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The problem of using a steam generator plant, operating on the Rankine cycle, to utilize some of the thermal energy as part of the system for ensuring the thermal regime of a spacecraft is considered. The thermal energy released by the instrumentation equipment is removed to external radiators using loop heat pipes, after which it is radiated into outer space. Part of the heat is converted into electricity to maintain the functioning of on-board radio-electronic equipment. The work assessed the influence of a steam generator plant on thermal systems (with a preliminary solution of a system of thermohydraulic equations with characteristic initial-boundary conditions of loop heat pipes), its design parameters, such as the area of external radiators and the mass of the system, and conclusions are made about the feasibility of its use. This system for ensuring thermal conditions using loop heat pipes can be useful for energy-consuming unmanned spacecraft with low restrictions on the mass and size characteristics of the device. [ABSTRACT FROM AUTHOR]

A pitch-regulated wind turbine has an exclusive pitch activator for every single blade, and it is possible to send various pitch angle demands to each blade. They possess a controller to perform this task, and the problem of delay-dependent robust stability with polytopic-type uncertainties of these time-varying delay systems must be resolved. This paper deals with the dynamic output feedback robust stabilization of the large wind turbine generator in the presence of time-varying delay and polytopic uncertainty. Two critical assumptions are considered for the turbine model involving the model's parameters are uncertain, and the blade-pitch control input actuates by a time-varying unknown delay parameter. A set of intervals is considered for the uncertain and delay parameters, which are assumed to be given and known. Then, a novel algorithm is proposed to design a proper controller for this system based on the Lyapunov-Krasovskii functional approach. The proposed controller simultaneously compensates for the effects of both delay parameters and uncertain parameters. To validate the results in this study, two simulation examples are proposed considering different turbines to compare the performance of the designed controller with previously designed controllers. The results reveal the superiority of the proposed controller compared to the existing controller. [ABSTRACT FROM AUTHOR]

The unique goods from university is utilized to support micro, small, and medium firms in enhancing company performance. These items underline the existence of a hydroelectric power generation system, particularly a portable generator turbine, which is an analytical and new output at Andalas University. This is a low-cost radial turbine made from a centrifugal blower. Inventors and users will profit from it. Therefore, this study intends to establish the financial feasibility of a portable generator turbine and its technology/patent valuation, as well as market potential, by applying a business model. Explanatory Sequential Mixed-Method Design was employed. Quantitative and qualitative methodologies were employed to assess the business's financial viability and product marketability. Based on the financial analysis, the construction of a portable generator turbine was viable, and had the potential to be commercialized due to its affordable value propositions. After identifying the business model canvas, adjustments should prioritize Customer Relationships, Channels, and Key Partnerships. [ABSTRACT FROM AUTHOR]

With the continuous growth of energy demand, the advantages of nuclear power, such as high energy density, low emissions, and cleanliness, are gradually highlighted. However, the increasing capacity of the turbine generator in nuclear power plants has led to greater losses and critical heating issues. Designing an effective cooling system plays an important role in improving the rotor's heat dissipation ability, especially under the condition of limited rotor space. In this study, the cooling effects of the rotor using a radial straight-type cooling structure and a composited radial–axial–radial cooling structure are compared and analyzed for a 1555 MVA hydrogen-cooled nuclear turbine generator. Three-dimensional fluid thermal coupled models of the rotor with both cooling structures are established, and corresponding boundary conditions are provided. The models are solved using the finite volume method. The flow law of cooling hydrogen gas inside the rotor and the temperature distribution of various parts of the rotor are studied in detail. Compared with the radial straight-type cooling structure, adopting the composited radial–axial–radial cooling structure can reduce the average temperature of the rotor field windings by 4.5 °C. The research results provide a reference for the design and optimization of the rotor cooling system for large-capacity nuclear turbine generators. [ABSTRACT FROM AUTHOR]

