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Results in Journal Smart Grid and Renewable Energy: 343

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Abdourahimoun Daouda, Sani Idi Boubabacar, Moctar Mossi Idrissa, Saidou Madougou
Smart Grid and Renewable Energy, Volume 12, pp 53-63; doi:10.4236/sgre.2021.124004

Abstract:
Today, energy is a vital component in the functioning of a hospital. Hospital technical facilities have several types of technologies, these include appliances for use; examination apparatus. So, for Quality Health Care in a hospital, there is a need to ensure the proper functioning of hospital equipment. In addition to the required maintenance as specified by the device manufacturer, the quality of the electrical energy across the device must be ensured. This article is an analysis of the quality of electric energy at the substation of National Hospital of Niamey. Thereby, the data collection, followed by the data processing and analysis revealed the parameters characterizing the quality of electrical energy across the substation. Our studies have shown that the substation is underutilized as the maximum inrush current is less than half the available current. The current was consumed by the three phases has resulted in a strong current unbalance (230 A). However, the current unbalance and the voltage amplitude, are admissible accordingly base on EN50160 standard. Furthermore, the harmonics voltages present in this medium are in the accepted range (1.8%) according to IEEE 519 standard. However, the fundamental frequency does not meet the standard, but the difference obtained has no adverse effect.
Husain Alsamamra, Iyad Isaila, Jawad Shoqeir
Smart Grid and Renewable Energy, Volume 12, pp 17-29; doi:10.4236/sgre.2021.122002

Abstract:
Energy demand overall the world increases rapidly in various sectors, one of the highest energy consumption sector is the building sector. Installation of PV systems is one of the solutions to cover this demand and will serve in promoting energy efficiency in the Palestinian municipalities in decreasing the electricity bill, and using the saved money in constructing new projects and improving the level of services provided to citizens. In this work, Al-Dahriya municipality has been taken as a case study. The municipality installed 20 KW of photovoltaic panels on the roof of the main building in 2015. The cumulative values for one year after installation the PV system represent a total consumed electricity by the main building was 71,506 kw, while the total generated power by the PV system that transferred to building was 32,664 kw, and 5323 kw exported to the grid with total generated power by PV system was 37,987 kw. The participation of energy that produced by the photovoltaic system is 53.12% of the total power demand of the building. The value of generated power varies between the summer months and winter months through the difference of the solar radiation intensity and the number of shinning hours, the largest reading of solar radiation intensity is in the summer months. The study ensures the importance of applying selected thermal insulation materials in order to decrease the heat transfer through the boundary wall of the building. Furthermore, this study covers the other buildings and utilities of municipality and recommended with certain issues in order to promote energy efficiency.
Chenyuhu Yang
Smart Grid and Renewable Energy, Volume 12, pp 1-15; doi:10.4236/sgre.2021.121001

Abstract:
Faced with the exhaustion of traditional energy sources, the development of new energy devices is the current priority. Supercapacitor is a new type of energy storage device with high power density and long cycle life. Carbon material, metal oxide and conductive polymer are three common electrode materials of supercapacitors. Based on China’s energy situation, this paper puts forward new ideas from coal to graphene to supercapacitors. In addition, the research progress of graphene supercapacitors is summarized, including the principle of supercapacitors, preparation methods from coal to graphene, graphene electrode materials and different modification, and some possible scientific problems in the research process of different modified graphene electrodes are also reviewed and prospected.
Sameer Khader, Abdel-Karim Daud
Smart Grid and Renewable Energy, Volume 12, pp 31-52; doi:10.4236/sgre.2021.123003

Abstract:
This paper investigates the behaviors of Boost DC Chopper used in Photovoltaic energy systems where the solar irradiation changes during the day time causing current and voltage changes. Varying the solar irradiation causes output chopper voltage changes in order to keep working at maximum extracted solar power. The chopper voltage changes leading to variable duty cycle operation of chopper switch and causes a significant change in switch losses in terms of the dissipated power. In addition to that the chopper behaviors are studied when the chopper voltage is boosting up to a predetermined reference value leading to a significant change in chopper current, voltage, duty cycle and occurred losses. A mathematical model for chopper performances and switch losses is derived, and a simulation model using Matlab/ Simulink platforms is conducted to follow the chopper behaviors. Simulation results for concreteSUNPOWER panel type SPR-315E-WHT-D with 315 Watts peak indicates that during the daylight time transistors are exposed to complicated changes in their current, voltage and dissipated power. Furthermore changing the output voltage according to load requirements causes heavy stress on the transistor in terms of current, oscillations and losses as well. Simulation results show that there are optimized values of irradiation, chopper voltage and duty cycle where the transistor losses are minimized. In addition to that, projecting the transistor losses over the daylight time at a given irradiation rate shows how these losses vary among the year, and the amount of energy dissipated across the main chopper switch which is around 2970 Whr/yr for the present case. Furthermore, the conducted simulation also shows the occurred in the transistor behaviors when solar irradiation changes, and can be serving for further studies.
Hans Grassmann, Marco Citossi, Renato Bernes, Andrea Piani
Smart Grid and Renewable Energy, Volume 11, pp 21-28; doi:10.4236/sgre.2020.112002

Abstract:
Solar energy as well as biomass energy techniques suffers from disadvantages, which in some cases limit their potential for substituting fossil fuels. For instance, solar energy is difficult to store, and many kinds of biomass are not suited for combustion, in spite of the fact that they have high energy contents. We describe and industrial size system, which has the goal of overcoming some of these limitations by combining solar- and biomass power. This is achieved by roasting residual biomass by means of hot air provided by solar power only. The solar power is collected by three “Linear Mirror” solar concentrator, they are designed to achieve high efficiency also at northern latitudes. Each one is equipped with an innovative solar-air heat exchanger. The hot air is delivered to a roasting device filled with humid residual biomass. We report the performance of this system from a first commissioning run. The system is intended to help create a closed-cycle economy by means of transforming waste biomasses to a high-quality combustible.
Raguilignaba Sam, Alain Diasso, Bernard Zouma, François Zougmoré
Smart Grid and Renewable Energy, Volume 11, pp 191-200; doi:10.4236/sgre.2020.1112012

Abstract:
A theoretical study of a polysilicon solar cell with a radial junction in static regime under monochromatic illumination is presented in this paper. The junction radial solar cell geometry is illustrated and described. The carriers’ diffusion equation is established and solved under quasi-neutral base assumption with boundaries conditions and Bessel equations. New analytical expressions of electrons and holes photocurrent density and quantum efficiency are found. The wavelength and structural parameters (base radius, base thickness and wavelength) influences on photocurrent density and quantum efficiency are carried out and examined.
Mahamadi Savadogo, Boubacar Soro, Ramatou Konate, Idrissa Sourabié, Martial Zoungrana, Issa Zerbo, Dieudonné Joseph Bathiebo
Smart Grid and Renewable Energy, Volume 11, pp 61-72; doi:10.4236/sgre.2020.115005

