLPE cable splice

  An underground mine was evacuated after a fault occurred involving the three-phase and ground on the 33 kV overhead line on the mine surface. While the initial fault cleared quickly, it appears to have led to a so-called “cross country fault” in the 33 kV reticulation system. Over the next six minutes a failure […]

Voltage and var support in electric power systems

  The present environment for the operation of electric power systems (EPS) is complicated by environmental, economic as well as societal constraints. As a result EPS operate often close to their limits while trying to minimise costs and keep the quality of supply according to standards. The picture is complicated further by new types of […]

Emerging geospatial tools for the electrical grid

  Since the genesis of widespread electricity distribution in the 1880s, there has always been a need for geospatial information to help manage the grid. The electrical system is inherently spatial in nature, rooted in the geography of the service territory. This is true whether the territory is an entire country served by a national […]