The high potential for renewable energy in the North Sumatra region, especially the coast of the Belawan area, needs to be exploited properly. The design will be carried out to explore the potential in coastal areas by carrying out simulation models of microgrid systems and hybrid systembased electricity installations. The method that will be used is to find the accuracy of strategic location points by considering the weather around the plant. The aim of determining strategic and ideal microgrid installation location points is useful in building a reliable system when fluctuating climate conditions occur so that it will have a significant effect on energy balance and energy conversion. The potential for installation construction will be carried out with a hybrid system using power sources from photovoltaic (PV), wind turbines and diesel generators assisted by HOMER pro software. Real measurement results in the field were obtained for the installation of a hybrid-based microgrid system on PV with a DC output power of 618.80 W with measurements in sunny weather conditions, then the potential wind speed on the wind turbine reached 5 m/s and the potential use of a diesel generator reached 40% with a power output capacity 1 kW. [ABSTRACT FROM AUTHOR]

Aiming at the high accuracy and high robustness position control of servo pump control in the pitch system of a wind turbine generator, this paper proposes an active disturbance rejection controller (ADRC). The ADRC considers pitch angular velocity and acceleration limits. According to the kinematics principle of the pump-controlled pitch system, the relationship between the pitch angular velocity and acceleration limit and the displacement of the hydraulic cylinder is established. Through the method of theoretical analysis, the nonlinear relationship expression between pitch angle and hydraulic cylinder displacement is obtained, and the linearization of pitch angular velocity control is realized; the formula for b0 (the estimated value of the input gain of the system) of the pump-controlled pitch system is obtained by the method of modeling and analysis, b0 is the key parameter for the design of the ADRC; the stability of the controller parameters is proved through the stability analysis and simulation analysis, and the design of the self-immobilizing controller with pitch angular velocity and acceleration limitation is the completed ADRC design. Finally, a joint simulation platform of AMESim and MATLAB as well as a physical experiment platform of electro-hydraulic servo pump-controlled pitch control is constructed, and the effectiveness of the proposed control method is verified through simulation and experiment. The results show that compared with the unrestricted ADRC and PID, the velocity-acceleration-limited ADRC can effectively improve the control effect of the angular velocity and acceleration of the paddle, smooth the startup process, improve the safety of the system, and have better position control accuracy and anti-jamming ability. [ABSTRACT FROM AUTHOR]

This paper introduces an innovative approach, Deep Multiscale Soft-Threshold Support Vector Data Description (DMS-SVDD), designed for the detection of anomalies and prediction of faults in heavy-duty gas turbine generator sets (GENSETs). The model combines a support vector data description (SVDD) with a deep autoencoder backbone network framework, integrating a multiscale convolutional neural network (M) and soft-threshold activation network (S) into the Deep-SVDD framework. In comparison with conventional methods, such as One-Class Support Vector Machine (OCSVM) and autoencoder (AE), DMS-SVDD demonstrates improvements in accuracy (by 22.94%), recall (by 32%), F1 score (by 12.02%), and smoothness (by 39.15%). The model excels particularly in feature extraction, denoising, and early fault detection, offering a proactive strategy for maintenance. Furthermore, the DMS-SVDD demonstrated enhanced training efficiency with a reduction in the convergence rounds by 66% and overall training times by 34.13%. The study concludes that DMS-SVDD presents a robust and efficient solution for gas turbine anomaly detection, with practical advantages for decision support in turbine maintenance. Future research could explore additional refinements and applications of the DMS-SVDD model across diverse industrial contexts. [ABSTRACT FROM AUTHOR]