Abstract:
It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (CPV). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (MPP) moves to the open circuit when the cell temperature increases.
Atushi Umemura, Rion Takahashi, Junji Tamura
Smart Grid and Renewable Energy, Volume 11, pp 1-20; doi:10.4236/sgre.2020.111001

Abstract:
In recent years, power generation using renewable energy sources has been increasing as a solution to the global warning problem. Wind power generation can generate electricity day and night, and it is relatively more efficient among the renewable energy sources. The penetration level of variable-speed wind turbines continues to increase. The interconnected wind turbines, however, have no inertia and no synchronous power. Such devices can have a serious impact on the transient stability of the power grid system. One solution to stabilize such grid with renewable energy sources is to provide emulated inertia and synchronizing power. We have proposed an optimal design method of current control for virtual synchronous generators. This paper proposes an optimal control method that can follow the virtual generator model under constrains. As a result, it is shown that the proposed system can suppress the peak of the output of semiconductor device under instantaneous output voltage drop.
Laura Giménez De Urtasun, David M. Rivas-Ascaso, Noemi Galán Hernández, Giorgos Papadoupoulos, Kostas Tsatsakis
Smart Grid and Renewable Energy, Volume 11, pp 29-49; doi:10.4236/sgre.2020.113003

Abstract:
Most of the isolated electrical systems throughout the world suffer from similar problems of fragility and high dependence on external resources to generate energy. Smart Grid solutions and integration of renewable energies in order to solve their problems have increased, although it is necessary to know their specific characteristics to select the optimal solutions for each case. Therefore, as the overall objective of INSULAE Project, the development of an Investment Planning Tool, IPT, is on the way. This paper provides a view on a characterization methodology developed for the set of Reference Islands and how it will help to exploit the IPT developed. For that, characterization vectors have been defined based on a selection of Key Performance Indicators (KPIs). And Reference Islands have been obtained from the analysis of KPIs data gathered from EU islands considering the vectors formed. The linkage of new islands to reference islands helps provide the new islands with an assessment on the possibility space of their investment plans with the aim of being a decarbonization plan considering the demonstrations already evaluated.
M. Koilraj Gnanadason, P. Senthil Kumar, Vincent H. Wilson
Smart Grid and Renewable Energy, Volume 11, pp 73-87; doi:10.4236/sgre.2020.116006

Abstract:
The demand of fresh water is becoming an increasingly important issue across the world. To alleviate this problem, a single slope single basin solar still was designed and tested. Top glass cover 9° slope ensures a very good transmission of solar radiation inside the still. In this paper a review of factors that improve the performance of the still is presented. Energy balances are made for each element of the still; solar time, direction of beam of radiation, clear sky radiation, optical properties of the cover, convection outside the still, convection and evaporation inside are accounted. Theoretical analysis of the heat and mass transfer mechanisms inside the solar still has been developed to find out heat transfer coefficients such as internal and external heat transfer modes and thermo physical properties such as dynamic viscosity, density, thermal conductivity, latent heat of evaporation and saturated vapor pressure for passive solar distillation system. Heat transfer coefficients were estimated for the present system since the still efficiency depends on heat transfer modes. It is also suggested that the water temperature plays a vital role in the distillate output since it increases significantly with the rise of basin water temperature. It is also found that the rise in water temperature increases the evaporative heat transfer coefficient value significantly.
Edwin Khethiwe, Ketlogetswe Clever, Gandure Jerekias
Smart Grid and Renewable Energy, Volume 11, pp 165-180; doi:10.4236/sgre.2020.1110010

Abstract:
In the efforts to reduce effects of climate change, biodiesel fuels from plant oils such as Jatropha curcas have been proposed as alternative fuels which can be used in the transportation sector in diesel engines. The current study investigates the effects of fatty acids composition on fuel properties of biodiesel derived from Jatropha curcas seeds obtained from selected regions of Botswana. The physicochemical fuel properties investigated include kinematic viscosity, flash point, energy content, density, pour point and cloud point from derived Jatropha curcas biodiesel. Results of the study showed that Jatropha curcas biodiesel samples for all regions under review are dominated by unsaturated fatty acids which are desirable for cold flow properties and kinematic viscosity of the biodiesel fuel. The major fatty acids in Jatropha curcas biodiesel fuels from all the regions range from 69.00% to 77.81% of unsaturated fatty acids. The overall results conclude that fatty acids composition has influence on the fuel properties of the biodiesel under investigated.
Alain Diasso, Raguilignaba Sam, Bernard Zouma, François Zougmoré
Smart Grid and Renewable Energy, Volume 11, pp 181-190; doi:10.4236/sgre.2020.1111011

Abstract:
This manuscript presents a simple method for excess minority carriers’ lifetime measurement within the base region of p-n junction polycrystalline solar cell in transient mode. This work is an experimental transient 3-Dimensionnal study. The magnitude of the magnetic field B is varied from 0 mT to 0.045 mT. Indeed, the solar cell is illuminated by a stroboscopic flash with air mass 1.5 and under magnetic field in transient state. The experimental details are assumed in a figure. The procedure is outlined by the Open Circuit Voltage Decay analysis. Effective minority carrier life-time is calculated by fitting the linear zone of the transient voltage decay curve because linear decay is an ideal decay. The kaleidagraph software permits access to the slope of the curve which is inversely proportional to the lifetime. The external magnetic effects on minority carriers’ effective lifetime is then presented and analyzed. The analysis shows that the charge carrier’s effective lifetime decrease with the magnetic field increase.
Ibrahim M. Kadad, Kandil M. Kandil, Talal H. Alzanki
Smart Grid and Renewable Energy, Volume 11, pp 103-125; doi:10.4236/sgre.2020.118008

Abstract:
This study examines the correlation between solar UVB and different weather parameters in Kuwait climate. To achieve that purpose, an experimental outdoor facility is designed and set up at the College of Technological Studies, Kuwait for regular monitoring of solar global radiation, UVB radiation and ambient temperature in Kuwait from beginning of January 1st 2014 until the end of December 2019. Outcomes reveal that the change of solar UVB as well as global radiation through the whole day inaugurate the same behavior for the recorded data in clear day times. Statistical analysis is carried out to obtain a correlation linking UVB radiation and both ambient temperature and global solar radiation. Regression analysis of the current work shows that there is a solid correlation among UVB radiation and both ambient temperature and global solar radiation, especially for intermediate to small global solar radiation ranges. In addition, UV index is evaluated for various months at all day times. It is important to record that UV index with the maximum values is attained in May-August months through midday period. Also, UV index values do not surpass the accepted extreme value which is higher than 9 during any time of the study period.
D. Soro, M. Sidibé, Y. Doumbia, S. Touré, B. Marí
Smart Grid and Renewable Energy, Volume 11, pp 51-60; doi:10.4236/sgre.2020.114004

