Power and Energy System Engineering

Nigeria's electricity sector continues to experience chronic shortages despite abundant natural resources. This study assesses the spatial potential of onshore wind energy across Nigeria through integrated Geographic Information Systems (GIS) and Multi-Criteria Decision Analysis (MCDA). Hourly wind data from NASA POWER and ERA5 reanalysis were extrapolated to 150 m hub height and combined with topographic, land cover, and socio-environmental datasets to evaluate national wind suitability. The analysis reveals a pronounced north-south gradient in wind resources, with the northern regions exhibiting higher mean wind speeds and more favorable topography for large-scale wind power development. Using the Analytical Hierarchy Process (AHP), suitability was classified into three categories (Most Preferred, Preferred, and Least Preferred) based on wind potential, land-use conflicts, and population pressure. The Most Preferred zone, covering approximately 18 % of Nigeria's land area, lies predominantly in the northern savanna belt, offering the greatest opportunity for utility-scale deployment. The resulting spatial classification provides a strategic framework for targeted wind energy investment and forms a foundation for subsequent techno-economic and policy assessments.

This paper present optimal power flow and short circuit analysis of an IEEE-14 bus system using the Electrical Transient Analyzer program (ETAP) software. The load flow and short circuit studies in power system are very important for both design and operating stage performance evaluation, as well as ensuring dependable grid operations through appropriate protection scheme settings. In addition, comparison between load flow analysis and its optimal load flow analysis, then the short circuit evaluations are carried out It is employed to determine the greatest and lowest fault currents for 3-phase and single-line to ground faults on different buses. Inductive loads that connect to the electrical system generally consume reactive power. Load flow analysis is used to calculate the voltage, the real power, and also the reactive power flow over each bus. Optimal power flow analysis is frequently used to reduce a system's fuel expenditures by minimizing actual and reactive power losses. In order to calculate protective device ratings, the IEEE-14 bus system uses maximum and minimum short circuit currents, also known as sub-transient and steady state fault currents

The integration of distributed generation (DG) sources into distribution systems has experienced significant growth due to their numerous advantages. However, DG integration has also introduced substantial challenges to distribution system protection, such as variations in fault current levels and bidirectional fault current flow. Under these conditions, directional overcurrent relays may not operate as intended. This paper proposes a directional comparison protection scheme for safeguarding lines and zones in active distribution systems, based on the calculation of incremental active power transient energy. Additionally, a differential protection scheme, based on the Teager-Kaiser Energy Operator (TKEO), is incorporated to enhance the performance of the directional identification algorithm. The proposed scheme is capable of detecting symmetric and unsymmetric faults on microgrid lines at both low and medium voltage levels and is adaptable to changes in microgrid configurations and load-switching transients. The proposed methods offer the advantages of simplicity in calculation and high accuracy. An AC active distribution system incorporating inverter-based DG sources is modeled in PSCAD-EMTDC software to simulate various fault types, and the simulation results are subsequently transferred to MATLAB for the implementation of the proposed algorithms.

Regular power outages in Maiduguri, Nigeria, resulting from vandalism and old transmission infrastructure, undermine the electricity supply to critical institution. The paper presents a design and techno-economic analysis of a grid-solar photovoltaic (PV) hybrid energy system for the Senate Complex, University of Maiduguri. Based on site-specific solar resource, actual load profiles, and HOMER Pro simulations, the system was sized with 791 PV modules (700 Wp each), a 4570.71 Ah battery bank and a 248kW inverter for an annual demand of 528.74 MWh. Technical and economic parameters involved in the analysis were unmet load, over generation, annual purchase from grid, NPC (net present cost), as well as LCOE (levelized cost of energy) over 25 years lifespan of the system. The hybrid system had an NPC of ₦569.89 M, and an LCOE of ₦203/kWh in addition to reduction of unmet load to almost negligible as against grid only and PV-only. Average running cost per year was ₦29.17 million, representing significant cost savings and better supply-reliability. It is shown that PV-grid is both a technically and economically feasible approach to improving energy resilience in volatile and grid-deficient regions. This work provides one of the earliest institution-level techno-economic analyses of hybrid systems in northeast Nigeria and provides a generic model for other energy-poor regions across sub-Saharan Africa.

AREVA operates a world-wide unique thermal hydraulic platform to ensure high safety standards in the nuclear industries. This platform is operated as an accredited test and inspection body according to ISO 17025 and 17020 to grant a high and independently confirmed quality standard. The accreditation also ensures the independency of the organization and confidentiality to the individual stakeholders, for example research centers, utilities, components suppliers, engineering companies and vendors. Especially for nuclear power plants, it is very relevant to consider that reliability depends on the integrity of its components during its life time-from design through construction, operation and maintenance. For example, a typical NPP (nuclear power plant) has 1,000 to 2,000 large valves and 7,500 to 12,500 small valves, of which about 200 to 400 are designated Safety Class 1. The qualification of these Safety Class 1 components is relevant for reactor new builds but also for installed plants. This paper explains newly established qualification tasks, the corresponding testing infrastructure, and the state of the art of testing technology. By way of example, the paper describes the program and possible sequence of qualifying NPP safety-related components.