Reactive power compensation (RPC) is a big problem during power system operation. Parenthetically, capacitor allocation and sizing may be the only convenient solution for RPC of power systems. The loss sensitivity factor (LSF) is applied here for finding the optimum capacitor position. This paper presents quasi-oppositional fast convergence evolutionary programming (QOFCEP), fast convergence evolutionary programming (FCEP), and evolutionary programming (EP) for the optimum location and sizing of shunt capacitors in the isolated microgrid (MG) for minimizing total real power loss throughout the day with and without the demand response program (DRP). The 33-node, 69-node, and 118- node isolated MGs have been studied to authenticate the efficacy of the suggested approach. Each MG includes small hydro power plants (SHPPs), solar PV plants (SPVPs), wind turbine generators (WTGs), diesel generators (DGs), and plug-in electric vehicles (PEVs). [ABSTRACT FROM AUTHOR]

This paper proposes a multi-objective H2/H ∞ maximum power tracking control of a variable speed wind turbine to minimize the H2 tracking error and ensure the H ∞ model reference-tracking performance, simultaneously. The optimal condition is obtained via a boost converter use, which adapts the load impedance to the wind turbine generator. Thus, based on the fuzzy T-S model, a multi-objective Maximum Power Point Tracking (MPPT) controller is developed, ensuring maximum power transfer, despite wind speed variation and system uncertainty. To specify the optimal trajectory to follow, a TS reference model is proposed taking as input the optimal rectified DC current. The conditions of stability and stabilization are expressed in terms of linear matrix inequality (LMI) for uncertain and disturbed T-S models leading to determining the controller gains. Finally, an example of MPP tracking applied to a Wind Energy Conversion System (WECS) illustrates the effectiveness of the proposed fuzzy control law. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach to estimating short-term production of wind farms, which are made up of numerous turbine generators. It harnesses the power of big data through a blend of data-driven and model-based methods. Specifically, it combines an Artificial Neural Network (ANN) for immediate future predictions of wind turbine power output with a stochastic model for dependability, using Hybrid Reliability Block Diagrams. A thorough state-of-the-art review has been conducted in order to demonstrate the applicability of an ANN for non-linear stochastic problems of energy or power forecast estimation. The study leverages an innovative cluster analysis to group wind turbines and reduce the computational effort of the ANN, with a dependability model that improves the accuracy of the data-driven output estimation. Therefore, the main novelty is the employment of a hybrid model that combines an ANN with a dependability stochastic model that accounts for the realistic operational scenarios of wind turbines, including their susceptibility to random shutdowns This approach marks a significant advancement in the field, introducing a methodology which can aid the design and the power production forecast. The research has been applied to a case study of a 24 MW wind farm located in the south of Italy, characterized by 28 turbines. The findings demonstrate that the integrated model significantly enhances short-term wind-energy production estimation, achieving a 480% improvement in accuracy over the solo-clustering approach. [ABSTRACT FROM AUTHOR]

It is common knowledge that wind energy is a crucial, strategic component of the mix needed to create a green economy. In this regard, optimizing the operations and maintenance (O&M) of wind turbines (WTs) is key, as it will serve to reduce the levelized cost of electricity (LCOE) of wind energy. Since most modern WTs are equipped with a Supervisory Control and Data Acquisition (SCADA) system for remote monitoring and control, condition-based maintenance using SCADA data is considered a promising solution, although certain drawbacks still exist. Typically, large amounts of normal-operating SCADA data are generated against small amounts of fault-related data. In this study, we use high-frequency SCADA data from an operating WT with a significant imbalance between normal and fault classes. We implement several resampling techniques to address this challenge and generate synthetic generator fault data. In addition, several machine learning (ML) algorithms are proposed for processing the resampled data and WT generator fault classification. Experimental results show that ADASYN + Random Forest obtained the best performance, providing promising results toward wind farm O&M optimization. [ABSTRACT FROM AUTHOR]

