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The aim of this paper is to investigate m –isometric composition operators on directed graphs with one circuit. We establish a characterization of m –isometries and prove that complete hyperexpansivity coincides with 2–isometricity within this class. We discuss the m –isometric completion problem for unilateral weighted shifts and for composition o...
Use of Weather Information for Secure, Reliable and economic Operation of Indian Grid
Citations
... Bai et al. [22] confirmed also the decrement of (from 1.30 to 1.27 at 1 Sun) for increasing cell temperatures (an increment of around 12 K) for monofacial PERC cells. This fact is also confirmed by [23]. ...
... There is a clear positive correlation for crystalline silicon. This finding is in line with some earlier papers [2,3,6,21,23,44]. Contrary, other authors [14,19,43,56] have reported a decrement of for increasing values of , also for the same technology. ...
... According to these results, for none of the technologies under study it is possible to derive a dependence of the shunt resistance ℎ with respect the temperature. However, there are few papers in the literature that contradict this conclusion [2,14,23,41,43,79]. A possible reason is that the authors of those studies consider a range of temperature (for example from +10 • C until +70 • C) that is significantly wider than the ones used in this paper. ...
... In this paper, improvements have been made to the MPPT hill-climbing control, playing on its speed and accuracy. This enhancement is based on the optimal electrical characteristics (voltage, current) of PV panels [25][26][27][28][29]. While guaranteeing the continuous stability of the entire system without divergence, regardless of unexpected weather or load variations, special attention is paid to accuracy when searching for the MPP. ...
This article implements maximum power point tracking (MPPT) based on the improved hill-climbing algorithm for photovoltaic (PV) systems feeding resistive loads. A direct current-to-direct current boost converter is inserted between the PV system and the load to achieve matching. The converter is managed using MPPT based on the hill-climbing algorithm. The objective of this paper is to optimize the code program to achieve the best compromise between accuracy and rapidity by implementing this algorithm using a microcontroller. Two PV systems are tested under identical meteorological conditions. In the first, an improved hill-climbing MPPT controller is used whereas, in the second, the conventional version is employed. The experimental results obtained show a significant enhancement in terms of speed for the improved algorithm with a value of 0.4 s for the response time and 3% for the oscillation power; those values remain satisfactory in terms of precision of the algorithm compared with the conventional system studied and the compared algorithm from the literature.
... Governments and private enterprises are collaborating to implement policies and incentives aimed at encouraging the deployment of these clean technologies [12,13]. Renewable energy projects also contribute to reducing greenhouse gas emissions, making Africa a key player in the global fight against climate change [10,14,15]. Furthermore, these projects serve as a vital engine for economic development, empowering local communities, and preserving the environment [6,16]. ...
... Through its commitment to renewable energies, Africa is shaping a sustainable energy future for its inhabitants and becoming an inspiring example for the rest of the world [17]. The African continent, rich in natural resources, is not only an exceptional laboratory for innovation in renewable energies but also a fertile ground for exploring sustainable energy models tailored to local needs [15]. Research in this field has the potential to radically transform African energy systems, creating jobs, stimulating economic development, and improving energy access for millions of people [10-12, 14, 18]. ...
This paper presents a bibliometric analysis of scientific research on renewable energy in Africa, a rapidly growing field driven by the need for sustainable and accessible energy solutions. It highlights Africa's role as a hub for renewable energy innovation, with local researchers collaborating with global institutions to address the continent's unique energy challenges. This synergy is enhancing energy access in African communities and contributing to the global advancement of renewable technologies. The study meticulously examines 3,109 scientific publications from the Scopus database, spanning from 1979 to 2022. It analyzes the evolution, geographical distribution, and impact of these publications, with a focus on international collaborations and scientific output. Findings indicate that South Africa leads in productivity with 962 publications and hosts the top affiliating institutions in this domain. The study also reveals an exponential increase in renewable energy research, particularly from South Africa, the United States, and the United Kingdom, emphasizing the need for more collaborative efforts and knowledge exchange globally. This analysis provides critical insights into the current landscape of renewable energy research and pinpoints areas ripe for further exploration and development in this vital sector.
... The influence of internal parameters such as photogenerated current, reverse saturation current, and ideality factor distinguishes the performance of one PV cell from another. The parasitic resistances of the PV cell are involved in the calculations, causing power losses in practical PV modules [9]- [11]. A good PV cell must have a small series resistance and a large parallel resistance value to approach ideal conditions. ...
Partial shading (PS) has a significant impact on the decrease in efficiency of photovoltaic (PV) array and performance of maximum power point tracking (MPPT) that must be addressed. We conduct an analysis and evaluation of local maximum power point (LMPP) in terms of quantity, and global maximum power point (GMPP) in terms of magnitude and diversity. Simulation is carried out using single diode ideal model and nine generic PS patterns that are specifically designed to bring up the substantial characteristics of the LMPP and GMPP and applied to series-parallel (SP) and total cross-tied (TCT) configurations. The SP configuration has LMPP with two, three, and four peaks, appearing three times each. The TCT configuration has two peaks that appear six times, three peaks that appear once, and four peaks that appear twice. The SP configuration experiences power losses ranging from 56% to 72%, while the TCT configuration has power losses ranging from 52% to 64%. The SP configuration generates a maximum voltage of 76.64 volts and a minimum of 39.20 volts, while the TCT configuration generates a maximum voltage of 77.62 volts and a minimum of 58.21 volts. With a smaller number of LMPP, a larger magnitude of GMPP parameters, and lower diversity, TCT exhibits better characteristics and performance compared to SP.