Abstract:
A box-type solar cooker with an inclined surface, equipped with a concentration reflector to allow maximum energy to be collected, enabled cooking tests to be carried out in the rainy season. Different thermocouples were implanted on various places of the cooker. The temperature measurements from these sensors were taken every 10 minutes. The tests presented in this article relate to the preparation of eggs and rice. The absorber temperatures during the tests exceeded 100°C. The cooking times were between 1 h 50 min and 2 h 20 min despite the numerous cloudy periods. The cooker made it possible to reach sufficient temperatures for healthy cooking of food. The results obtained for these first tests are satisfactory and very encouraging.
Dieudonné Kaoga Kidmo, Bachirou Bogno, Kodji Deli, Deli Goron
Smart Grid and Renewable Energy, Volume 11, pp 127-164; doi:10.4236/sgre.2020.119009

Abstract:
This study aimed at investigating the characteristics of the wind power resource in the Far North Region of Cameroon (FNR), based on modelling of daily long-term satellite-derived data (2005-2020) and in-situ wind measurements data (1987-2020). Five different reliable statistical indicators assessed the accuracy level for the goodness-of-fit tests of satellite-derived data. The two-parameter Weibull distribution function using the energy factor method described the statistical distribution of wind speed and investigated the characteristics of the wind power resource. Six 10-kW pitch-controlled wind turbines (WT) evaluated the power output, energy and water produced. A 50 m pumping head was considered to estimate seasonal variations of volumetric flow rates and costs of water produced. The results revealed that the wind resource in FNR is suitable only for wind pumping applications. Based on the hydraulic requirements for wind pumps, mechanical wind pumping system can be the most cost-effective option of wind pumping technologies in FNR. However, based on the estimated capacity factors of selected WT, wind electric pumping system can be acceptable for only four out of twenty-one sites in FNR.
Dialo Diop, Mamadou Simina Drame, Moussa Diallo, David Malec, Dominique Mary, Philippe Guillot
Smart Grid and Renewable Energy, Volume 11, pp 89-102; doi:10.4236/sgre.2020.117007

Abstract:
This study aims to evaluate the optical losses of photovoltaic modules due to Saharan dust deposition in Dakar, Senegal, West Africa. For this purpose, an air-dust-glass system is modeled to simulate optical losses in transmittance and reflectance. To do this, we have collected dust samples from Photo-Voltaic (PV) surface in Dakar area (14°42'N latitude, 17°28'W longitude), Senegal. X-ray fluorescence reveals that silicon (Si), iron (Fe), calcium (Ca) and potassium (K) mainly composed these dust samples. Then, dust refractive indices obtained from an ellipsometer were used as an input to be used in the model. Simulations show that for radiation (at normal incidence) arriving on a dust layer of 30 μm-thick (corresponding to a dust deposit of 1.63 g/m2), 79% of the visible spectrum is transmitted; 19% is reflected and 2% is absorbed. Overall, the transmittance decreases by more than 50% as of dust layer of 70 μm-thick corresponding to a dust deposit of 3.3 g/m2.
Mohamed Elmamy Mohamed Mahmoud, Soukeyna, A. Yahfdhou, A. K. Mahmoud, I. Youm
Smart Grid and Renewable Energy, Volume 10, pp 17-28; doi:10.4236/sgre.2019.102002

Abstract:
The use of renewable energy is growing significantly in the world. In front of the growing demand for electric energy, essentially for the needs of remote, isolated and mountainous regions, photovoltaic systems, especially water pumping systems, are beginning to emerge in large applications. In this sense, the proposed study deals with the problem of the water level regulation in the photovoltaic pumping system. It is in this context that the interest in this paper is dictated by the need to use an existing energy source on the site. Still in this light, it is important to note that, often, the calculation of the size of the GPV that feeds the pumping system and the pump involves a certain degree of uncertainty, mainly due to two main reasons: the first is related to randomness of solar radiation which is often little known and the second is related to the difficulty to estimate the water needs. This is why, on the one hand, the realization of such a system has made it possible to show the possibility of determining the projected quantity for water storage. Similarly, it has shown that the prediction of this quantity of water can be calculated by a simple analytical method based on numerical computation. Thus, it was also shown for this pumping system, thanks to graphical analysis methods, developing autonomy, reliability and good performance. In this sense, this experience opens the door for a practical and economical solution to the problem of lack of water, especially in our regions. Measurements made on the studied system prove that the designed approach improves the efficiency. Finally, it is also expected to draw further conclusions for the operation of these systems in similar sites.
Kandil M. Kandil, Talal H. Alzanki, Ibrahim M. Kadad
Smart Grid and Renewable Energy, Volume 10, pp 119-140; doi:10.4236/sgre.2019.105008

Abstract:
This work investigates the performance of combined hybrid high concentrated photovoltaic/thermal collector (HCPV/T) in Kuwait harsh climate. The proposed system consists of triple junction solar cells (InGaP/InGaAs/Ge) attached to heat source to discharge thermal energy to cooling media. Published HCPV/T models do not consider the effect of shunt resistance which greatly affects the system performance. So, a single diode model employing five parameters including the effect of shunt resistance is adapted to analyze the proposed system. To analyze the thermal performance of the proposed system, a two-dimensional thermal model based on the technique of finite difference is introduced to determine the efficiency of the hybrid HCPV/T system. The present developed subroutines are integrated with other involved codes in TRNSYS software to calculate HCPV/T system efficiency. Electrical and thermal as well as the whole system efficiency at different weather circumstances are evaluated and assessed. The effect of different weather conditions, cell temperature, concentration ratio and the temperatures of the coolant fluid on system performance are studied. Current results indicate that the model of single diode is a reliable one rather than using the two-diode complex model. Compared to measurements provided by high concentrated PV manufacturer, the current results revealed a total root mean square error of approximately 1.94%. Present predictions show that PV cell temperature has logarithmic increase with the rise in concentration ratio but with low values till concentration ratio of 400 suns after that the rise is faster at higher concentration values up to 1500 suns. Results also revealed that hybrid HCPV/T system works effectively specially in severe hot climate where thermal efficiency increases with high surrounding temperature for higher values of concentration ratio. In addition, an increase of approximately 15% in thermal efficiency and 10% in total efficiency can be achieved by utilizing active cooling device in HCPV/T system.
Mamunur Rashid, Nazmus Shakib, Tamjidur Rahman
Smart Grid and Renewable Energy, Volume 10, pp 203-212; doi:10.4236/sgre.2019.108013

Abstract:
The purpose of this research is to optimize biogas production from POME by using anaerobic reactor with various Organic Loading Rate, Carbon-Nitrogen ratio and Hydraulic Retention Time. For conducting this research, a two-stage fermentation anaerobic bioreactor has used at OLR rate1, 2.6, 5, 9 and 11 g/L.d; at C/N ratio 14.54, 20, 28, 36, 41.454; at HRT 2.295, 4, 6.5, 9, 10.70 days. The anaerobic bioreactor is operated for 30 days. The finding of this research demonstrates the optimum input values are OLR is 5 (g/L.d), C/N is 28, HRT is 6.5 days and output of Biogas is 3.8 L/d from POME. This finding will bring benefits to palm oil industries in achieving economic and environmental sustainability. This research concludes that in-depth research into this matter is important to implement this technology in the palm oil industry.
Drissa Boro, Hagninou Elagnon Venance Donnou, Imbga Kossi, Nebon Bado, Florent P. Kieno, Joseph Bathiebo
Smart Grid and Renewable Energy, Volume 10, pp 257-278; doi:10.4236/sgre.2019.1011016