Vibration detection and display using magnification, or amplification, of high- speed video (Vibration Video Amplification, VVA) has been demonstrated to be a very useful tool. VVA has been challenged to produce useful results, especially when lower quality cameras are used, or if the component being tested involves relatively high frequencies (e.g. 200 Hz or higher). For these cases, detection of very low displacement levels is required for VVA to give useful results. This is because video methods detect displacement, not velocity, and vibration standards, such as ISO 20816 or HI 9.6.4, are based on velocity. For a given velocity acceptance level, the displacement associated with that velocity decreases in proportion to the vibration frequency. At relatively low frequencies such as 50 or 60 Hz, the resulting displacements are easily detectable. However, at higher frequencies such as gas turbine generator ("high spool") operating speeds, or pump or compressor blade passing frequencies, it is much more challenging. At 500 Hz for example, the detection capability required for vibration detection is roughly equal in terms of mils versus in/sec rms. Therefore, to detect 0.2 in/sec rms (5.1 mm/s), a displacement detection accuracy of 0.2 mil p-p (about 5 microns p-p) is required. This is achievable, but challenging for most cameras and scene evaluation software. Therefore, this paper will discuss methods to improve and evaluate the displacement resolution of VVA. The encouraging degree of precision that has been able to be achieved is reported [ABSTRACT FROM AUTHOR]

With the rapid expansion of offshore wind capacity worldwide, minimising operation and maintenance requirements is pivotal. Regarded as a low-maintenance alternative to conventional drivetrain systems, direct-drive generators are increasingly commonplace for wind turbines in hard-to-service areas. To facilitate higher torque requirements consequent to low-speed operation, these machines are bulky, greatly increasing nacelle size and mass over their counterparts. This paper therefore details the structural optimisation of the International Energy Agency 15 MW Reference Wind Turbine rotor through iterative Parameter and Topology Optimisation and the inclusion of additional structural members, with consideration to its mechanical, modal, and thermal performances. With temperature found to have a significant impact on the structural integrity of multi-megawatt direct-drive machines, a Computational Fluid Dynamics analysis was carried out to map the temperature of the structure during operation and inform a consequent Finite Element Method analysis. This process, novel to this paper, found that topologically optimised structures outperform parametrically optimised structures thermally and that integrated heatsinks can be employed to further reduce deformation. Lastly, generative design techniques were used to further optimise the structure, reducing its mass, deformation, and maximum stress and expanding its operating envelope. This study reaches several key conclusions, demonstrating that significant mass reductions are achievable through the removal of cylinder wall geometry areas as well as through the implementation of structural supports and iterative parametric and topology optimisation techniques. Through the flexibility it grants, generative design was found to be a powerful tool, delivering further improvements to an already efficient, yet complex design. Heatsinks were found to lower generator structural temperatures, which may yield lower active cooling requirements whilst providing structural support. Lastly, the link between the increased mass and the increased financial and environmental impact of the rotor was confirmed. [ABSTRACT FROM AUTHOR]

In this paper, an improved speed sensorless control method including the maximum power point tracking (MPPT) algorithm for grid-connected squirrel-cage induction generator (SCIG) wind turbine systems using modified reduced-order generalized integrator (ROGI)–frequency-locked loop (FLL) with the DC offset compensation capability is proposed. The rotor flux linkages are estimated by the modified ROGI-FLL-based observer, of which the inputs are d-q axis rotor EMFs, and hence the position of rotor flux linkage can be obtained directly based on these estimated flux linkages using the arc tangent function. The DC offset in the estimated rotor flux linkages, which can cause oscillations in estimated rotor speed, leading to oscillations in SCIG stator active power due to power signal feedback (PSF)-MPPT algorithm, can be significantly reduced using the DC offset compensators included in modified ROGI-FLL structure. Moreover, the negative effects of high-frequency components on the performance of the rotor flux linkage estimation can be remarkably mitigated owing to the excellent high-frequency component rejection capability of ROGI. The dynamic response analysis of the modified ROGI-FLL with DC offset compensators is provided as well. The feasibility of the proposed method has been demonstrated in comparison with dual SOGI-FLL with DC offset compensator-based existing method. [ABSTRACT FROM AUTHOR]