This paper features a comparative study performance of sliding mode controller (SMC) for closed-loop voltage control of direct current to direct current (DC-DC) three-cells buck converter connected in parallel, operating in continuous conduction mode (CCM), based on pulse-width modulation (PWM) with SMC based on hysteresis modulation (HM) where an adaptive feedforward technique is adopted. On one hand, for the PWM-based SM, the approach is to incorporate a fixed-frequency PWM scheme which is effectively a variant of SM control. On the other hand, for the HM-based SM, oncoming an adaptive feedforward control that makes the hysteresis band variable in the hysteresis modulator of the SM controller in the aim to restrict the switching frequency variation in the case of any change of the line input voltage or output load variation are introduced. The results obtained under load change, input change and reference change clearly demonstrates a similar dynamic response of both proposed tech...

Ensuring the stability of power systems during sudden disturbances remains a vital challenge, especially in large interconnected grids where electromechanical oscillations can threaten synchronized operation. This study explores the dynamic behavior of a synchronous turbo generator under such transient conditions, using advanced simulation techniques to assess the impact of three widely used FACTS controllers: the Static Var Compensator (SVC), Thyristor-Controlled Series Capacitor (TCSC), and Static Synchronous Compensator (STATCOM). A detailed nonlinear simulation framework was built in MATLAB to capture the generator's swing dynamics and evaluate its response under load disturbance. The system's performance was analyzed across essential parameters related to stability and damping. Among the three controllers, STATCOM emerged as the most effective. STATCOM was able to limit the initial deviation of the rotor angle more effectively, which is a critical factor in preventing loss of synchronism during disturbances. The TCSC also showed promising performance in damping ratio and settling time, while the SVC lagged behind with slower damping characteristics by damping ratio and longer settling time. Rotor angle stability margin was maximized with STATCOM, reducing the risk of cascading instability in multi-machine systems. These findings highlight the effectiveness of FACTS devices particularly STATCOM in enhancing the dynamic stability of generators during transient events. The study offers practical insights for power system operators and grid planners looking to strengthen grid resilience through advanced damping strategies, especially in the context of evolving smart grid infrastructures.

Unified Power Flow Controller (UPFC) is a versatile FACTS device which can provide full dynamic control of a transmission line parameters, bus voltage, line impedance and phase angle for improved system security. However, the extent that performance of UPFC can be brought out, it greatly dependent upon the location and size of this device in the system. This paper present Differential Evolution (DE) Technique for optimal placement of UPFC device under steady state (i.e normal, moderate and critical) conditions and is aimed at real power loss minimization and voltage profile enhancement of an interconnected power system. The proposed method is applied on the IEEE 14 bus power system which is demonstrated through MATPOWER simulation package. The results obtained indicate that DE is robust and can significantly enhance the security of power system by reducing line losses and improved bus voltage profile within the acceptable limit.

A reversible fuel cell, also known as a "Unified Regenerative Fuel Cell," is an electrochemical component that can operate via conception in fuel and electrolyzer modes. Reversible fuel cells are based on proton exchange membrane fuel cells and solid oxide fuel cell technologies, which have been proposed to address energy storage and conversion challenges, providing versatile pathways for renewable fuel production. However, both technologies suffer challenges associated with cost, durability, low round-trip efficiency, and the need to separate H2O from the product fuel. Reversible fuel cells present an innovative opportunity for New York State to transition towards a cleaner and more sustainable energy future. These versatile devices can efficiently convert electricity into hydrogen and oxygen through electrolysis and reverse the chemical reaction to generate power when needed. By harnessing renewable energy sources, such as solar and wind, New York can produce and store hydrogen during periods of peak production for later use. This helps balance the power grid, especially during high demand, and reduces reliance on fossil fuels. Reversible fuel cells can support the state's ambitious goals for reducing greenhouse gas emissions and increasing the use of renewable energy. Moreover, such technology could stimulate local economies by creating jobs in the renewable energy sector, contributing to economic growth. Additionally, New York's existing infrastructure, such as its extensive network of natural gas pipelines, could be adapted to distribute hydrogen, making it a practical choice for widespread adoption. New York can lead the way in clean technology innovation by investing in research, development, and pilot projects for reversible fuel cells, thereby ensuring energy security and environmental sustainability for future generations.

The paper is concerned with the Power System Protection schemes and the resulting design requirement that enhances stability as well as control with the implementation of TCP/IP. It discusses the architecture that upgrades the existing scheme by controlling all the control signals traffic between generating units, transmission system, connected loads and protection devices that are sensitive to control signals using TCP/IP and results are compared using Graphics User Interface (GUI) in MATLAB/Simulink. Protection system describes latest breakers circuit using indirect tripping command from generating units that protects load side through load breakers that receives action signal from local controllers that have a direct communication linkage with main server having strong data base, directly monitors everything through TCP/IP platform using GUI.

The paper is based on the experimental investigation of accelerated stresses on insulation of power transformer. The effects of individual thermal and electrical stresses have been graphically presented. The factors accelerated thermal aging factor (ATAF) and accelerated electrical aging factor (AEAF) have been introduced, it helps to understand the contribution of thermal and electrical stresses and degradation trends of insulating properties. The accelerated aging factors have been mathematically correlated with different properties of insulation such as moisture, breakdown voltage (BDV), tan delta and resistivity. These parameters were determined experimentally for fresh oil samples and for samples subjected to accelerated aging.

