Reducing blackouts through power stability control

  China has one of the most complex interconnected HVAC and HVDC power grids in the world. All of the regional grids of China have implemented NR Electric’s Power Stability Control System (PSCS), which has dramatically improved the stability of the grids. The performance has been demonstrated, most visibly, in the reduction of blackouts, but […]

Assessing the effect of PV generation on distribution system voltages

  Utility distribution systems have seen a huge increase in distributed energy resources (DER) in recent years not only due to renewable portfolio standard requirements but also government financial support. Furthermore, it is becoming much more common for DER generation levels to significantly exceed the local load on the feeder to which it will be […]

South Africa: Electricity pricing paralysing the poor

  The electricity sector in South Africa has been in a state of disruption over the last few years. The country’s power utility company, Eskom, has been under scrutiny for several reasons. Most of these reasons relate to the rolling blackouts, load-shedding episodes of 2007/8 and high levels of inefficiency. Constant tariff increases under the […]

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 […]