Wind Energy Engineering

The introduction of wind energy has demanded the improvement of practices and methodologies used in the operation and planning of the Brazilian Interconnected Power Systems (BIPS). However, despite the significant participation of wind generation in the BIPS, the public dissemination of data on wind farms in the BPIS is still limited, in particular, the availability of anemometric records. To mitigate the effects of such a limitation, reanalysis data should be considered. In this article, we present the results of a study carried out using reanalysis data from MERRA-2 (global) to estimate capacity factors, on an hourly and monthly basis, in the Brazilian Northeast. Resumo: A introdução da energia eólica tem demandado o aperfeiçoamento das práticas e metodologias utilizadas na operação e no planejamento do Sistema Interligado Nacional (SIN). Contudo, apesar da participação expressiva da geração eólica no SIN, a divulgação pública de dados de aproveitamentos eólicos no SIN ainda é lim...

This paper addresses the impact of the first 50 MW wind farm project on the Dhofar network. The wind farm consists of 20×2.5 MW wind turbines and will be integrated into the 132 kV Dhofar network which is connected with the Maim Interconnected System through the Petroleum Oman Development grid. A model of the entire power system of Oman is developed for steady-state and dynamic studies using DIgSILENT software. Two types of generators are considered: doubly-fed induction generator and asynchronous generator with fully rated converter technology. Simulation results are presented including load flow, short-circuit, contingency and stability analyses. No adverse effects ware identified due to the wind farm connection to the Dhofar network. The currently applicable Grid Codes in most Gulf Cooperation Council (GCC) countries are focused on the connection of conventional synchronous generators but recently increasing number of non-synchronous renewable generators are being commissioned in...

Este artículo presenta un modelo estocástico para la simulación del comportamiento de la velocidad del viento en dirección horizontal. Además, se desarrollan modelos tanto para grandes como pequeñas escalas de tiempo. Estos modelos se obtienen a partir de una investigación documental en la literatura especializada. En el modelo a pequeñas escalas de tiempo se consideran cuatro componentes: promedio, rama, ráfaga, y turbulencia. El comportamiento de la componente turbulencia en la velocidad del viento fue modelado incluyendo una variable aleatoria. También se muestra el modelo para grandes escalas de tiempo, a partir de ciertas consideraciones para el modelo de pequeñas escalas de tiempo. Se presenta una discusión sobre la intensidad de la turbulencia y la longitud de escala de los fenómenos. Finalmente, el modelo fue validado mediante simulación en Matlab de un caso bien documentado.

This paper present a hybrid nonlinear control based on fuzzy sliding mode to control wind energy conversion system using a doubly fed induction generator (DFIG). Consiting of coupling fuzzy logic control and sliding mode control this technique is introduced to avoid the major disadvantage of variable structure systems, namely the chattering phenomenon. Effectiveness and feasibility of the proposed control strategy are verified by simulation results in Matlab Simulink.

The main issue when using pumped storage power plants is to increase their efficiency by reducing energy costs in the pump mode. This article proposes a diagram of a micro-hydro accumulative power plant with upper and lower reservoirs, a hydraulic turbine unit, a pumping unit and stepwise arranged hydraulic rams used to supply water from the lower reservoir to the upper one. This arrangement of hydraulic rams allows you to reuse the flowing water from them for feeding into the upper tank. The results of calculations and experimental studies show that the use of two stepwise arranged hydraulic rams allows to supply 20 ... 45% of the water from the lower tank to the upper tank, depending on the height of the lift without electricity consumption. According to the results of the experiments, an analytical dependence is obtained that approximates the process of feeding hydraulic rams of a certain flow of water to a selected lifting height. The energy characteristics of the design of a mi...