This paper deals with the human adaptability to its built environment. The built environment as we know it rarely finds itself adapting to its surrounding context, whether it be on the level of interaction with humans or the climate. Humans and nature both are in a constant state of flux; moving, changing, sensing, and reacting to their context and information they gather and perceive. A barrier is formed between the built environment and humans and nature due to the fact that their inherent characteristics are utterly contrasting. It is commonly estimated that persons in urban areas spend at least 80% of their time indoors. This suggests that the quality of the indoor environment can have a significant impact on comfort, health, and overall sense of well being. The indoor environment of buildings should thus be designed and controlled, as to provide a comfortable and healthy space for occupants. In order to maintain the quality of the indoor environment, we mechanically condition our buildings to achieve constant, uniform and comfortable environments. The maintenance of thermal equilibrium between the human body and its environment is one of the primary requirements. History of thermal comfort and climate design shows a definite relation between them and research is needed to know "What are comfort conditions?" and "How buildings could adapt themselves to these conditions".

Micro-grid plays a vital role in fulfilling the increasing demand by using distributed renewable energy resources. Demand and response technique can be broadly classified under the setup DR deployed (e.g. ISO's/RTO's). Demand response program can be implemented to improve power system quality, reliability and increasing demand. In modern power industry, strategic player can take more benefit from more emphasized DR study in terms of social benefit (uninterrupted power supply to consumers) and economy. This paper proposes the distributed micro-grid control and implemented control setup implemented demand response algorithm, which provides better power system reliability. This paper presents contingencies control demand and response for micro-grid. The main advantage of implementation of demand and response algorithms in Micro-grids provides reliable power supplies to consumers. The proposed micro-grid TCP/IP setup provides a chance to respond the contingencies to recover the shed to active condition. Micro-grid controller implements demand and response algorithm reasonable for managing the demand of the load and intelligent load scheme in case of blackout.

Based on wind-speed records of Alaska's 19 first-order weather stations, we analyzed the near-surface wind-speed stilling for January 1, 1984 to December 31, 2016. With exception of Big Delta that indicates an increase of 0.0157 m•s-1 •a-1 , on average, all other first-order weather stations show declining trends in the near-surface wind speeds. In most cases, the average trends are less then-0.0300 m•s-1 •a-1. The strongest average trend of-0.0500 m•s-1 •a-1 occurred at Homer, followed by-0.0492 m•s-1 •a-1 at Bettles, and-0.0453 m•s-1 •a-1 at Yakutat, while the declining trend at Barrow is marginal. The impact of the near-surface wind-speed stilling on the wind-power potential expressed by the wind-power density was predicted and compared with the wind-power classification of the National Renewable Energy Laboratory and the Alaska Energy Authority. This wind-power potential is, however, of subordinate importance because wind turbines only extract a fraction of the kinetic energy from the wind field characterized by the power efficiency. Since wind turbine technology has notably improved during the past 35 years, we hypothetically used seven currently available wind turbines of different rated power and three different shear exponents to assess the wind-power sustainability under changing wind regimes. The shear exponents 1/10, 1/7, and 1/5 served to examine the range of wind power for various conditions of thermal stratification.

Analysing the two-phase flow behaviour of cryogenic propellants like LH 2-VH 2 and the accompanying flow regime utilizing volume fraction is made easier by the current analysis. Additionally, two phases of liquid hydrogen (LH 2) in different inlet velocities and temperatures have been described in the current work. With the aid of the commercial CFD program Ansys Fluent, a two-dimensional computer model of a cryogenic feed line, has been created for the present study. To characterize the two-phase flow of LH 2 and to accurately estimate hydrodynamic and thermodynamic properties under various situations, the volume of fluid (VOF) approach based on an Eulerian flow scheme incorporated with an energy equation is used. These models have been validated with experimental data, and the trend of volume fraction captured matches the computational result. The flow visualization and the volume fraction has evaluated along with bulk mean temperature (Tb) and velocity analysis. Therefore, the current methodology may be used to estimate the flow shape and phase distribution at different initial conditions.

The liberalization of the energy market has led to a surge in unforeseen power exchanges, which could jeopardize the security of the power system by overloading transmission lines. Flexible AC transmission system devices (FACTSDEV) has been developed in order to improve voltage profiles, reduce losses, and solve power system instability. However, because FACTSDEV devices have such high initial costs, careful planning and ideal placement are essential to maximizing their benefits. This paper proposes a genetic algorithm-based approach to arrange multiple FACTSDEV devices in a power system optimally under N-1 contingency conditions. The IEEE standard (IEEESTD) 14 bus network is where FACTSEDV are located using this optimization technique. The study makes use of MATLAB simulations to evaluate how different FACTSDEV and their placements affect the performance of the power system. The results of the generator and line outage simulations show how FACTDEV have an impact on generation costs, system loss components, and line loss reduction. The cost-optimized placement findings for FACTSDEVs in the IEEESTD 14 bus system are satisfactory and show an improvement in generation cost and system loss component with appropriate positioning and sizing of FACTDEVs.

This paper considers the use of the inherent structural characteristics of power system networks for improving the reactive power reserve margins for both topologically weak and strong networks. The inherent structural characteristics of the network are derived from the Schur complement of the partitioned Y-admittance matrix using circuit theory representations. Results show that topologically strong networks, operating close to the upper voltage limit could be made to increase their loadability margin by locating reactive power compensators close to generator sources, whereas topologically weak (ill conditioned) networks could be made to operate within the feasible operating limits by locating reactive power compensators on buses farther from generator sources.