Abstract:
This study investigates both the characteristics of the vertical wind profile at the Bobo Dioulasso site located in the Sudanian climate zone in Burkina Faso during a day and night convective wind cycle and the estimation and variability of the wind resource. Wind data at 10 m above ground level and satellite data at 50 m altitude in the atmospheric boundary layer were used for the period going from January 2006 to December 2016. Based on Monin-Obukhov theory, the logarithmic law and the power law made it possible to characterize the wind profile. On the study site, the atmosphere is generally unstable from 10:00 to 18:00 and stable during the other periods of the day. Wind extrapolation models were tested on our study site. Fitting equations proposed are always in agreement with the data, contrary to other models assessed. Based on these equations, the profile of a day and night cycle wind cycle was established by extrapolation of wind data measured at 10 m above the ground. Lastly, the model of the power law based on the stability was used to generate data on wind speed from 20 m to 50 m based on data from 10 m above the ground. Weibull function was used to characterize wind speed rate distribution and to calculate wind energy potential. The average annual power density on the site is estimated at 53.13 W/m2 at 20 m and at 84.05 W/m2 at 50 m, or 36.78% increase. Considering these results, the Bobo-Dioulasso site could be appropriate to build small and medium-size turbines to supply the rural communities of the Bobo Dioulasso region with electricity.
Gabriel Vasco, Jones S. Silva, Fausto A. Canales, Alexandre Beluco, , Elton G. Rossini
Smart Grid and Renewable Energy, Volume 10, pp 83-97; doi:10.4236/sgre.2019.104006

Abstract:
Seasonal variability coupled with the intermittency of renewable energy sources makes reservoir hydroelectric plants an interesting option to consider in hybrid energy systems, especially in cases of dams that have not been completed or have been abandoned and which still have some potential for reuse. The Laranjeiras dam was completed in the 1960s and the original project for hydroelectric power generation was not completed, made impossible by economic changes during the construction years. A recent study proposed the implementation of a hydroelectric photovoltaic hybrid system with lower horsepower to allow the dam to be made useful again. This paper presents the results of the computational simulations with the software Homer, considering the operation of the hydroelectric component (of the proposed hybrid system) with reservoir, playing the role of energy storage device when the production exceeds the demand at a given moment, reducing the loss of energy due to unavailability of demand. The study suggested to implement a hydroelectric power plant with power house at the base of the dam that has a height of 20 m, operating at a minimum flow of 9171 L/s, with reservoir operating as a device for energy storage, operating with a photovoltaic system of 360 kW, and a power limit for the purchase of energy from the grid equal to 200 kW, providing consumer loads up to 40 MWh per day, with cost of energy equal to US$0.021 per kWh and a capital cost of US$3285.617.
Mehdi Moradian, Milad Moradian
Smart Grid and Renewable Energy, Volume 10, pp 29-41; doi:10.4236/sgre.2019.102003

Abstract:
In this paper, simulation and implementation way for practical control of Single Inverter Microgrid (SIMG) is presented. This system is equipped by solar system, wind energy conversion system (WECS), and microturbine system. Each DG’s has controlled independently. This is a kind of decentralize control because each DG’s has difference controller. Control of Microgrid (MG) during both grid tie and islanding modes is presented. Solar system and WECS are modeled based on santerno products. This system is compared with three inverter MGs with Centralize control strategy. Controlled signals show that SIMG is more reliable and economical. THD is improved and strategy is simplified for SIMG.
Kota Kawasaki, Keiichi Okajima
Smart Grid and Renewable Energy, Volume 10, pp 1-15; doi:10.4236/sgre.2019.101001

Abstract:
In this paper, a method to detect a decrease in the output power of photovoltaic systems is proposed. This method is based on using satellite irradiance data. In addition, fault detection is carried out with only one day’s data in this method. Thus, the time elapses since the decrease in output is shorter than with the other methods. In order to mitigate the error in satellite data and improve the accuracy of fault detection, data extraction is carried out, which consists of two steps. In the first step, effective data are extracted by setting a lower irradiance limit. In the second step, “Calculation day” is determined depending on the number of effective data in one day. Fault detection, which is only conducted on the Calculation day, is conducted by comparing the expected power and the measured power. The parameters used in this study were optimized by testing 45 systems that appear normal. Subsequently, 340 systems were analyzed with the proposed method, using optimized parameters. The results showed the effectiveness of our method from the viewpoints of both accuracy and time required. In addition, three data extraction methods were considered to distinguish between the permanent decrease caused by failure, and the temporary decrease caused by partial shade. Fuzzy cluster analysis showed the best result among the three methods used.
Nikolas M. Katsoulakos
Smart Grid and Renewable Energy, Volume 10, pp 55-82; doi:10.4236/sgre.2019.104005

Abstract:
Among the Greek islands, 61 are based—currently—on autonomous electrical systems for covering the electrical energy demand and are characterized as Non-Interconnected Islands (NII). The average electricity production cost in the NII is 2.5 times higher than in areas with access to the main, interconnected electricity grid (IEG) of Greece. In this paper, an analytic overview of the autonomous electricity systems of Greek islands is provided, focusing on electricity consumption and production, as well as on the relative costs. For investigating possibilities for improving the situation, especially in small, remote islands, simulations for the energy system of Astypalea are conducted. It is proved that further use of renewables in combination with energy storage can lower the current, high energy costs. Expansion of the IEG is not economically viable for islands which are far away from the mainland and their peak loads are less than 10 ΜW.
Talal H. Alzanki, Kandil M. Kandil
Smart Grid and Renewable Energy, Volume 10, pp 237-256; doi:10.4236/sgre.2019.1010015