A mathematical model for a thermodynamically active wind turbine was presented in the author's previous papers, " A Fundamental Revision of Wind Turbine Design Theory " and " Corrected Momentum and Energy Equations Disprove Betz's Limit. " This paper expands on their fundamental concept, the intent of which was to correct the conventional wind turbine momentum theory which diverges from real flow and to correct the improperly used energy equation which ignores thermal energy and infers false limitations on wind turbine performance. The basis for this new theory is the corrected momentum and energy equations, along with the fundamental realization that the product of axial force normal to the turbine disc times the axial velocity should not be directly equated to the power extraction of a rotating turbine. In this paper it is mathematically shown how this term is representative of the power available but manifests itself as a shift in the internal energy of the flow field and is not necessarily the source of the energy extracted. This concept is contrary to conventional theories. A new relationship is derived for efficiency of the wind turbine which determines how much of this available power can be extracted by the system and it is shown how to increase both the available energy and the energy extracted.

The radioactive effect of nuclear power plants in accidental cases as well as carbon emission impact of fossil fuels have forced many countries to explore clean energy sources that are environmentally more suitable. As Bangladesh do not have good prospect in fuel cell, geothermal, tidal or wave resources, wind energy is an influential energy source in accordance with solar and biomass. In this paper, based on a2-parameter Weibull analysis method, wind characteristics and assessment of wind energy potential has been analyzed using the wind speed data of the period 2002-2011 at 10 m height of Cox's Bazar, the longest sea-beach located at the southeast of Bangladesh. From the calculation, it has been found that the monthly mean wind speed is ranged from 2.17 m/s in November to 2.90 m/s in April, the monthly values of the Weibull shape parameter (k) is ranged from 4.73 to 9.24, while the value of scale parameter (c) is ranged from 2.50 to 2.98 m/s and the monthly wind power density ...

Abstract: This study assessed the viability of wind electricity production at a local meteorological site in Sokoto State, Nigeria. 21 years monthly mean wind speed data at 10 m height obtained from the Nigerian meteorological station were employed to carry out monthly, seasonal, yearly and whole years wind profile characteristics. The data were subjected to the Weibull 2-parameter and other statistical analyses. The econometrics analysis of wind electricity generation from the site was also studied using three wind ...

Abstrak Ketahanan Energi adalah suatu kondisi terjaminnya ketersediaan energi, akses masyarakat terhadap energi pada harga yang terjangkau dalam jangka panjang dan tidak terpengaruh oleh gejolak regional maupun internasional. Menjadi negara maju, Indonesia harus dapat mendorong sektor industri sebagai penggerak perekonomian negara. Kebutuhan energi di sektor industri dan komersial diprakirakan tetap mendominasi untuk jangka panjang. Sebagai sektor penunjang pergerakan perekonomian, sektor transportasi juga terus meningkat.Konsumsi energi menurut jenis selama tahun 2000 sampai dengan 2015 masih didominasi oleh BBM (avtur,avgas,bensin,minyak tanah, minyak solar, minyak diesel, dan minyak bakar). Permasalahan energi yang terjadi saat ini adalah dibutuhkan alternatif baru yang dikenal sebagai energi baru terbarukan (EBT). Berdasarkan analisis dengan single exponential smoothing (SES) dengan menggunakan = 0.359680 dapat disimpulkan bahwa perencanaan energi perlu dilakukan supaya dapat me...

Wind turbine power upgrades have recently become a debated topic in wind energy research. Their assessment poses some challenges and calls for devoted techniques: some reasons are the stochastic nature of the wind and the multivariate dependency of wind turbine power. In this work, two test cases were studied. The former is the yaw management optimization on a 2 MW wind turbine; the latter is a comprehensive control upgrade (pitch, yaw, and cut-out) for 850 kW wind turbines. The upgrade impact was estimated by analyzing the difference between the post-upgrade power and a data-driven simulation of the power if the upgrade did not take place. Therefore, a reliable model for the pre-upgrade power of the wind turbines of interest was needed and, in this work, a principal component regression was employed. The yaw control optimization was shown to provide a 1.3% of production improvement and the control re-powering provided 2.5%. Another qualifying point was that, for the 850 kW wind tur...