Hybrid photovoltaic-diesel systems are becoming more and more attractive for rural electrification in sub-Saharan Africa region. In this paper, some energy management strategies for a photovoltaic-diesel system without battery storage have been theoretically and experimentally studied. The proposed strategies are respectively based on active power control of inverters and controllable loads to ensure security operation for the system and maximize the solar energy penetration. Simulations and experiments have been performed under two different climate conditions and have been applied to an African rural load profile. All the energy management strategies developed have been implemented with the Matlab environment. The obtained results have shown the effectiveness of the proposed strategies to avoid power reserve to the diesel generator, to increase solar energy fraction, to reduce CO 2 emissions, and to ensure the system's frequency and voltage stability.

This study explores the implementation of path-planning algorithms in resource-constrained autonomous vehicles within a university environment, specifically NSBM Green University. Unlike most studies that assume abundant resources, this research focuses on cost-effective solutions suitable for environments with limited financial and computational capabilities. The methodology involved an extensive review and analysis of existing pathplanning algorithms and localization methods, followed by simulations using MATLAB. The selected algorithm, Hybrid A*, was optimized to balance computational efficiency, path accuracy, path length, and obstacle avoidance. The results confirmed that reliable autonomous navigation is achievable even under resource constraints. Future work will involve creating a more detailed map of the university and testing more complex algorithms to further enhance the robustness of the path planning system. Additionally, the optimized algorithm could be tested in real-world scenarios to validate its practical feasibility for autonomous navigation.

Briquette technology is an alternative green energy source to offset the increasing demand for charcoal and firewood to save the forests and the environment while creating employment for youth and women. Using the scoping and realistic review techniques, a review study was conducted to establish the briquette technology's existence, and its value chain, identify stakeholders and challenges along the value chain and explore the policies supporting the technology and potential employment opportunities for youth in the green energy sector. The review results indicated that the briquette technology value chain consists of sourcing raw materials, production process, distribution, and consumption as its components while transportation, storage or packaging, marketing, and training are its supporting services. In addition, it was found that stakeholders in the value chain are manufacturers, producers, and supporting service providers who differ based on their formalities, such as groups, companies, government organizations, Non-Governmental Organizations (NGOs), institutions, and enterprises. Furthermore, five challenges were identified that impair the briquette adoption. They include the technology, raw materials, and the quality of briquettes, promotion, and marketing. Also, the study found that there are limited policies that provide a conducive environment for briquette technology to flourish. The study concludes that briquette technology exists in Tanzania. However, it is not yet matured as compared to the developed countries, and the technology is not backstopped by existing policies. The study recommends the briquette technology as a viable employment opportunity, especially for youth and women; therefore, the formulated briquette value chain should be utilized for easy coordination of stakeholders and deployment of the technology. Also, there is a need to create

To increase the power output of a PV module or a field of PV modules, an electronic controller is incorporated between the PV generator and the load, whose role and main objective is the continuous monitoring of the maximum power point of the PV generator commonly known as MPPT (Maximum Power Point Tracking) and this in general per action on a DC-DC conversion device. The regulation and control techniques provide the impedance matching function, transferring to the load the maximum electrical power output from the PV generator in any the temperature and sunshine conditions. The development of a revolutionary method based on neural algorithms for the prediction of an instantaneous command is the main objective in our work. Indeed, the paper presents a new control strategy for the photovoltaic PV, it is a command based on Neuronal Network technique. It is the first time that this technique has been introduced, and proposed by the authors in synthesizing control laws for the converters of electronic power. The new technical algorithm based on Neural Networks, is designed to be more robust in performance with respect to tracking speed and precision. Moreover, this new successful technical research, provides a robust neural structure compared to the noisy empirical data used for the prediction of the command. Consequently a smooth control signal without oscillation, targeting exactly the expected optimal control with an independent control of the sampling frequency of the system. This study, which is followed by a simulation, has enabled us to consolidate the idea that the new Neural Network controller when compared to their classical counterparts, and obtains the best performances concerning the speed of tracking and precision. The robustness of the networks of neurons opposite the noise of measurements, like, the smoothness of the power signal of PV system generated during the application of the neuronal order, will qualify this command as a practical alternative to the disadvantages recorded on the levels of the classical methods.

Matching an embedded electronic application with a<br> cantilever vibration energy harvester remains a difficult endeavour<br> due to the large number of factors influencing the output power.<br> In the presented work, complementary balanced energy harvester<br> parametrization is used as a methodology for simplification of<br> harvester integration in electronic applications. This is achieved<br> by a dual approach consisting of an adaptation of the general<br> parametrization methodology in conjunction with a straight forward<br> harvester benchmarking strategy. For this purpose, the design and<br> implementation of a suitable user friendly cantilever energy harvester<br> benchmarking platform is discussed. Its effectiveness is demonstrated<br> by applying the methodology to a commercially available Mide<br> V21BL vibration energy harvester, with excitation amplitude and<br> frequency as variables.

The paper is concerned with the Power System Protection schemes and the resulting design requirement that enhances stability as well as control with the implementation of TCP/IP. It discusses the architecture that upgrades the existing scheme by controlling all the control signals traffic between generating units, transmission system, connected loads and protection devices that are sensitive to control signals using TCP/IP and results are compared using Graphics User Interface (GUI) in MATLAB/Simulink. Protection system describes latest breakers circuit using indirect tripping command from generating units that protects load side through load breakers that receives action signal from local controllers that have a direct communication linkage with main server having strong data base, directly monitors everything through TCP/IP platform using GUI.

