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This paper proposes a generalisation of the regional extraction method used by Dietzenbacher at el. [(1993). The regional extraction method: EC input–output comparisons. Economic System Research, 5(2), 185–206. ]. The production system represented by an input–output table is broken down into three flow matrices: intermediate input, final demand, and value added. The approach of Dietzenbacher et al. (1993) focuses on the input matrix to obtain both the backward and forward dependencies. The present paper, offers an alternative approach includes the final demand matrix to calculate the backward dependencies, while the value-added matrix is included for the forward dependencies. These two approaches are then compared by applying them to the empirical data based on the EUREGIO database. The results indicate that the Dietzenbacher et al. approach underestimates the dependencies, and the difference between these two approaches could lead to a different ranking of the dependence of the regions. [ABSTRACT FROM AUTHOR]

CFD investigation of the behavior of a solar dryer for the dehydration of olive pomace Solar dehydration is a process that reduces the percentage of moisture in the product without using nonrenewable energy. The present research analyses the behavior of olive pomace in the drying process. This process is important due to the need to reduce its humidity since with low humidity, olive pomace has good energy potential and can be used as biomass. The drying curve is determined in which a reduction from 67.34 to 40.73% of humidity can be observed in 12 days of dehydration, and the lower heating value curve and the elemental analysis of the olive pomace sample collected in the olive mill are determined experimentally in the solar dehydrator and in a laboratory. The dehydrator is analyzed with the help of computational fluid dynamics in ANSYS Student software. In this study, attention was focused on observing the effects produced by variations in the height of the dehydration chamber, and it was determined that the optimal height of the dehydration chamber is 300 mm [ABSTRACT FROM AUTHOR]

Recently, renewable energy sources have become an encouraging solution to the availability and environmental problems arising from using fossil fuels for energy production. The article's goal is to provide a reliable and doable path toward producing electricity from biomass by using palm waste (fronds, empty fruit bunches, and trunks). The system is simulated using Cycle-Tempo software. Waste was gasified at 800°C using a downdraft fixed-bed reactor to produce syngas. After that, a producer gas flow of around is sent to an externally fired gas turbine (EFGT), where it is promptly burned at atmospheric pressure to produce electricity. According to the simulation's outcomes, palm fronds are the waste that worked best as a feedstock, and an estimated 390 kW of electric power could be generated by the externally fired gas turbine with a 19% electrical efficiency. The producer gas had a good molecular composition (H2 15.02%, CO 18.1%, CH4 1.25%, CO2 10.79%, H2O 8.17%, and N2 46.08%), a low heating value of up to (4.16 MJ/kg), a gasification efficiency of 77%, and a CHP efficiency of 61%. A comparison of the findings with previously published literature revealed that the proposed technology allows for the production of syngas with a satisfactory composition from palm fronds. [ABSTRACT FROM AUTHOR]

Backward/forward load flow algorithm is commonly used in the power system, particularly in radial distribution networks. However, the rapid development in the power electronics technologies makes power systems more flexible with the integration of Renewable Energy Resources (RESs) and compensation devices. Consequently, this paper presents simple models for wind turbine generators based on Squirrel Cage Induction Generator (SCIG) and Distribution Static Synchronous Compensator (DSTATCOM) into a backward/forward load flow algorithm. In the wind generator model, the mechanical powers are collected from the manufactures data where the electrical power is calculated through the SCIG equivalent circuit and injected as negative loads at the connected buses. The second model in this paper is the DSTATCOM devices which are utilized to recover the SCIG reactive power. In the proposed model, the connected DSTATCOM bus is converted to a voltage-controlled bus (PV-bus type) with zero active power. Moreover, the reactive power of the DSTATCOM is updated during the iterative process until the load flow convergence. The simplified models for both wind generators and DSTATCOM are validated based on standard IEEE 33-bus and 85-bus radial distribution systems. The obtained results show the feasibility and effectiveness of the proposed models. [ABSTRACT FROM AUTHOR]