... The results show that a higher percentage of modules under hot and humid climatic conditions suffer from metallization corrosion compared to other zones. Bounouar et al. [12] have assessed the impact of an increase in the module operating temperature on the various component of R s in the PV module. Herein, for a 6% power dissipation due to R s in the module, the contribution of four components namely, finger resistance, busbar resistance, base resistance, and emitter resistance, is accounted for about 75%, 12%, 7%, and 3%, respectively. ...
Degradation modes affecting series resistance
(Rdeg,modes) are one of the major causes of performance
degradation in outdoor operating photovoltaic (PV) modules.
They have distinct loss incurring mechanisms under different
climatic conditions. In this article, major Rdeg,modes have been
investigated for their impact on the electrical parameters and
differentiated based on their distinct electrical signatures at both
cell and module levels. For this purpose, the major Rdeg,modes
have been identified through cross-characterization of nine unaged
PV modules subjected to temperature cycle, humidity freeze, and
damp heat test conditions, using electroluminescence imaging and visual inspection. These Rdeg,modes have been broadly categorized as metallization interruption, metallization corrosion, and cracks with loss in the active cell area. The spatial characteristics of various Rdeg,modes have been modeled using distributed diode model of a solar cell, which has been experimentally validated. The change in fill factor has been chosen as a base metric to compare various Rdeg,modes. The results show that combined case of metallization interruptions can be more severe than metallization corrosion. The maximum loss in power of up to 40% has been calculated for interruption at the finger-busbar interface. Furthermore, based on the loss incurring mechanism, various Rdeg,modes exhibited distinct electrical signatures that were analyzed using normalized percentage change in voltage and current at the maximum power point, which has also been used to distinguish them. The distinct electrical signatures can be used for identification and nondestructive investigation of Rdeg,modes in the PV modules under field-operating conditions.
... Simultaneously, wind and solar energy conversion do not have an exhaust thermal energy component for energy conversion [3]. Increasing self-consumption in microgrids is essential for reducing grid losses and securing 'rotating reserves' in the transmission network [4,5]. ...
Modern residential buildings are not often equipped with independent energy sources such as wind generators, PV panels or similar sources from which green energy is generated. Experts predict that prosumers who concurrently produce and consume electricity will soon emerge en masse. Due to fluctuating and intermittent renewable energy sources, this dual process can increase the burden on the electricity grid. In this article, a process simulation of the energy supply of a residential building is developed, with PV panels as the independent source of electricity. The studied parameters of the prosumer nanogrid are a non-shiftable electrical load graph, and a separate load graph of warm water consumption with a battery that ensures the need for energy from the non-shifting load graph. For the annual simulation, we use measurement data with an average interval of 5 minutes. The article models and simulates energy flow graphs that will depend on consumption and production schedules and the size and design of storage devices, such as a buffer battery between the nanogrid and utility grid. If we double PV production compared total consumption and buffer battery 10 kWh together , we get the whole cover factor for the resultant increase Δ = 0.139. It means that the increment is 23 % in relative units. The novelty of the work is the use of a buffer battery between nano-and utility grids to increase the own consumption of PV electricity. One of the outputs of the article is the comparison of the same nanogrid configuration with the wind generator instead of the PV panels as a local energy source. The results show that PV panels require significantly lower battery and water heater volumes than a wind generator to achieve the same demand cover factor. Compared to the power generation of PV panels with the wind generator, the inverter's power can be reduced to half the capacity without significantly reducing the demand cover factor. Nomenclature LMI-Load Matching Index LGMI-Load Generation Matching Index PV-PV panels NG-nanogrid UG-utility grid BB-buffer battery SB-nanogrid storage battery BO-hot water consumption in kWh YD-the demand cover factor W1-the sum of the annual production of PV, which is at first hand consumed by NS needs W2-the sum of the annual production of PV, which is used for BO from WH W3-the sum of the annual production of PV used for the NS consumption pattern from the battery annually W4-the energy that moves back from BB to NG. If there is not enough eModern residential buildings are not often equipped with independent energy sources such as wind generators, PV
panels or similar sources from which green energy is generated. Experts predict that prosumers who concurrently produce and consume electricity will soon emerge en masse. Due to fluctuating and intermittent renewable energy sources, this dual process
can increase the burden on the electricity grid. In this article, a process simulation of the energy supply of a residential building is developed, with PV panels as the independent source of electricity. The studied parameters of the prosumer nanogrid are a non-shiftable electrical load graph, and a separate load graph of warm water consumption with a battery that ensures the need for energy from the non-shifting load graph. For the annual simulation, we use measurement data with an average interval of 5 minutes. The article models and simulates energy flow graphs that will depend on consumption and production schedules and the size and design of storage devices, such as a buffer battery between the nanogrid and utility grid. If we double PV production compared total consumption and buffer battery 10 kWh together , we get the whole cover factor for the resultant increase Δ = 0.139. It means that the increment is 23 % in relative units. The novelty of the work is the use of a buffer battery between nano- and utility grids to increase the own consumption of PV electricity. One of the outputs of the article is the
comparison of the same nanogrid configuration with the wind generator instead of the PV panels as a local energy source. The results show that PV panels require significantly lower battery and water heater volumes than a wind generator to achieve the
same demand cover factor. Compared to the power generation of PV panels with the wind generator, the inverter's power can be reduced to half the capacity without significantly reducing the demand cover factor.