The paper offers an analytical formulation of the two errors embodied in the momentum theory. The first one originates from to the use of the differential form of the axial momentum equation and the second one from the linearisation of the tangential velocity terms. Both errors are evaluated comparing the axial velocity at the disk as predicted by the momentum theories with that one obtained thorough a semi-analytical actuator disk method based on the exact solution of the flow. Several cases characterised by different values of the thrust and advance coefficient are analysed, and the range of validity of the momentum theories is discussed in depth.

Hydrogen, which has many advantages such as the highest energy density, environmental friendliness and safety, is considered as a universal energy carrier for the future. The present work is carried out with the aim of evaluating the hydrogen production from an alkali electrolyzer under various operating and geometric parameters.In order to achieve this aim, a test facility of the alkali electrolyzer is constructed and equipped with the necessary instrumentation. Effectsof concentration (0 - 45%) and temperature (20 - 70 o C) for the electrolyte, three different electrode shapes with same length, and five different materials on hydrogen production are experimentally evaluated. Experimental results, which are presented in graphical forms, revealed that concentration ratio of 26% for alkali electrolyte KOH achieves maximum hydrogen production rate. The electrolyte at temperature of 70 o C and input voltage of 11 V produces 190 cm 3 /min. Also, aluminum electrode of smooth cylindrical ...

Full-scale wind turbine is a mature technology and therefore several retrofitting techniques have recently been spreading in the industry to further improve the efficiency of wind kinetic energy conversion. This kind of interventions is costly and, furthermore, the energy improvement is commonly estimated under the hypothesis of ideal wind conditions, but real ones can be very different because of wake interactions and/or wind shear induced by the terrain. A precise quantification of the energy gained in real environment is therefore precious. Wind turbines are subjected to non-stationary conditions and therefore it makes little sense to compare energy production before and after an upgrade: the post-upgrade production should rather be compared to a model of the pre-upgrade production under the same conditions. Since the energy improvement is typically of the order of few percents, a very precise model of wind turbine power output is needed and therefore it should be data-driven. Fu...

Abstract— Voltage source converter (VSC) based high voltage DC (HVDC) transmission is viewed as the eventual fate of offshore power transmission. This paper goes for giving a solid VSC-HVDC transmission system design between offshore wind ranches and inland grids. In this paper, an extensive limit, low-speed flywheel energy storage system (FESS) in light of a squirrel cage inductance machine is connected in parallel with the VSC-HVDC at the grid side converter. The FESS is committed for surge power control (because of power flow unevenness amid fault) retention rather than being dispersed as resistive losses. Since the length of these surges is moderately little, it has been demonstrated that the flywheel can adequately relieve this issue. In this FESS converter model existed by using PI controllers in which will get good response of power leveling operation and under fault conditions of the systems. And FESS offshore wind farms using proposed controller Fuzzy logic controller. It h...

This paper aims to investigate the effect of climate conditions such as ambient temperature, humidity, pressure, sun radiation and pollution on sliced apples quality and drying time which are dried in an indirect forced cabinet solar drying (IFCSD) and open sun drying (OSD) systems. Both experiments were implemented at same place (Kabul, Afghanistan) and time. The IFCSD yield for saving time is 42.8 % which is more effective than drying in the OSD system. Simultaneously with the decreasing of sliced apple weight from 512.9 g down to 73.9 g, the water activity decreased from 0.955 down to 0.355 in the IFCSD system. For OSD system, the sample weight decreased from 512.6 g down to 78.4 g and its water activity from 0.955 down to 0.411. On the experiment day the average sun radiation was 571 w/m 2. The pressure drop between inlet and outlet of the dryer was 0.1 kPa. Different thin-layer mathematical models were investigated to identify the best model fitting the experimental data. The m...

This paper present a hybrid nonlinear control based on fuzzy sliding mode to control wind energy conversion system using a doubly fed induction generator (DFIG). Consiting of coupling fuzzy logic control and sliding mode control this technique is introduced to avoid the major disadvantage of variable structure systems, namely the chattering phenomenon. Effectiveness and feasibility of the proposed control strategy are verified by simulation results in Matlab Simulink.