Abstract:
Energy consumption in buildings is considered a significant portion of gross power dissipation, so a great effort is required to design efficient construction. In severe hot weather conditions as Kuwait, energy required for building cooling and heating results in a huge energy loads and consumption and accordingly high emission rates of carbon dioxide. So, the main purpose of the current work is to convert the existing institutional building to near net-zero energy building (nNZEB) or into a net-zero energy building (NZEB). A combination of integrated high concentrated photovoltaic (HCPV) solar modules and evacuated tube collectors (ETC) are proposed to provide domestic water heating, electricity load as well as cooling consumption of an institutional facility. An equivalent circuit model for single diode is implemented to evaluate triple junction HCPV modules efficiency considering concentration level and temperature effects. A code compatible with TRNSYS subroutines is introduced to optimize evacuated tube collector efficiency. The developed models are validated through comparison with experimental data available from literature. The efficiency of integrated HCPV-ETC unit is optimized by varying the different system parameters. Transient simulation program (TRNSYS) is adapted to determine the performance of various parts of HCPV-ETC system. Furthermore, a theoretical code is introduced to evaluate the environmental effects of the proposed building when integrated with renewable energy systems. The integrated HCPV-ETC fully satisfies the energy required for building lighting and equipment. Utilizing HCPV modules of orientation 25? accomplishes a minimum energy payback time of about 8 years. Integrated solar absorption chiller provides about 64% of the annual air conditioning consumption needed for the studied building. The energy payback period (EPT) or solar cooling system is about 18 years which is significantly larger than that corresponding to HCPV due to the extra expenses of solar absorption system. The life cycle savings (LCS) of solar cooling absorption system is approximately $2400/year. Furthermore, levelized cost of energy of solar absorption cooling is $0.21/kWh. Hence, the net cost of the solar system after subtracting the CO2 emission cost will be close to the present price of conventional generation in Kuwait (about $0.17/kWh). Finally, the yearly CO2 emission avoided is approximately 543 ton verifying the environmental benefits of integrated HCPV-ETC arrangements in Kuwait.
Saka Goni, Haroun Ali Adannou, Dialo Diop, Adoum Kriga, Ahamoud Youssouf Khayal, Bado Nebon, Aboubaker Cheidikh Beye, Serigne Abdoul Aziz Niang, Mamadou S. Drame
Smart Grid and Renewable Energy, Volume 10, pp 165-178; doi:10.4236/sgre.2019.106011

Hussein Ibrahim, Mohamad Issa, Richard Lepage, Adrian Ilinca, Jean Perron
Smart Grid and Renewable Energy, Volume 10, pp 213-236; doi:10.4236/sgre.2019.109014

Abstract:
Supercharging is the process of supplying air for combustion at a pressure greater than that achieved by natural or atmospheric induction, as applied to internal combustion engines. As a consequence of demonstrated technological, economical and energetic advantages in multiple literature evaluations concerning the large scale wind-compressed air hybrid storage system with gas turbines, the utilization of a hybrid wind-diesel system with compressed air storage (HWDCAS) has been frequently explored. These will mainly have average or small scale application such as the powering of isolated sites. It has been proven in numerous studies that the HWDCAS combined with an additional supercharging of the diesel engines will contribute to the increase of the power and efficiency of the diesel engine, the reduction of both fuel consumption and the emission of greenhouse gases (GHG). This article presents the obtained results from experimental validation of the selected design with an aim to valorize this innovative solution and become trustworthy.
Ehab H. E. Bayoumi
Smart Grid and Renewable Energy, Volume 10, pp 141-154; doi:10.4236/sgre.2019.105009

Abstract:
The Phase Locked Loop controller parameters are the key-point that affects the dynamic performance of the autonomous microgrid. They have to be optimally tuned to guarantee enhanced overall system stability. In this paper, two-microgrid plant with their associate PWM inverter connected to the ac main grid and the load is used as an example to demonstrate the capabilities of the proposed system. The Phase Locked Loop controller is designed and tuned using the Simulating Annealing algorithm. This algorithm is used to select the Phase Locked Loop PI controller gains with optimal percentage overshoot, rise time and settling time. The controller is tested during the transition between grid-connected and autonomous operation and in reverse order. The controller is compared with Ziegler and Nichols P and PI controllers. It shows the effectiveness and the extraordinary control response of the proposed control technique with respect to percentage overshoot, rise time and settling time control parameters compared to the conventional one.
Hans Grassmann, Marco Citossi
Smart Grid and Renewable Energy, Volume 10, pp 155-164; doi:10.4236/sgre.2019.105010

Abstract:
The Linear Mirror II is an innovative system to concentrate solar energy, developed by Isomorph SRL. In this paper, a solar-air heat exchanger of new conception is presented and tested together with a Linear Mirror II. The heat exchanger surface is selective with respect to direction and position of light absorption and emission and once heated by the Linear Mirror II, can reach an air temperature of up to 230°C.
Manzar Ahmed, Asif Nawaz, Mishaal Ahmed, Muhammad Shoaib Farooq
Smart Grid and Renewable Energy, Volume 10, pp 43-53; doi:10.4236/sgre.2019.103004

Abstract:
In this paper, Nanogrid System and working is presented for the future sustainable power system. This system is for small scale for smart homes with decentralized power system. A Nanogrid is the combination of energy system such as using of sources such as solar cells, fuel cells, micro turbines, wind turbines, energy storage devices and AC, DC power systems and controllable loads. This grid may use single mode or island mode with soft switching. The Dynamic of power system capability increases reliability, in case if one system fails it switch to other system to continue proving electric power with losing quality. The energy storage system is used to maintain stability during transition between the operating modes is emphasized. The Simulink model is used to present the working of system.
Mohammed Mousa, Sherif Abdelwahed, Joni Kluss
Smart Grid and Renewable Energy, Volume 10, pp 98-117; doi:10.4236/sgre.2019.104007

Abstract:
Fault management study in smart grid systems (SGSs) is important to ensure the stability of the system. Also, it is important to know the major types of power failures for the effective operation of the SGS. This paper reviews diverse types of faults that might appear in the SGS and gives a survey about the impact of renewable energy resources (RERs) on the behavior of the system. Moreover, this paper offers different fault detection and localization techniques that can be used for SGSs. Furthermore, a potential fault management case study is proposed in this paper. The SGS model in this paper is investigated using both of the Matlab/Simulink and the Real Time Digital Simulation (RTDS) to compute the fault management study. Simulation results show the fast response to a power failure in the system which improves the stability of the SGS.
Muhammad Raisul Alam, Marc St-Hilaire, Thomas Kunz
Smart Grid and Renewable Energy, Volume 10, pp 179-202; doi:10.4236/sgre.2019.107012

Abstract:
This research addresses the planning and scheduling problem in and among the smart homes in a community microgrid. We develop a bi-linear algorithm, named ECO-Trade to generate the near-optimal schedules of the households’ loads, storage and energy sources. The algorithm also facilitates Peer-to-Peer (P2P) energy trading among the smart homes in a community microgrid. However, P2P trading potentially results in an unfair cost distribution among the participating households. To the best of our knowledge, the ECO-Trade algorithm is the first near-optimal cost optimization algorithm which considers the unfair cost distribution problem for a Demand Side Management (DSM) system coordinated with P2P energy trading. It also solves the time complexity problem of our previously proposed optimal model. Our results show that the solution time of the ECO-Trade algorithm is mostly less than a minute. It also shows that 97% of the solutions generated by the ECO-Trade algorithm are optimal solutions. Furthermore, we analyze the solutions and identify that the algorithm sometimes gets trapped at a local minimum because it alternately sets the microgrid price and quantity as constants. Finally, we describe the reasons of the cost increase by a local minimum and analyze its impact on cost optimization.
Akira Nishimura, Syota Tanikaga, Masafumi Hirota, Eric Hu
Smart Grid and Renewable Energy, Volume 09, pp 57-73; doi:10.4236/sgre.2018.94005

