The question of why all electric transmission and distribution circuits cannot be run underground to avoid the visual and other effects is often posed. The main argument against constructing underground systems is usually financial. But costs are not the only limitation. The basic laws of electricity limit how physically long an underground cable can be. […]
While directional earth fault also uses the concept of a relay characteristic angle to determine direction, it looks at a different vector value to conventional overcurrent: the zero sequence component. In this article, we explain some of the concepts behind directional earth fault, sharing our experience to support field deployment of this valuable protection element. […]
Rooftop-mounted photovoltaic systems (RTPV) are expected to have a dramatic impact on distribution networks, and concern has been expressed on the effect on distribution transformers (DT), as increased thermal cycling is expected. However, several diverse studies have shown that a reasonable penetration of RTPV can extend the lifetime of a DT. Nonetheless, if the penetration increases […]
Distributed generation, which is an emerging technological trend around the world, poses a new set of challenges for the energy industry. With the real possibility of bi-directional power flow and the erosion of the conventional generation, transmission, distribution, retail sequence, the inevitable outcome is that distribution networks need to handle network protection in both forward […]
Modern electrical installations supply power to a wide variety of non-linear loads, where the current drawn does not have a linear relationship with the voltage supplied. This results in distortions in the current and voltage waveforms. The degree of distortion in these waveforms tends to increase according to the number of non-linear loads in a […]
RWW recently achieved full grid code compliance for harmonic emissions on two solar PV plants located in the Western Cape. The practical implications of obtaining PQ compliance for two “category C” photovoltaic (PV) renewable power plants (RPP) are described in this article. The plants were non-compliant with regards to current harmonic emissions as per the latest […]
Microgrids using renewable energy, with their promise of economically generated electricity and a high level of security are a powerful incentive for their integration in today’s distribution networks, more so as the renewable asset base for domestic, industrial and commercial uses continues to increase. There is good reason to believe that new ventures concentrating on […]
Electrical power is essential. From the time when our alarm goes off in the morning to when we turn the lights off at night, we use electrical power. In terms of magnitude, each person in the US spends around $3052 on electricity (2012 figures). With a population of about 314-million people at the time, our […]
Electricity supply in Africa has consistently been provided by state-owned electricity enterprises for over a hundred years. Electricity distribution is usually undertaken by large vertically-integrated government-controlled utilities, except in very few cases. This article provides an analysis of global experiences in the privatisation of electricity distribution and considerations for its application in an African context. There is […]
Lightning damage to specific electronic components supported by large electrodes raised questions that led to an initially hypothesised damage mechanism associated with the components. This article outlines the anticipated damage mechanism and presents the background that contributed to the hypothesis. In addition, the particular conditions that present challenges in mitigating against the damage is addressed. […]