This paper presents a modeling for D-STATCOM device into Monte Carlo probabilistic load flow algorithm. The model is used to improve the predictability and voltage profile of distribution networks. In this model, the D-STATCOM's bus is represented as a special generator bus which injects reactive power only. The injected reactive power of D-STATCOM is updated during the iterative process to maintain the voltage magnitude at the specified value. The model can be easily implemented in the original PLF code without deeply modifications. The probabilistic load flow (PLF) with D-STATCOM model is validated using various standard IEEE tests systems; 33-bus, and 69-bus systems. The PLF algorithm with DSTATCOM model has been evaluated based on MATLAB package. However, the obtained results prove the effectiveness of D-STATCOM implementation in the test systems regarding to predictability and voltage profile issues. Moreover, the standard deviation of the systems is decreased. [ABSTRACT FROM AUTHOR]

The article considers feasibility of using air-water heat pumps to provide residential and industrial buildings with heating, cooling and ventilation requires taking into account a large number of different factors, such as the estimated and average outdoor temperature for the heating period in the considered climate region. The study of temperature fluctuations during the heating period will help to clarify the boundaries of areas of synchronous changes to solve the problems of climatological zoning, with the goal of establishing the heat production, energy transformation coefficient of the selected heat pump model. Using a statistical data and quantitative indicators of temperature variability across the territory of Kazakhstan, an interactive online map was developed based on the ArcGIS software, which integrated 67 weather stations in five regions. The developed zoning map is a qualitatively new information product that combines reliable data and a tool for analysis, visualization and data management of a professional GIS system. In general, in conclusion, we can say that our work is the creation of a map of the zoning of the territory of Kazakhstan according to the average temperature of the heating period in order to select a heat pump heat supply system is relevant in that we take into account the climatic conditions and the heating season to select a heat transfer system. [ABSTRACT FROM AUTHOR]

In this article, the optimal allocation of compensation devices in power systems is determined using Improved Moth-flame Optimization (IMFO) algorithm. The main objective of this study is to maximize power system loadability, reduce total power system losses and enhance the voltage profile through finding the optimal locations and sizes of Static VAR Compensator (SVC) and Thyristor Controlled Compensator (TCSC). The methodology of this article is based on Continuation Power Flow (CPF) which is merged with IMFO in Optimum Power Flow (OPF) problem restricted by equality and inequality constraints. The proposed algorithm is implemented to regulate the required control variables. Both of single and multi-objective functions are applied on 57-IEEE bus test system to prove the performance of the proposed algorithm. The acquired simulation results by IMFO are compared with Moth Flame Optimization technique (MFO) and Multi Verse Optimizer (MVO) to emphasize the robustness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

This work is focused on the energy recovery potential of olive-oil industry wastes in the region of Tizi Ouzou (north of Algeria). A theoretical modelling and simulation study of a small-scale CHP plant fuelled with olive pomace and olive tree pruning is carried out. The power plant proposed is composed of a downdraft gasifier, an externally fired gas turbine reaching an optimum electric power of 75.8 and 170.22 kW of thermal power. The electric efficiency achieved is 18.56% and the CHP efficiency is 60.26% for olive tree pruning gasification. The simulation results showed a satisfactory syngas lower calorific value (4.12–4.39 MJ/kg) and a gasification efficiency of 78.3–79.8%. The economic analysis of the plant shows a feasible payback period between 5 and 6 years with an interesting Profitability Index and Internal Rate of Return above 20% for both biomasses considered. Finally, the electrical energy generated with the plant proposed can cover the annual consumption of more than 46,000 inhabitants in Tizi Ouzou province. [ABSTRACT FROM AUTHOR]