Abstract:
An integrated energy system (with photovoltaic (PV) and fuel cell (FC) for building) is proposed and assessed in term of its energy self-sufficiency rate in seven cities (Nagoya, Toyota, Tajimi, Takayama, Ogaki, Hamamatsu, Shizuoka) in Tokai region in Japan in this paper. In this work, it is considered that the electricity requirement of the building for household users is provided by a building integrated photovoltaic (BIPV) system and the gap between the energy demand and BIPV supply is fulfilled by the FC. The FC is powered by the electrolytic H2 produced when PV power was in surplus. Based on the study of applying the proposed system in seven cities, which clarifies the effectiveness of the integrated BIPV, electrolytic H2 and FC power generation system, a universal system model has been developed in this paper. It has been observed that the monthly power production from BIPV as well as FC system are higher in spring and summer, while they are both lower in autumn and winter at all considered locations. The self-sufficiency rate of the FC system is higher with decreasing households’ number and it has been observed that 16 is the most appropriate number of households in a building, whose electricity demand could be fully covered by the integrated PV and FC system. Due to its climate condition, Hamamatsu is the best city in the region for installing the proposed system. The correlation between the households’ number and self-sufficiency rate of the FC system per solar PV installation area can be expressed by the regression curve in the form of y = ax-b well.
Jordy Charly Isidore Rabetanetiarimanana, Mamy Harimisa Radanielina, Hery Tiana Rakotondramiarana
Smart Grid and Renewable Energy, Volume 09, pp 171-185; doi:10.4236/sgre.2018.910011

Abstract:
Rural electrification remains a great challenge for Sub-Saharan Africa (SSA) as access to electricity is a prerequisite to accelerate its development. The present paper reviews the measures adopted to promote access to electricity in rural and remote areas of SSA. The main barriers to rural electrification in these developing countries are presented before showing technologies used for the aforementioned purpose. Then, adopted methods for enhancing the use of renewable energy in SSA are shown. Moreover, the policy adopted by decision makers and project planners are also highlighted. In addition, the optimal solutions proposed by researchers are given such as the cost-effective off-grid system type that might be a viable alternative to diesel power generation.
, Adrian Will, Jorge Gotay, Sebastián Rodríguez
Smart Grid and Renewable Energy, Volume 09, pp 151-170; doi:10.4236/sgre.2018.99010

Abstract:
Currently, the electrical system in Argentina is working at its maximum capacity, decreasing the margin between the installed power and demanded consumption, and drastically reducing the service life of transformer substations due to overload (since the margin for summer peaks is small). The advent of the Smart Grids allows electricity distribution companies to apply data analysis techniques to manage resources more efficiently at different levels (avoiding damages, better contingency management, maintenance planning, etc.). The Smart Grids in Argentina progresses slowly due to the high costs involved. In this context, the estimation of the lifespan reduction of distribution transformers is a key tool to efficiently manage human and material resources, maximizing the lifetime of this equipment. Despite the current state of the smart grids, the electricity distribution companies can implement it using the available data. Thermal models provide guidelines for lifespan estimation, but the adjustment to particular conditions, brands, or material quality is done by adjusting parameters. In this work we propose a method to adjust the parameters of a thermal model using Genetic Algorithms, comparing the estimation values of top-oil temperature with measurements from 315 kVA distribution transformers, located in the province of Tucumán, Argentina. The results show that, despite limited data availability, the adjusted model is suitable to implement a transformer monitoring system.
Amy LeBar, Heather E. Dillon
Smart Grid and Renewable Energy, Volume 09, pp 259-271; doi:10.4236/sgre.2018.912016

Abstract:
A hybrid solar collector was designed to investigate the effects of combining two different solar collector techniques on the overall collector’s effectiveness. While most solar collectors focus only on one solar collection method, the small hybrid system uses a flat plate collector in conjunction with five evacuated tubes to absorb the most energy possible from both direct and diffuse solar radiation. Data was collected over four months while the system operated at different flow rates and with various levels of available insolation from the sun to evaluate the performance of the solar collector. To understand the relative contribution of the flat plate collector and the evacuated tubes, temperature differences across each part of the system were measured. The results indicate the average first law efficiency of the hybrid system is 43.3%, significantly higher than the performance of the flat plate alone. An exergy analysis was performed for this system to assess the performance of the flat plate system by itself. Results of the second law analysis were comparable to the exergetic efficiencies of other experimental collectors, around 4%. Though the efficiencies were in the expected range, they reveal that further improvements to the system are possible.
Nicholas Nixon Opiyo
Smart Grid and Renewable Energy, Volume 09, pp 75-99; doi:10.4236/sgre.2018.95006

Abstract:
Impacts of grid architectures on temporal diffusion of PV-based communal grids (community owned minigrids or microgrids) in a rural developing community are modelled and simulated using MATLAB/Simulink and a survey-informed agent-based model (ABM) developed in NetLogo. Results show that decentralised control architectures stimulate minigrid formations and connections by allowing easy expansions of the minigrids as each decentralised PV system within a minigrid is treated equally and determines its own real and reactive power, eliminating the need for communication links. This also reduces the cost of implementing such a system; fewer connections are realized with centralised controls as such systems require high speed communication links which make them both difficult to expand and expensive to implement. Results also show that multi-master operation modes lead to more communal grid connections compared to single-master operation modes because in the former, all distributed PV systems within a communal grid have the same rank and can act as masters or can be operated as combinations of master generators (VSIs) and PQ inverters, allowing for more design flexibility and easy connections from potential customers.
Yassir Idris Abdalla Osman, Jinping Li, Xiaofei Zhen
Smart Grid and Renewable Energy, Volume 09, pp 113-125; doi:10.4236/sgre.2018.97008

Abstract:
House-hold PV panels are widely used; however, their performance is significantly degraded under real operating conditions. Environmental factors such as ambient temperature, wind speed, and solar irradiance has a major impact on the house-hold PV panel efficiency. In this paper an experimental study was conducted during the winter period in a single building in Minqin county, Gansu province, China. The experimental measurements were used to quantify the house-hold PV panel performance and operating characteristics. Based on the experimental results the house-hold PV panel performance is basically affected by the PV surface temperature, therefore, multilevel of energy is detected. Approximately 3% efficiency variation is detected due to the impact of the environmental factors.
Talal H. Alzanki, Kandil M. Kandil, , Adel A. Ghoneim
Smart Grid and Renewable Energy, Volume 09, pp 237-258; doi:10.4236/sgre.2018.911015