Using circuit diagrams presented in literature, two types of Constant Current (CC) charge controllers were built for experimental purposes and used to charge and discharge batteries at different time intervals, at different current rates and their corresponding efficiency values were computed and compared. In separate experiments, batteries were used to store battery capacity at different charge and discharge rates, from which it was confirmed that with 10Ah capacity stored separately in the old Vanbo and the Vanbo at different current rates, the charging efficiency for the older battery was lower than that of the newer battery. The end voltages after charge varied in a non-proportionate manner with the constant charging current rates tested for old batteries. For the new battery, the efficiencies obtained were higher than those of the old battery. It shows then that charge and discharge cycles at different magnitudes of CC can be used to determine the state of health of lead-acid batteries. It was also found that an increase in their aging process doesn't only lower charge/discharge efficiency, it disrupts end voltage variations after charge, without considerable change in connection with the magnitude of battery capacity tested.

Climate change phenomenal is a trend that impacts the local communities by affecting their way of life. High demand for wood products to meet the demand of energy supply in Maasai-Mau region has seen the depletion of the forest cover thus increasing carbon dioxide emission and other greenhouse gases into the atmosphere. However, there is no extensive research on the benefits of alternative sources of energy like solar, biogas and biomass briquette in mitigating these impacts. The study investigated the adoption of biomass briquettes as an alternative source of energy in Maasai-Mau, Narok County, Kenya. The study was guided with three objectives (i) to determine the level of adoption of biomass briquette in Maasai-Mau region, (ii) to evaluate the challenges and hindrances Maasai-Mau residents face in the adoption of biomass briquettes in Maasai-Mau region and (iii) to investigate the availability of biomass briquette making materials in Maasai-Mau region. The study used two sampling techniques; systematic and purposive sampling to get information from the key informants and households in the study area with a target sample of 100 respondents. The findings obtained were analysed through Excel and Statistical Package of Social Sciences. Data results were presented in graphs, pie-charts, and tables. From the results, the hypothesis was analysed by Chi-square (2). The study failed to reject the null hypothesis of a relatively low level of education hinders the adoption of biomass briquette, where (2 =9.866, DF=6, P=0.13). The study concluded that the level of biomass adoption in Maasai-Mau region was relatively low with only 28% of the households using briquettes daily as compared to other sources of energy. The other conclusion from the study was that biomass briquette making materials were readily available with saw dust chippings and charcoal dusts ranking 84.61% and 79.49% respectively. Finally, the study found out that lack of funds and lack of briquette making skills were the highest challenge to adoption of briquette making technology in the region, being ranked as 88% and 77.6% respectively. The primary recommendations were that the Massai-Mau region residents be educated on biomass briquette making skills, and ensuring that their biomass briquette initiatives are funded to solve the challenges they face while adopting this clean energy mechanism as an alternative source of energy.

The paper is concerned with the Power System Protection schemes and the resulting design requirement that enhances stability as well as control with the implementation of TCP/IP. It discusses the architecture that upgrades the existing scheme by controlling all the control signals traffic between generating units, transmission system, connected loads and protection devices that are sensitive to control signals using TCP/IP and results are compared using Graphics User Interface (GUI) in MATLAB/Simulink. Protection system describes latest breakers circuit using indirect tripping command from generating units that protects load side through load breakers that receives action signal from local controllers that have a direct communication linkage with main server having strong data base, directly monitors everything through TCP/IP platform using GUI.

This work presents a study on the influence of the main operating variables on the gas turbine cycle. A numerical simulation of a gas turbine cycle is performed for a real net power of 100 MW. A calculation code is developed using EES software. The operating variables are taken in conformity with the local environmental conditions adopted by the Tunisian Society of Electricity and Gas. Results show that the increase of ambient temperature leads to an increase of Tpz and NO<sub>x</sub> emissions rate and a decrease of cycle efficiency and UHC emissions. The CO emissions decrease with the raise of residence time, while NO<sub>x</sub> emissions rate increases and UHC emissions rate decreases. Furthermore, both of cycle efficiency and NOx emissions increase with the increase of the pressure ratio.

This paper presents a numerical characterization of copper-indium-gallium-diselenide thin film solar cells using one dimensional simulation program (SCAPS-1D). We have performed an optimization of the performances of the standard Mo/Cu(In,Ga)Se 2 /CdS/ZnO solar cells using current-voltage and quantum efficiency methods. With a CuIn 0.7 Ga 0.3 Se 2 absorber, we have investigated the buffer layer thickness, temperature, series and shunt resistances effects on the open-circuit voltage, short-circuit current density, fill factor, conversion efficiency and quantum efficiency. The simulated results show good performances when the thickness of the buffer layer is in the range of 10-40 nm due to the reduction of absorption in the short wavelenghts (380-500 nm). High performances of the model is obtained when the series and shunt resistances is in the range of 0.1-1 Ω•cm² and 1,000 Ω•cm², respectively. Under these conditions, the cell can theoretically operate under an ambiant temperature of 370 K without any loss of its performances.

An attempt is made to design, fabricate and analyze a cylindrical trough solar collector system. An Evacuated Aluminium receiver has been used in the focal plane of the system to receive the thermal energy and water has been used as the heat transfer fluid to collect the thermal energy from the present system. Different heat transfer mechanisms, i.e., the heat transfer mechanism through convection of the internal receiver, in the circular among the linear receiver tube and cover glass, from the cover glass tube to the ambience air, the heat transfer mechanism through glass cover to the linear receiver tube to cover glass walls, Radiative heat transfer mechanism through Radiation from the linear receiver tube to glass cover walls and glass cover surfaces to ambience have been evaluated and interpreted. Thermal modelling for the proposed system is done and the results are correlated with the empirical observations intended for validation of the model.