Greenhouse gas emissions (GHGs) and their effects have been a matter of global concern over the past decade. With growing energy demands to support developing economies, there has been a challenge of harnessing and utilizing sustainable forms of energy to meet these demands and despite the effect of global warming and the problems associated with it, the use of fossil fuels is still increasing. This problem has negatively impacted the climate because the greenhouse gases evolved from burning fossils increase the concentration of carbon dioxide in the atmosphere and lead to global warming. This study investigates a method of channelling biogas for use as a sustainable energy source by using membrane technology. Initially, by observing the behaviour of biogas components as they travel selectively through the membrane support, findings showed that both fluid and structural properties have significant impact on the separation process. The next approach is to modify the membrane to obtai...

The radioactive effect of nuclear power plants in accidental cases as well as carbon emission impact of fossil fuels have forced many countries to explore clean energy sources that are environmentally more suitable. As Bangladesh do not have good prospect in fuel cell, geothermal, tidal or wave resources, wind energy is an influential energy source in accordance with solar and biomass. In this paper, based on a2-parameter Weibull analysis method, wind characteristics and assessment of wind energy potential has been analyzed using the wind speed data of the period 2002 -2011 at 10 m height of Cox’s Bazar, the longest sea-beach located at the southeast of Bangladesh. From the calculation, it has been found that the monthly mean wind speed is ranged from 2.17 m/s in November to 2.90 m/s in April, the monthly values of the Weibull shape parameter (k) is ranged from 4.73 to 9.24, while the value of scale parameter (c) is ranged from 2.50 to 2.98 m/s and the monthly wind power density is ...

To this day, much of modern wind turbine design and optimization is based on actuator disc theory which uses an incorrect solution to the momentum equation to derive results that diverge from realistic airflow. This along with the incorrect use of Bernoulli’s equation to equate the pressure differential across the turbine to the loss in kinetic energy results in the implication of false limitations on the maximum theoretical power extraction from a wind turbine. This paper derives new solutions for the momentum and energy equations which align with natural observations and empirical data and mathematically disprove Betz’s Limit. A thermodynamic model including rotation of the wind turbine wake is developed based on equations for isentropic flow. The key to extracting more energy from the wind is shown to be accomplished by increasing the rotational parameters of the slipstream with the naturally occurring extraction of thermal energy.

Optimal alignment of wind turbines to the wind direction is a crucial condition for the quality of power output and for the health of the turbines. Actually, bad alignment can cause degraded performances and dangerous loads that can affect, on the long run, the mechanical safety of the wind turbine. Supervisory Control And Data Acquisition (SCADA) systems are becoming widespread in modern wind energy technology because of the appreciable costs – benefits ratio. The common time scale of SCADA, yet, usually is not effective for misalignment diagnosis because the wind varies too rapidly. For this reason, misalignment is often diagnosed using ad hoc techniques as LIDAR-based or spinner anemometers. In the present work, it is shown that very useful indications for the diagnosis of misalignment can be obtained also from the SCADA data, without invoking expensive supplementary control techniques. The method is validated on the data set of a wind farm sited in Italy.

The worsening with age of technical systems performance is a matter of fact which is particularly timely to analyze for horizontal-axis wind turbines because they constitute a mature technology. On these grounds, the present study deals with the assessment of wind turbine performance decline with age. The selected test case is a Vestas V52 wind turbine, installed in 2005 at the Dundalk Institute of Technology campus in Ireland. Operation data from 2008 to 2019 have been used for this study. The general idea is analyzing the appropriate operation curves for each working region of the wind turbine: in Region 2 (wind speed between 5 and 9 m/s), the generator speed-power curve is studied, because the wind turbine operates at fixed pitch. In Region 2 1 ⁄2 (wind speed between 9 and 13 m/s), the generator speed is rated and the pitch control is relevant: therefore, the pitch angle-power curve is analyzed. Using a support vector regression for the operation curves of interest, it is observe...