This paper proposes a novel hybrid (MFO-SCA) method based on Moth Flame Optimization (MFO) algorithm and Sine Cosine Algorithm (SCA). MFO is utilized for the exploitation phase while SCA is used for the exploration phase. In addition, the hybrid MFO-SCA method is used with combined power loss sensitivity (CPLS) to determine the optimal allocation of single and multiple of distributed generations (DGs) and capacitors in distribution system. In this paper, the total active power loss is used as a single objective function for incorporating DGs and capacitors in RDS. Also, this paper studies the system performance when integrating DGs or capacitors alone and DGs with capacitors simultaneously in RDS. The proposed method is validated using the standard IEEE 69-bus and IEEE 33-bus radial distribution system (RDS). From comparative study, the novel hybrid MFO-SCA proved its effectiveness in obtaining the best global optimum results of the objective function compared with other recent optimization techniques, especially SCA and MFO algorithms. [ABSTRACT FROM AUTHOR]

In this work, the immersion and invariance (I&I) control technique is used in order to design a new controller that stabilises the PVTOL (planar vertical take-off and landing) aircraft system. The controller gives priority to the control of the aircraft's altitude before controlling the lateral displacement, fact from which interesting features as less thrust effort and less aggressive manoeuvres for roll moment are gained. The fundamental idea for the development of the proposed controller is based on the selection of the target dynamic system in accordance with the nature of the translational motion system to then stabilise the off-manifold dynamics by using the rotational motion system. It is proved that the proposed control scheme is globally asymptotically stable. Simulation results validate our proposal. [ABSTRACT FROM AUTHOR]

The voltage stability analysis can be carried out using different continuation techniques. The continuation power flow that evaluates all power-flow solutions at different loading levels, is typically considered the most standard one. This approach is mainly based on two stages called predictor and corrector. The standard Newton–Raphson method is usually used at the corrector stage. In this paper, several corrector techniques based on efficient Newton-like methods are proposed in order to speed up the solution of continuation power flow. Consequently, two high order Newton-like methods as well as a fast corrector technique based on the Dishonest NR method have been proposed. A comprehensive study is addressed in order to check the suitability of the proposed corrector techniques compared with the standard Newton–Raphson (NR). Several small, medium, large and very large-scale test systems are used to achieve the validation. The obtained results prove the effectiveness and superiority of proposed techniques compared with the standard NR which conventionally used in corrector stage of the continuation power flow analysis in term of computational time. [ABSTRACT FROM AUTHOR]

This paper deals with the simultaneous tuning of proportional integral controller of static synchronous compensator (STATCOM) associated with lead-lag controller (LL) in order to improve the stability performance of combined wind farm (CWF). This type of farms has been developed to summarize the main benefits of Squirrel-Cage Induction Generator (SCIG) and doubly fed induction generators (DFIG). The performance of CWF with the tuned STATCOM is studied during line-to-line and three-phase faults. Multi-objective Lightning Attachment Procedure Optimization Algorithm (LAPO) is used as an intelligent optimization technique to determine the control parameters which can achieve the specified objective functions; minimizing the error signal and maximizing the output signal. The multi-objective LAPO is used to obtain the optimized values of AC voltage regulator, DC voltage regulator, current regulator, gains and time constant of LL. The ability of STATCOM tuned by multi-objective LAPO is examined by studying the performance of three wind farms. The first one is CWF and two other wind farms; one of them is based only on SCIG (SCIG-WF) and the other based only on DFIG (DFIG-WF) when they associated with the tuned STATCOM LAPO during grid fault. The results show that CWF associated with the tuned STATCOM LAPO has the best performance during grid faults compared with the other wind farms. [ABSTRACT FROM AUTHOR]

Recently, integration of distributed generations (DGs) and shunt capacitors in radial distribution network are becoming popular to withstand the rapidly increasing in electricity demands. In this article, a hybrid method is proposed to obtain the best locations and sizes of capacitors and DGs in radial distribution network. This hybrid method is based on chaotic whale optimization algorithm (CWOA) and loss sensitivity factor (LSF). The proposed method is tested on IEEE 69-bus system to enhance the buses voltages, increase the distribution system capacity, and decrease the total power loss. The obtained results prove that the proposed method based on CWOA and LSF can be highly effective in determining the locations and sizes of capacitors and DGs in RDS compared with other optimization techniques. [ABSTRACT FROM AUTHOR]