The preventative strategies for N -1 network security dominant in European networks mean that network capacity is kept free in case a line fails. If instead fast corrective actions are used to overcome network overloading when single lines fail, this has the potential to free up network capacity that is otherwise underused in preventive N -1 security strategies. In this paper, we investigate the impact on renewable integration of a corrective network security strategy, whereby storage or other flexibility assets are used to correct overloading shortly after line outages. In this way, we find significant cost savings for the integration of renewable energy of up to 2.4 billion euros per year in a aggregated 50-bus model of the German power system utilizing these flexibility assets, so-called network boosters (NB). This offers a role for storage beyond energy arbitrage or ancillary services like frequency control. While previous literature has focused on the potential savings of NB in the short-term operation, we focus on the long-term benefits in systems with high shares of renewable energy sources, where the capacities and dispatch of generation and NB are optimised. We demonstrate the benefits of NB for various shares of renewable energy, NB and flexibility costs, as well as different allowed levels of temporary overloading the lines in both (i) a sequential model, where long-run generation investments are optimised separately from the NB capacities, and (ii) a simultaneous model, where generation is co-optimised with NB investment so that mixed preventive-corrective approaches are possible.

High standards of living are linked with the availability of energy. Therefore, there is always a requirement to modify existing power generating systems or to add new systems to fulfill the increasing demands of energy. It is becoming a core issue in the South Asian region so that at least current standards of living could be maintained by controlling growing energy rates and shortening the availability of conventional sources. Furnace oil is a residue obtained in the process of distillation of crude oil in the petroleum industry. This furnace oil is applicable for power generation plants allied with the petroleum industry so that residue of oil refineries could be utilized. In this research, a furnace oil-based power plant is designed in electrical transient and analysis program (ETAP) software. Moreover, steady-state and transient analysis of the proposed design of the power plant are conducted to increase practical viability of model. Load flow is analyzed to depict the performance of the power plant model under load conditions. This model is further tested under the motor starting event to analyze the current drawn by the motor. This event helps to determine the permissible values of protective equipment installed in power plants. In the last, economic dispatch analysis is conducted to find the relative minima of generation cost of furnace oil-based power plant with respect to coal and hydel generation

There are several sources of energy recovery in the ambient environment. The radiofrequency energy harvesting system is used to harvest the electromagnetic energy in the air by processing energy sources to charge low-power electronic devices. Rectenna termed as a rectifying antenna is a device that is used to convert electromagnetic waves in the air into direct electric current. In this work, we have designed firstly the patch antenna with a small size printed on the FR4 substrate (40 mm × 47.5 mm × 1.6 mm) and then the rectifier circuit. This rectenna is capable of working at a frequency range of 2.45 GHz. The antenna was designed using High Frequency Structure Simulator (HFSS) 13.0 software with the result of working frequency of 2.453 GHz, S11 (Return Loss) −52 dB, Voltage Standing Wave Ratio (VSWR) 1.036, gain 3.48 dB and bandwidth 150 MHz. The efficiency of rectifier design on Advanced Design System (ADS) 2011 software is 54% at the input power of 0 dBm at 2.45 GHz. The resulting system is capable of producing electrical energy to power low-power electronic equipment at a DC voltage of 732 mV.

Obviously, the outside annual climate change caused either by a major solar input during the hottest period or by a temperature drop during the coldest period leads to discomfort inside buildings. This effect can be reduced by storing heat transmitted in phase change materials (PCM) as latent heat, in order to ensure a good situation of thermal comfort during all months of the year. In this work, thermal behavior of two roofing systems is studied. One roof is constituted only by usual materials in building. In the other, two phase change materials (PCM) are introduced according to three configurations. Study is interested to assess incorporation effect of two PCMs within the roof and to evaluate the optimum locations to reduce the energy consumption of air-conditioned room. Mono-dimensional numerical model validated analytically and experimentally, is used to carry out a parametric analyzes to determine characteristics of the layers in which the roofs are formed regardless of external climate effect. Numerical calculations are performed for three configurations of roof. Results show that insertion of phase change materials in roof provides best energy consumption saving regardless annual climate change. Generally, the three configurations lead to different results, depending on the combination of PCMs. This difference becomes less important when selection of PCMs takes account the thermal comfort level and temperatures of hottest and coldest periods.

The present study focuses on the design and choice of materials (steels S355 and 45SCD6) of a chassis of stirred tank (with a variable filling rate) for use in the manufacturing of cosmetic products. This tank or trough will be submitted to important mechanical and thermal loads and pressure according to the various manufacturing processes. The authors propose a model of thermal and mechanical loads which takes into account the operating conditions of the tank. The analysis of the first 10 modes of vibration of the frame shows that the frequencies are much higher when the filling rate is high. They are higher for steel 45SCD6 than for the S355. The simulation results show that for a selected type of steel, the equivalent Von Mises stress increases along with increase in fill rates and thermal gradient. It appears that the influence of the thermal gradient is predominant. For both steels, the Von Mises equivalent stress is maximum in the beam 32 when the thermal gradient is at its lowest stage, and in the beam 40 for the greatest thermal gradient.