Abstract:
High concentrated PV multi-junction solar cells (HCPV) likely present a favorable alternative to achieve low cost of energy. However, multi-junction solar cell has different characteristics which should be settled before they can be adapted for large scale energy generation. Peak energy consumption in Kuwait usually occurs in periods of utilizing air conditioning systems which are essentially used in almost all year around in harsh climate like Kuwait. Power consumed at peak times is more costly than power needed to satisfy loads at regular consumption times. The main goal of the present research is to increase HCPV solar cells’ efficiency, to decrease maximum power cost in Kuwait. Multi-junction solar cells performance in weather conditions of Kuwait is investigated employing a single diode equivalent circuit model. The model developed considers the impacts of concentration ratio as well as temperature. Most research in literature review usually neglects shunt resistance of the diode, however this resistance is taken into consideration in current developed theoretical model. To calibrate the present model, current predictions are compared with corresponding measured data provided by multi-junction solar cell manufacturer. The total root mean square errors in the present model predictions are about 1.8%. This means that current developed model of single diode model which takes into account shunt resistance impacts gives precise and reliable data. HCP electrical efficiency is noticed to rise as concentration increases but to a certain concentration value, then it begins to decrease. In addition, utilizing HCPV linked to grid satisfies great decrease in maximum load. Power produced from HCPV modules is utilized to provide energy needs to a family in normal Kuwaiti family home to evaluate HCPV environmental effects. HCPV modules slopes and areas are changed to accomplish peak energy production all over the year. Present results reveal that optimum power production corresponds to HCPV modules directed to south and having latitude of 25°. In addition, employing HCPV modules can avoid approximately 1.55 ton of emitted CO2 per year. In conclusion, current work reveals the advantage impacts of grid connected HCPV in Kuwait weather.
Byungtae Jang, Alidu Abubakari, Namdae Kim
Smart Grid and Renewable Energy, Volume 09, pp 215-236; doi:10.4236/sgre.2018.910014

Abstract:
Globally, traditional power systems are rapidly transforming towards the adoption of smart grid platforms. Substations which are at the center of the electric power transformation from the power plant are changing to IEC 61850 based digital substations. Therefore, within substation, there is a growing demand for the IEC 61850 based Intelligent Electronic Devices (IEDs). The operation of multiple manufacturers of IEDs in a single digital substation network increases the need for IEC 61850 communications specification conformance diagnosis to ensure interoperability for efficient data exchange between IEDs. The IEC 61850-10 presents test items for diagnosing communication specification conformance. There are many test tools available in the market today to test the compliance of the IEC 61850 communications specifications to the IED. In this paper, we propose a model-based diagnostic method for IED communication conformance testing. The proposed model-based software therefore uses the “drag and drop” technique to select the various IEC 61850 communication services (objects) required to design the test case in a user friendly Graphical User Interface (GUI). This makes the service conformance testing more flexible for test engineers and system integrators especially in situations that require test case modifications. Also, the proposed software tool makes it easy to understand the various IEC 61850 services using the friendly GUI.
Byungtae Jang, Alidu Abubakari, Namdae Kim
Smart Grid and Renewable Energy, Volume 09, pp 127-149; doi:10.4236/sgre.2018.98009

Abstract:
The IEC 61850 standard stipulates the Substation Configuration Description Language (SCL) file as a means to define the substation equipment, IED function and also the communication mechanism for the substation area network. The SCL is an eXtensible Markup Language (XML) based file which helps to describe the configuration of the substation Intelligent Electronic Devices (IED) including their associated functions. The SCL file is also configured to contain all IED capabilities including data model which is structured into objects for easy descriptive modeling. The effective functioning of this SCL file relies on appropriate validation techniques which check the data model for errors due to non-conformity to the IEC 61850 standard. In this research, we extend the conventional SCL validation algorithm to develop a more advanced validator which can validate the standard data model using the Unified Modeling Language (UML). By using the Rule-based SCL validation tool, we implement validation test cases for a more comprehensive understanding of the various validation functionalities. It can be observed from the algorithm and the various implemented test cases that the proposed validation tool can improve SCL information validation and also help automation engineers to comprehend the IEC 61850 substation system architecture.
Hani Albalawi
Smart Grid and Renewable Energy, Volume 09, pp 33-41; doi:10.4236/sgre.2018.92003

Abstract:
In recent years, high annual increasing load demand in Saudi Arabia has led to large investments in the construction of conventional power plants, which use oil or gas as the main fuel. The government is considering a large deployment of renewable energy for its 2030 vision plan. The Kingdom of Saudi Arabia is one of the best potential candidates for harvesting solar energy because of the country’s geographical location, clear sky, and vast land area. A recent energy policy announced by the government involves harvesting solar photovoltaic (PV) energy to reduce the country’s reliance on fossil fuel and greenhouse gas emissions. Using rooftop PV systems can help to shave the peak load and lead to a significant savings in the power sector through the reduction of annual installation of conventional power plants and standby generators. Employing solar PV at the end user level helps to reduce the overloading of transmission and distribution lines as well as decreases power losses. This paper will provide ratings for different rooftop PV systems that are being considered for installation for customers with various needs. The distribution of PV installation among the customers is as follows: 5% residential, 10% commercial, and 20% government. The effect of PV output power on weekly peak demand has been evaluated. The paper has also investigated the impact of the temperature on PV output power, especially during the summer. The PV power contribution is analyzed based on the assumption that weekly peak power production of solar PV coincides with weekly peak load demand. The PV model is implemented in Matlab to simulate and analyze the PV power.
Yassir Idris Abdalla Osman, Jinping Li, Xiaofei Zhen, Airong Yang
Smart Grid and Renewable Energy, Volume 09, pp 1-15; doi:10.4236/sgre.2018.91001

Abstract:
In recent years, PV panels witnessed a vigorous gross, as their performance and the leverage of large-scale industrial production steadily decreased costs. Factors such as solar irradiance, insolation, mismatch of modules/arrays characteristic, aging, partial shading situation have a major effect on the harvested power. Evidence suggests that partial shading situation is the most critical factor and causes a significant reduction in PV system output. In this paper, a method based on two degrees of freedom, namely upper and lower was proposed in order to address the partial shading losses that due to cloud movement. Moreover, an extensive simulation of voltage, current indicators, bypassed modules, fault string, and DC output power was presented to analyze the PV system. The validation of experimental data analysis was carried out on two different days with different amounts of solar irradiance in Minqin County, Gansu Province, China. The results indicated that the power losses were 18.989 W and 127.629 W according to the minimum and the maximum irradiations (1.88 MW/m2) and (2.104 MW/m2) respectively. By considering the minimum irradiance, the upper and the lower degrees of freedom of the losses were 22.17 W/d, and 15.8 W/d respectively. On the other hand, by considering the maximum irradiance, the upper and the lower degrees of freedom were 130.49 W/d, 125.78 W/d respectively.
Daniel Ngondya, Joseph Mwangoka
Smart Grid and Renewable Energy, Volume 09, pp 16-31; doi:10.4236/sgre.2018.91002

Abstract:
Increasing consumption, changing nature of loads and the need to reduce carbon emission are some of the factors threatening electricity grid stability and reliability. Demand side management programs mainly work by shifting consumption from peak to off-peak period, which inconveniences some consumers and possibly creates a new peak (Reverse Peak) in off-peak hours. Growing use of Photovoltaic solar power in residences provides an opportunity to manage grid reliability and stability in a more flexible manner, and mitigates reverse peaks. We propose a community based scheduling algorithm that guarantees access to shared power capacity and integrates residences’ solar power into the grid. Results indicate peak demand can be reduced by up to 32.1%, while energy costs can be reduced by up to 14.0%. Furthermore, coordinated discharging can mitigate reverse peaks by up to 23.4%. Encouraging and integrating green energy generation and storage in the consumer side is crucial to grid stability and reliability.
Serigne Ndiangue Leye, Ibrahima Fall, Senghane Mbodji, Papa Lat Tabara Sow, Gregoire Sissoko
Smart Grid and Renewable Energy, Volume 09, pp 43-56; doi:10.4236/sgre.2018.93004

