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Problem-based learning has proven to develop teamwork, problem solving skills, communication and critical thinking skills amongst learners. Due to these advantages, secondary schools in South Africa engage with problem-based events to promote the participation of learners in Science, Technology, Engineering and Mathematics (STEM). However, many schools face lack of time, lack of available funds and...
A wide range of modern low voltage power electronic (PE) devices feature sophisticated controls, which aim to improve device performance and ensure better regulation of grid-side ac currents. The implementation of these controls is expected to result in increased device efficiency, improved controllability, higher operating power factors and reduced harmonic emissions. The interactions of individual...
We describe a simple method for making in-house, low concentration (0–100ppm) pressed pellet standards for analyzing Ni, Cu, Mo, V and U in carbonate lithologies by wavelength dispersive X-ray fluorescence (WD-XRF) spectrometry. This method can easily be modified to include other elements of interest and to encompass a different range of concentrations. The purpose here was to circumvent the general...
Voltage quality plays an important role in modern distribution networks. One voltage quality parameter is harmonic distortion. Voltage harmonics in MV-networks are measured in most cases by using installed inductive voltage transformers (IVT). The accuracy of these transformers for frequencies above nominal frequency (50Hz or 60Hz) is usually not known. The paper presents a systematic analysis of...
Nowadays power quality, especially voltage quality becomes more and more important for utilities, manufacturers and customers as well as for the regulatory authorities. Therefore a growing number of voltage quality monitoring campaigns with continuously increasing measurement times, considerably longer than one week, are observed. The assessment of voltage quality according to common standards (e...
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