This paper focuses on hybrid electricity generation systems as an alternative to solo dependency on diesel generators for remote location such as Rigolet island, Labrador. The potential of extracting PV (photovoltaic) and wind energy to generate electrical power along diesel generators is scrutinized in this study. This paper provides effective modeling, sizing, and system architecture to reduce carbon footprint and operational costs. To make the most economical and reliable system design, this paper employs the optimization feature of the HOMER Pro. This software is used for the steady state analysis of the systems. In addition, MATLAB Simulink is used to represent the hybrid system for dynamic simulations and cloud data logging system for SCADA control. The stability and power output of the system are analyzed under varying load conditions. Overall, this paper covers simulation results and comprehensive system details.

New approaches must be taken due to the rapid growth of societies globally and the urgent need for more energy, climate change, and global warming. One of these approaches is supporting and expanding new and efficient renewable energy resources (RERs). Therefore, this paper is dedicated to the energy planning and management of the proposed structure in which novel renewable-based technologies such as INVELOX wind turbines, Bi-facial photovoltaic (PV) panels, and tidal turbines (TT), in addition to the demand response programs (DRP) especially time of use (TOU), are investigated. The purpose is to simultaneously reducing the presented system's overall cost and environmental pollution. The problem is modeled as mixed-integer linear programming (MILP) in GAMS software and solved using a CPLEX solver. The final results show that novel technologies recognized as efficient can significantly reduce contamination, expenses, and greenhouse gas (GHG) emissions while supplying our rapidly growing demand.

In this work, we present an experimental transient 3-Dimensionnal study for the minority charge carriers' effective lifetime measurement under magnetic field in transient dynamic state. The magnitude of the magnetic field B is varied from 0 mT to 0.03 mT. The method used is mainly based on the open circuit voltage decay method. The solar cell is injected by a low electrical excitation which protects against capacitance effects. Our approach is based on the open circuit voltage decay response analysis. From an experimental setup , we get the transient voltage data on a digital scope. The data are used for plotting transient voltage decay curves. The curves obtained and analyzed are fitted in their linear zone. This zone presents an ideal decay which permits to get good values of lifetime. The slope of the linear decay is inversely proportional to effective lifetime. The results of fitting permit determinate the effective charge carriers' lifetime directly. The results obtained are then presented and analyzed. The observations indicate that the charge carriers effective lifetime decrease when the magnetic field increases.

Recently, regression artificial neural networks are used to model various systems that have high dimensionality with nonlinear relations. The system under study must have enough dataset available to train the neural network. The aim of this work is to apply and experiment various options effects on feed-foreword artificial neural network (ANN) which used to obtain regression model that predicts electrical output power (EP) of combined cycle power plant based on 4 inputs. Dataset is obtained from an open online source. The work shows and explains the stochastic behavior of the regression neural, experiments the effect of number of neurons of the hidden layers. It shows also higher performance for larger training dataset size; at the other hand, it shows different effect of larger number of variables as input. In addition, two different training functions are applied and compared. Lastly, simple statistical study on the error between real values and estimated values using ANN is conducted, which shows the reliability of the model. This paper provides a quick reference to the effects of main parameters of regression neural networks.

This investigation contributes to a better understanding of condensation heat transfer in horizontal non-circular microchannels. For this purpose, the conservation equations of mass, momentum and energy have been numerically solved in both phases (liquid and vapor), and all the more so the film thickness analytical expression has been established. Numerical results relative to variations of the meniscus curvature radius, the condensate film thickness, the condensation length and heat transfer coefficients, are analyzed in terms of the influencing physical and geometrical quantities. The effect of the microchannel shapes on the average Nusselt number is highlighted by studying condensation of steam insquare, rectangular and equilateral triangular microchannels with the same hydraulic diameter of 250 µm.

Power system stability is a very important issue in power system engineering because a decrease in the stability margins can cause unacceptable operating conditions, which leads to frequent failures. In this paper, SKM POWER TOOLS PTW-32 Version 4.5.2.0 was used to study different Stability recovery tests after a medium voltage short circuit fault on a turbine generator in the power system. The analysis focused on the generator electrical and mechanical powers stability recovery test, generator speed stability recovery test, excitation voltage stability recovery test, bus voltage and bus frequency stability recovery test. In our study, when the introduced fault was cleared after 0.5 s, it reveals that the recovery rate of electrical power was much faster than that of mechanical power. Also, the results reveal that it took about 10 seconds for the turbine speed to stabilize while it took fewer seconds for the frequency to stabilize.

The ability of power system to survive the transition from preloading state to the gradual increase in load and thereafter reach an acceptable operational condition is an indication of transient stability of the system. The study analyzed load shedding scheme through the use of empirical measurement tools and load-flow simulation techniques. It was geared towards determining effective load shedding strategies to reduce unnecessary overload in order to achieve dynamic stability of the electric power network in the Export Free Trade Zone, Calabar, Nigeria. From the tests and the measurements taken, it was observed that the real and reactive powers from the generator and the mechanical power from the turbine engine were stable when the load shedding controller was switched on, as compared to when it was off. The engine speed, the bus-bar frequency and the output voltage of the generator stabilized within a shorter time (about 8 seconds) when the controller was switched on than when it was on the off condition. Also, there were noticeable fluctuations in the speed of the remaining two generators. It became stable at about 12 seconds after the loss. The variations were 0.3 per cent of the nominal speed value. The excitation voltage fluctuated from 1.2 (pu) to 4.5 (pu) when the bus voltage dipped as a result of additional load. It then came down and stabilized at 1.8 (pu) after few swings. This confirmed that the stability of power system is much enhanced when load shedding controllers are effectively configured on the network.