This paper presents a model to implement the switching technique of a novel isolated DC/DC converter of full-bridge to link fuel cell power output to the distribution system. The implementation was performed on a DSP F2812 of Texas Instruments. It is also proposed a new start-up system (software), to avoid overcurrent on the input side of inverter. This software avoids using an auxiliary circuit for start-up, so reducing costs, improving volume and weight and maintaining the same efficiency. A prototype has been implemented to validate the performance. Finally, comparative experimental results are presented. [ABSTRACT FROM AUTHOR]

In this article, a new hybrid metaheuristic optimization algorithm is proposed to solve the coordination problem of directional overcurrent relays (DOCRs). The proposed algorithm is constructed using hybrid whale optimization algorithm and gray wolf optimizer (HWGO) that enhance the performance and reliability of the traditional whale optimization algorithm (WOA). The proposed method enhances the exploitative phase of the WOA using a leadership hierarchy of the gray wolf optimizer (GWO) to find the best optimum solution. The coordination problem of DOCRs is subject to numerous constraints. The goal function for optimal coordination of DOCRs aims to minimize total operation time for all primary relay without violation in constraints to maintain reliability and security of the electric power system. The effectiveness of the proposed algorithm has been investigated on four different interconnected networks. The results using HWGO algorithm are compared with the original WOA, GWO, and earlier reported results of other optimization techniques. The results prove the viability of the proposed algorithm to solve the DOCR coordination problem and the ability of the proposed algorithm to overcomes the drawbacks and cover the weakness of the conventional WOA. [ABSTRACT FROM AUTHOR]

Although the wind farms based on squirrel cage induction generators (SCIG) is cheaper than the wind farms based on doubly fed induction generators (DFIG), it is always in desperate need for reactive power compensation. Nevertheless, the wind farms based on DFIG are expensive compared with the SCIG wind farm, it features by its ability to control the active power independent of reactive power. However, combined wind farm (CWF) has been developed to collect the benefits of SCIG and DFIG wind turbines in the same wind farm. In this article, artificial neural network (ANN) is used to evaluate gain parameters of static synchronous compensator (STATCOM) in order to improve the stability performance of CWF. The impact of tuned STATCOM on the performance of CWF during gust wind speed and during three-phase fault is comprehensively investigated. The performance of CWF with STATCOM tuned by ANN is compared with its performance when the STATCOM tuned by the multiobjective genetic algorithm (MOGA) and whale optimization algorithm (WOA). The results show that the performance of CWF can be enhanced using STATCOM tuned by ANN more than MOGA and WOA. [ABSTRACT FROM AUTHOR]

Generalized Unified Power Flow Controller (GUPFC) is one of the newest Flexible AC transmission system (FACTS) devices based on voltage source converters. This paper presents a developed model of GUPFC based on power injection approach. The series converters of GUPFC is represented by injected complex loads as function of the specified powers flow, while the shunt converter is represented as a synchronous condenser that provides the reactive power compensation to control the bus voltage magnitude. The main advantage of the developed model is that the original structure and symmetry of the admittance and Jacobian matrices can still be kept avoiding the changes of the original Jacobian matrix. Consequently, the complexities of the load flow are reduced. This model includes simple strategies for handling the operating constraints of GUPFC, including the injected series and shunt voltages magnitude, currents of the series and shunt converters, and the real powers exchanged in the converters. The strategies are based on decreasing one or more values of specified values or by modifying the specified values as a function of the required constraint limits. The developed model and proposed strategies for handling violation of GUPFC operating constraints are tested on IEEE test systems such as 57-bus and 118-bus systems. [ABSTRACT FROM AUTHOR]