Abstract:
We report the study of the temperature dependance of the performance electronic parameters of an N-P solar cell by considering as model, the columnar cylindrical orientation associated to the dynamic junction velocity (SF) concept. We presented the photocurrent-photovoltage (I-V) and Power-photovoltage (P-V) characteristic curves. The short-circuit photocurrent (Isc), the open circuit photovoltage (Uoc), the fill factor (FF) and the efficiency (η) are linearly dependent on the temperature. The temperature coefficients (T-coefficient) relative to the short-circuit, open-circuit photovoltage and efficiency are calculated and the comparison with data from the literature showed the accuracy of the considered model.
Namdae Kim, Alidu Abubakari, Byungtae Jang
Smart Grid and Renewable Energy, Volume 09, pp 186-198; doi:10.4236/sgre.2018.910012

Abstract:
The digital substation system consists of an Intelligent Electronic Device (IED) which requires information for the supervision, protection, and control, as well as a client operating system for substation operation. IEC 61850 communication standard has been defined for information exchange between heterogeneous digital devices in such substations. Currently, the Korea Electric Power Corporation (KEPCO) digital substation system uses unbuffered reporting and Generic Object Oriented Substation Events (GOOSE) communication functions for monitoring, protection and control automation. However, it is expected that the Setting Group function will be needed to operate adaptive intelligent substation system. The Setting Group function is advantageous in that it is possible to change the setting of the IED in one unified way through the client operating system, rather than changing the correction value of an IED through different manufacturer-based engineering tools. In order to utilize the Setting Group function of the IED in real substation scenario, it is necessary to test both the communication function with the host operating device and the electric functional test to ensure that correction value is properly changed. In this paper, we introduce the IEC 61850 Setting Group function, and propose a method that can integrate communication function and electrical function test of an IED conforming to the setting group functionality. We also tested the Setting Group function of the actual IED device through the proposed integrated functional test method and analyzed the results. We were able to simplify the process of testing both the electrical and communication signals in digital substations.
Yahya Z. Alharthi, ,
Smart Grid and Renewable Energy, Volume 09, pp 199-214; doi:10.4236/sgre.2018.910013

Abstract:
This paper presents a study aimed at evaluating and comparing the performance of six different tracking systems for photovoltaic (PV) with diesel-battery hybrid system in arid climate of Kingdom of Saudi Arabia (KSA). The study considered various technical and economic factors including system net present cost (NPC), levelized cost of energy (LCOE), and PV power generation using energy analysis and microgrid design software “HOMER”. It also presents an overview of the current electricity production and demand in the Kingdom. The weather data used in this study have been collected from the new solar atlas launched by King Abdullah City for Atomic and Renewable Energy (KACARE). The selected solar resource monitoring station for this study is located near to Riyadh city and has an annual average daily total irradiation of 6300 W/m2/day. The study shows that, for stand-alone PV system in the vicinity of Riyadh city, tracking system is economically better than fixed angle system. Among the considered tracking systems, VCA system is the most preferable as it has low NPC and LCOE values with a high return on investment (ROI) as well as low carbon dioxide (CO2) emissions due to a high renewable energy penetration.
, Geoffrey John, , Samwel Manyele,
Smart Grid and Renewable Energy, Volume 09, pp 272-284; doi:10.4236/sgre.2018.912017

Abstract:
The study of non-isothermal kinetics analyzed the reactivity of pine sawdust, while the thermodynamic properties analyzed energy consumed and released from the pine sawdust. The kinetic parameters were determined by analyzing mass loss of pine sawdust components by using Thermogravimeric analyzer. The cellulose has the highest conversion rate of 9.5%/min at 610 K compared to hemicellulose and lignin, which are 5%/min at 600 K and 2%/min at 800 K, respectively. The activation Energy for cellulose, hemicellulose and lignin was 457.644, 259.876, and 89.950 kJ/mol, respectively. The thermodynamic properties included the change of Gibbs free energy for cellulose and hemicellulose, which were -214.440 and -30.825 kJ/mol respectively, their degradation was spontaneous in forward direction, while change of Gibbs free energy for lignin was 207.507 kJ/mol, which is non-spontaneous reaction. The positive value of change of entropies for the active complex compounds formed from hemicellulose and cellulose is less stable, while the active complex compounds of lignin are characterized by a much higher degree of arrangement since its change of entropy is negative. The kinetic and thermodynamic properties show that pine sawdust is a good candidate for production of char since it is easier to remove hemicellulose through thermal process.
Adama Ouedraogo, Serge Dimitri Y. B. Bazyomo, Salifou Ouedraogo, Abdoul Razakou,
Smart Grid and Renewable Energy, Volume 09, pp 285-298; doi:10.4236/sgre.2018.912018

Abstract:
This manuscript is about a theoretical modelling of conversion efficiency improvement of a typical polycrystalline Si solar cell in 1D assumptions. The improvement is brought by the increase of the collection of the minority carriers charge in excess. This increase is the consequence of the influence of an electric field provided by the use of the open circuit photovoltage of another silicon solar cell. We assume that it is integrated two silicon solar cells to the system. The first solar cell provides the open circuit photovoltage which is connected to two aluminum planar armatures creating a planar capacitor. The second solar cell is placed under the uniform electric field created between the two aluminum armatures. This work has shown an improvement of the output electric power leading to the increase of the conversion efficiency. We observe an increase of 0.7% of the conversion efficiency of the second silicon solar cell.
Nicholas Nixon Opiyo
Smart Grid and Renewable Energy, Volume 09, pp 101-112; doi:10.4236/sgre.2018.96007

Abstract:
Different droop control methods for PV-based communal grid networks (minigrids and microgrids) with different line resistances (R) and impedances (X) are modelled and simulated in MATLAB to determine the most efficient control method for a given network. Results show that active power-frequency (P-f) droop control method is the most efficient for low voltage transmission networks with low X/R ratios while reactive power-voltage (Q-V) droop control method is the most efficient for systems with high X/R ratios. For systems with complex line resistances and impedances, i.e. near unity X/R ratios, P-f or Q-V droop methods cannot individually efficiently regulate line voltage and frequency. For such systems, P-Q-f droop control method, where both active and reactive power could be used to control PCC voltage via shunt-connected inverters, is determined to be the most efficient control method. Results also show that shunt-connection of inverters leads to improved power flow control of interconnected communal grids by allowing feeder voltage regulation, load reactive power support, reactive power management between feeders, and improved overall system performance against dynamic disturbances.
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