The paper is concerned with the Power System Protection schemes and the resulting design requirement that enhances stability as well as control with the implementation of TCP/IP. It discusses the architecture that upgrades the existing scheme by controlling all the control signals traffic between generating units, transmission system, connected loads and protection devices that are sensitive to control signals using TCP/IP and results are compared using Graphics User Interface (GUI) in MATLAB/Simulink. Protection system describes latest breakers circuit using indirect tripping command from generating units that protects load side through load breakers that receives action signal from local controllers that have a direct communication linkage with main server having strong data base, directly monitors everything through TCP/IP platform using GUI.

The availability of non-renewable energy sources such as crude oil, natural gas, coal etc., is fast diminishing. So the renewable energy sources such as solar, hydropower, geothermal, wind, tidal energy, are gaining more and more importance. Many new developments to convert these renewable energy sources into usable forms are taking place. Most renewable energy sources are used to produce electricity. In this paper, a performance and efficiency simulation study of a smart-grid connected photovoltaic system using Chroma DC programmable power supply, AC programmable source and an Aurora Inverter is proposed. The simulation is performed in MATLAB environment where the Current-Voltage (I-V) and Power-Voltage (P-V) curves from the solar array simulator are generated and plotted. The proposed topology has been verified with satisfactory results. In addition, temperature and irradiance effects on I-V and P-V characteristic curves are verified. Also, the efficiency curves of the photovoltaic grid interface inverter are generated in the study. The MATLAB code developed in this paper is a valuable tool for design engineers comparing different inverters, calculating the optimum efficiency of a given inverter type.

Load flow is an important tool used by power engineers for planning, to determine the best operation for a power system and exchange of power between utility companies. In order to have an efficient operating power system, it is necessary to determine which method is suitable and efficient for the system's load flow analysis. A power flow analysis method may take a long time and therefore prevent achieving an accurate result to a power flow solution because of continuous changes in power demand and generations. This paper presents analysis of the load flow problem in power system planning studies. The numerical methods: Gauss-Seidel, Newton-Raphson and Fast Decoupled methods were compared for a power flow analysis solution. Simulation is carried out using Matlab for test cases of IEEE 9-Bus, IEEE 30-Bus and IEEE 57-Bus system. The simulation results were compared for number of iteration, computational time, tolerance value and convergence. The compared results show that Newton-Raphson is the most reliable method because it has the least number of iteration and converges faster.

Recently, regression artificial neural networks are used to model various systems that have high dimensionality with nonlinear relations. The system under study must have enough dataset available to train the neural network. The aim of this work is to apply and experiment various options effects on feed-foreword artificial neural network (ANN) which used to obtain regression model that predicts electrical output power (EP) of combined cycle power plant based on 4 inputs. Dataset is obtained from an open online source. The work shows and explains the stochastic behavior of the regression neural, experiments the effect of number of neurons of the hidden layers. It shows also higher performance for larger training dataset size; at the other hand, it shows different effect of larger number of variables as input. In addition, two different training functions are applied and compared. Lastly, simple statistical study on the error between real values and estimated values using ANN is conducted, which shows the reliability of the model. This paper provides a quick reference to the effects of main parameters of regression neural networks.

This work is dedicated to the improvement of effusion cooling efficiency on combustion liners, by using an innovative multiperforation made of shaped holes of elliptical crosssection. Low-temperature experiments provided a spatial characterization of cooling efficiency in a suction-type wind tunnel, whereas discrete measurements were performed in the engine-like conditions of THALIE facility. A RANS computational study was also performed to give a detailed insight on the aerothermodynamics of the complex flow created by effusion holes. Experimental and numerical data confirm the enhancement of effusion cooling by shaped holes, thanks to a better coverage of the first rows of the plate, and a better individual efficiency of each hole.

Simulated results from a detailed elementary reaction mechanism for methane-containing species in flames consisting of nitrogen (NO x), C 1 or C 2 fuels are presented, and compared with reduced mechanism; this mechanism have been constructed with the analysis of the rate sensitivity matrix f (PCAF method), and the computational singular perturbation (CSP). The analysis was performed on solutions of unstrained adiabatic premixed flames with detailed chemical kinetics described by GRI 3.0 for methane including NO x formation. A 9-step reduced mechanism for methane has been constructed which reproduces accurately laminar burning velocities, flame temperatures and mass fraction distributions of major species for the whole flammability range. Many steady-state species are also predicted satisfactorily. This mechanism is especially for lean flames. This mechanism is accurate for a wide range of the equivalence ratio (1, 0.9, 0.8, and 0.7) and for pressures as high as 40 atm to 60 atm. For both fuels, the CSP algorithm automatically pointed to the same steady-state species as those identified by laborious analysis or intuition in the literature and the global reactions were similar to well established previous methane-reduced mechanisms. This implies that the method is very well suited for the study of complex mechanisms for heavy hydrocarbon combustion.

This paper propses a newly developed wake effect model to examine quantitative reliability for wind farm with turbines at different heights. Using wind shade and shear effect, power for each turbine is calculatted from the waked speed. To determine the operating states and transition times of all turbines, Monte Carlo is used for system simulation in the paper. Reliability indices of wind farm are calculated and compared in different cases.