Purpose: Particle dampers are dynamic vibration absorbers that can be attached or inserted into a vibrating structure for broadband vibration attenuation. The particle damping technique is widely used across various industries for vibration attenuation because of its conceptual simplicity, cost-effectiveness, and suitability for harsh environments (Gagnon et al. in J Sound Vib, 2019. https://doi.org/10.1016/j.jsv.2019.114865; Lu et al. in Struct Control Health Monit, 2018. https://doi.org/10.1002/stc.2058). However, designing a particle damper for real-world applications is significantly challenging primarily due to the interaction among the numerous parameters that influence the damping effectiveness of a particle damper. Therefore, this contribution aims to experimentally investigate the particle dampers performance in the context of their designs. Methods: We introduce three different design variants, namely thin-walled cavity (TWC), thin-walled cavity with additional sheets (TWC-AS), and ring cavity (RC). Different strategies are detailed and evaluated in the current paper. Following the comprehensive study of various design variants at the laboratory scale, several tests were conducted on a real-scale wind turbine generator, subjected to real-world loading conditions. Additionally, the effect of particle damper size and its location for the structure on vibration attenuation has been studied. Results: Based on the experimental investigation, all these variants are effective in reducing the vibration amplitude of a structure. Furthermore, it has been found that for practical applications, particularly in the case of large-scale mechanical structures such as wind turbines, it is advisable to combine the most successful variants to design a particle damper. This approach can achieve significant vibration attenuation, and also minimize the additional mass of the granular material compared to a conventional particle damper. Conclusion: The findings from our experimental studies offer valuable insight into the design of particle dampers for large-scale hollow mechanical structures. [ABSTRACT FROM AUTHOR]

The supercritical CO2 (sCO2) power cycle could improve efficiencies for a wide range of thermal power plants. The sCO2 turbine generator plays an important role in the sCO2 power cycle by directly converting thermal energy into mechanical work and electric power. The operation of the generator encounters challenges, including high temperature, high pressure, high rotational speed, and other engineering problems, such as leakage. Experimental studies of sCO2 turbines are insufficient because of the significant difficulties in turbine manufacturing and system construction. Unlike most experimental investigations that primarily focus on 100 kW‐ or MW‐scale power generation systems, we consider, for the first time, a small‐scale power generator using sCO2. A partial admission axial turbine was designed and manufactured with a rated rotational speed of 40,000 rpm, and a CO2 transcritical power cycle test loop was constructed to validate the performance of our manufactured generator. A resistant gas was proposed in the constructed turbine expander to solve the leakage issue. Both dynamic and steady performances were investigated. The results indicated that a peak electric power of 11.55 kW was achieved at 29,369 rpm. The maximum total efficiency of the turbo‐generator was 58.98%, which was affected by both the turbine rotational speed and pressure ratio, according to the proposed performance map. [ABSTRACT FROM AUTHOR]

This paper suggests day-ahead scheduling of microgrid with and without demand side management considering hydrogen storage and plug-in electric vehicles. This is a highly constrained mixed integer nonlinear programming problem which is solved by using quasi-oppositional fast convergence evolutionary programming (QOFCEP) technique. The concept of the quasi-opposition-based learning is incorporated in fast convergence evolutionary programming (FCEP) to improve the efficiency and quality of the solution. QOFCEP employs quasi-oppositional based learning (QOBL) for population initialization and generation jumping. The studied microgrid comprises three diesel generators, one mini-hydro power plant, two wind turbine generators, two solar PV plants, one hydrogen storage system and plug-in electric vehicles. Simulation outcomes of the suggested QOFCEP technique have been compared with those obtained by FCEP and differential evolution (DE). It is seen from numerical results that the cost obtained with DSM is about 0.81% lower than the cost obtained without DSM. It is also seen that the cost obtained from QOFCEP is about 0.52% and 0.78% lower than the cost obtained from FCEP and DE, respectively. The suggested QOFCEP technique has the ability to bestow superior-quality solution. [ABSTRACT FROM AUTHOR]

