A non-intrusive network impedance measurement setup, aimed at live mains networks, is proposed. The system is able to measure in both time- and frequency domain, and links the measured impedance to the phase of the mains voltage signal. The method is based on the transmission parameters of the injecting and receiving probes. This paper covers the theory behind transmission parameters, a characterization method for current transformers, the measurement setup- and algorithm, and a discussion of its results by means of analysis and recommendations.
The EN 50561-3, a power line communication standard, has been published. It allows very high interference levels, and is neglecting the allocation of the very high frequency band 30 MHz-87.5 MHz, which is mainly assigned to military communication. It is shown that these communication systems are severely degraded, in our experiment a reduction of performance of 44 dB was measured. The military personal who are, especially after recent terrorist attacks and the following lockdowns, active in our cities to safeguard the citizens are dependant of the use of the very high frequency communication systems, and they will be very seriously hampered when using then communication systems. It is shown that the EN 50561-3 and the power line communication systems are violating the essential requirements of the European EMC Directive.
Despite the concerted efforts to provide electricity through the deployment of distributed renewable energy-based technologies, the sustainability of these infrastructures remains uncertain. One plausible explanation is the inadequate operation and maintenance strategy throughout the system's lifetime. This paper describes the progress of rural electrification to address electrification challenges in remote rural areas and the failures that occurred. Data on the operational status of several off-grid solar systems in various countries are presented. The most recent reports on the subject were reviewed and critical sustainability concerns surrounding the topic were assessed. The paper concludes with an argument that while technology is a main ingredient in achieving universal energy access, there are nontechnical aspects to consider to ensure the sustainability of the technology.
Energy Access in sub-Saharan Africa is a gaining interest in both academic research and industrial development. This paper analyzes how power electronics, EMC, philosophy and social sciences are intersected within this topic, and proposes topics for further research within these complex dynamics.
Solar home systems are a prevalent method to enter the electrification ladder, and may gain even more popularity as the load diversity increases, or when they can be adopted into projects in which they can be extended into larger electrical networks. DC power quality needs to be regarded if such future perspectives are to become a durable reality. This paper discusses the need for power quality in solar home systems, proposes a methodology for researching it, and illustrates potential issues for solar home systems by an example.
This paper presents the comparisons between time-domain voltage and current measurement techniques for interference analysis in Power Line Communication (PLC) application. Voltage measurement is performed by directly sensing the mains voltage from a speed-controlled water pump using a 1:1000 voltage divider, whilst the current is measured using three types of sensors: current clamp, hall element, and differential probe over a shunt resistor. Voltage and current from these sensors are read with a digital oscilloscope. Impedance and power are calculated as well using post-processing software, in which the results can be analyzed in the frequency domain using a spectrogram to observe the possibility of performing communication. Voltage and current transducers should have transfer functions which are independent of frequency when performing time-domain measurements.
Increasing the life cycle of battery packs is one of the most valuable endeavors in modern Li-ion battery technologies, especially for light electric vehicles whose material costs are often significantly determined by the costs of the battery pack. The main aim of the present study is to help manufactureres of LEV's to circumvent the type of discharge profiles that substantially degrade the LEV's battery pack. To this end, this paper describes a measurement setup in which various discharge patterns from light electric vehicles, acquired during actual use of the vehicles, are simulated in a lab environment in order to assess their influence on the degradation of the Li-ion battery packs. The results of these measurements can be used to optimize discharge profiles and improve battery management systems with the aim to extend the Li-ion battery life time.
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