Borges’ relationship with Latin, and in particular with the work of Virgil was almost lifelong, and helps to explain Borges’ poetics. This paper will trace and explore this relationship, from the very early works such asFervor de Buenos AiresandLuna de enfrente, to his late work, in particularLos conjurados. Two key elements are essential in this analysis: a number of verses from Virgil’s first Eclogue, and the city of Geneva, a place of origins and endings. [ABSTRACT FROM PUBLISHER]

This article presents a new isolated DC/DC bidirectional converter with soft switching, using a transformer with two voltage taps and two full bridges with insulated-gate bipolar transistors (IGBTs), one on each side of the transformer to be integrated in hybrid systems of renewable energy. A large voltage conversion ratio can be achieved using this converter, in buck and booster modes. Also medium and high DC power can be converted with a good efficiency. Analysis and switching techniques have been reported. To verify the principle of operation, a laboratory prototype of 10 kW has been performed. Experimental results are presented, operating in boost mode. The switching algorithm used has been modelled in MATLAB-Simulink to generate C code. This code has been implemented in a DSP F2812, which has been used to build the prototype. [ABSTRACT FROM AUTHOR]

Abstract—This article shows a method to optimize the reliability of an electric power system by the introduction of distributed generation. The reliability index of the system is determined as the failure probability of the system. A hybrid method that uses a binary shuffled frog-leaping algorithm and probabilistic load flow is proposed to search a large number of combinations for location and size of biomass power plants and photovoltaic units. The combination with the best performance minimizes the reliability index (probability of failure) of the system. [ABSTRACT FROM PUBLISHER]

In this article a new bidirectional output stage ultra-sparse matrix converter (BOSUMC) is presented. This converter is designed for connecting a hybrid electrical system to a distributed generation network. The proposed converter comprises an input stage and an output stage with six bidirectional switches in such a way that both the input and output stages are linked with a DC link, which can be coupled to an electrolyser and a fuel cell. The converter allows the current to flow in both ways in its output stage, and if there is an excess of energy in the network, it can be transformed into electric direct current and later into hydrogen for its exploitation. For verifying the control algorithm of the BOSUMC, a laboratory prototype has been prepared using among other elements a Spectrum Digital eZdsp™ TMS320F2812 card. [ABSTRACT FROM PUBLISHER]

There are several types of fuel cells being developed for a variety of applications. The solid-oxide fuel cell is in an entirely solid state with no liquid components. This paper discusses the potential of a solid-oxide fuel cell fed by natural gas to serve locally as voltage support for the ac bus. A grid-connected fuel-cell plant consists of the fuel cell and the voltage-source inverter. The flux-vector control is used very effectively for the control of this inverter. Simulation results are presented to evaluate the performance of this fuel cell plant to alleviate voltage problems present on the ac grid. [ABSTRACT FROM AUTHOR]

In this article, the concept of a new simple neuro-fuzzy control scheme for a combined-cycle power plant is presented. Gasification technologies under development would enable the residual biomass to be used in gas turbines. Biomass conversion to a clean essentially ash-free form, usually by gasification and purification, is necessary to obtain high efficiency. This paper reports results of detailed full-load performance modeling of cogeneration systems based on gasifier/gas turbine technologies. [ABSTRACT FROM AUTHOR]

Biomass gasification is a technology that transforms solid biomass into gas. A gasifier is capable of converting wood into a gaseous fuel that is fed into a gas motor. The gas motor controller regulates both the gas motor and the gas motor generator. In this paper 2 fuzzy logic controllers have been developed using speed and mechanical power deviations, and a neural network has been designed to tune the gains of the fuzzy logic controllers based on the operating conditions of the biomass-based electric power plant. [ABSTRACT FROM AUTHOR]

Biomass is a leading nonhydro resource of renewable energy. The gasifier heats the wood, the final result is a very clean burning gas fuel suitable for direct use in modern power systems such as gas turbines or diesel engines. In this paper a load is fed from these emergency electric units. [ABSTRACT FROM AUTHOR]