Wind turbines commonly undergo non-stationary flow and, not rarely, even rather extreme phenomena. In particular, rough terrains represent a challenging testing ground, because of the combination of terrain-driven flow and wakes. It is therefore crucial to assess the impact of dynamic loads on the turbines. In this work, tower and drive-train vibrations are analyzed, from a subcluster of four turbines of a wind farm sited in a very complex terrain. The main outcome of the study is that it is possible to start from the analysis of wind conditions and interpret how wakes manifest in the vibrations of the turbines, both at structural level (tower vibrations) and at the drive-train level. This wind to gear approach therefore allows to build a connection between a flow phenomenon and a mechanical phenomenon (vibrations) and can be precious to assess loads in different working conditions.

Evolutionary Structural Optimization (ESO) is one of the rules in structural engineering which has received much attention by the researchers. Today, the reduction of construction cost and weight is an important issue in the structure design. The optimization phenomenon is pursuing to fulfill this objective. Thus, presenting a design which could be both safe and economic is of special significance. Despite the valuable researches which have been conducted on optimization of steel structures, the gap of research on ESO of wind bracing connection plates and other metal connections is sensible. The purpose of the present paper is to make an optimal design of these types of connections in the frames with convergent bracing. In this study, the software of Finite Element Method (FEM) of abaqus has been used to design the concentrically (convergent) wind bracing of connection plates based on optimization principles. The Von-Mises stress distribution contour has been presented for two statuses in different angles. In the designed bracing frame, dimensions and thickness of connection plate have been defined as the design variables and the design of optimization is compared with the design of ordinary status and the past works as well. This shows a noticeable reduction in the weight of the optimal designed plate in comparison with the ordinary design.

The ever-increasing popularity of finding alternative forms of renewable energy has seen an increased interest and utilization of wind energy. The objective of this research therefore, is to evaluate the environmental impacts and energy performance of wind farms. This study was operationalized in Jordan using a life-cycle assessment (LCA) method. The environmental impact is evaluated through lifecycle emissions that include all emissions during various phases of the project. The energy performance is illustrated by the energy indicators. The latter is the energy payback ratio (EPR) and the energy payback time (EPT). This study was conducted on a 38 Vestas V112 3-MW wind turbine located in the southern region of Tafilah in Jordan that is host to the country’s first wind farm. SimaPro 7.1 software was used as the modeling platform. Data for this study were collated from various sources, including, manufacturers, the wind turbine farm, and local subcontractors. A software database was ...

This paper present a hybrid nonlinear control based on fuzzy sliding mode to control wind energy conversion system using a doubly fed induction generator (DFIG). Consiting of coupling fuzzy logic control and sliding mode control this technique is introduced to avoid the major disadvantage of variable structure systems, namely the chattering phenomenon. Effectiveness and feasibility of the proposed control strategy are verified by simulation results in Matlab Simulink.

The world is now facing energy scarcity and climate change. In that context, renewable energy is gradually replacing fossil fuels. However, this source of energy has not been fully exploited. Some natural disasters bring a lot of energy but are not exploited, in particular, storms are among the heavyweights. In this paper, I propose a device for harvesting energy from wind, waves and especially storms. One such device is called a Stormbuoy. If used in practice and deployed on a large scale, the Stormbuoy will harvest significant amounts of energy from wind, waves and storms. This not only solved the problem of energy scarcity but also mitigated the destruction of the storm with humans.

Energy crisis in Pakistan is getting worst and worst with the passage of time due to the increasing gap between the supply and demand of electricity. One of the main reasons of this crisis is that in Pakistan maximum power plants are either hydel or thermal based. The recent increase in oil prices globally makes it difficult to provide cheaper electricity through thermal or furnace based power plants. Similarly setting up of new hydel power plants or maintaining the existing ones is an expensive affair. Keeping these factors in front it is the right time to find out viable alternate solution of power generation so that power crises in the country can be tackled. Pakistan is blessed with ample water resources throughout the year but unfortunately more than 50% of this water is being wasted because of non-availability of proper storage facilities. In order to seek low cost solution to power generation these water resources can be utilized easily through the setting up of micro hydel p...