The new power system is characterized by high penetration of renewable energy sources and a high proportion of power electronics (namely, double‐high). The grid‐forming control is an effective method to improve the grid‐connected stability of wind turbine generators (WTGs) in the "double‐high" grid. The control method based on the DC‐link voltage can effectively realize the grid‐forming control for WTGs. However, there is a disadvantage that the DC‐link voltage cannot be maintained at the given value. To address this, the grid synchronization mechanism of DC‐link voltage is explored and the specific implementation of a novel DC‐link voltage synchronous control applicable to full‐scale power conversion WTGs is proposed. Then, the boundary of the inertial coefficient is probed through the state‐space method. And a compensation control is proposed to enlarge the inertial response capability based on the mechanism of damping characteristics. Finally, the PSCAD/EMTDC simulation and RTLAB hardware‐in‐loop experiment show that the synchronization frequency can accurately map the grid frequency changes in real‐time under the premise that the DC‐link voltage remains constant. In addition, the inertial coefficient can be increased by more than five times with the compensation strategy, which can enhance the support capability of the WTGs to the power grid. [ABSTRACT FROM AUTHOR]

Downhole turbine generators (DHTG) installed within drill-string are susceptible to internal and external excitation during the drilling process, causing significant dynamic loads on bearings, and thereby reducing the bearing's service life. In this study, a finite element model of an unbalanced rotor-bearing system (RBS) of DHTG with multi-frequency excitations, based on the Lagrangian motion differential equation, is established. The responses of the RBS under different drill-string excitations in terms of time-domain response, whirl orbit, and spectrum are analyzed. For a constant rotor speed, lateral harmonic translational and lateral oscillation both transform the whirl orbit to quasi-periodic, while axial rotation only changes the response amplitude. Changing the duration of pulse excitation leads to different response forms. Then, the dynamic characteristics of the RBS supported by a squeeze film damper (SFD) are investigated. The results indicate that SFD effectively reduces the displacement response amplitude and bearing force near the critical speed. As the axial rotation angular velocity of the drill-string increases, the first critical speed and displacement response decrease, while the variation of lateral oscillation frequency and amplitude has limited impact on them. The established model provides a means for analyzing the dynamic characteristics of DHTG's RBS under drill-string excitations during the design stage. [ABSTRACT FROM AUTHOR]

In this study, we instrument the foundations and towers for two onshore shallow wind turbine generators (WTGs) to evaluate foundation response, quantify in-service loads, and assess the assumptions behind WTG foundation design calculations. Measurements of pressure at the soil–foundation interface, soil strain just below foundation level, and tower moments over long periods provide insights into the operational moments experienced by the tower and the load transfer mechanisms to the foundation system. The results of this study have implications for design practices in three distinct ways: (1) the assessment of rotational stiffness calculation assumptions, (2) the evaluation of pressure distribution used in the bearing capacity formulation, and (3) the estimation of tower loads used in the tower and anchor bolt design. Our observations show that the induced overturning moments correlate well with incipient wind speeds and directions and the associated soil pressure and strain responses. The overturning moments and the response parameters relate linearly within the spectrum of measured magnitudes. However, the pressure distribution across the foundation footprint does not monotonically increase or decrease with distance from the neutral axis of the foundation base (e.g., the pressure sensed at the foundation's center close to the foundation is between 1.5 and 2 times greater than the pressures sensed at the edges). In addition, the measured soil strain as a function of cyclic moments shows that the in-service cyclic shear strains are less than 1.4 × 10−5 (i.e., two orders of magnitude smaller than the assumed design strain level). Finally, the spectrum of cyclic moments follows a semilog trend, thus indicating that operational and nonoperational loads dominate the fatigue load spectrum. Our study suggests that adequately designed WTG foundations on competent fine-grained soil result in very low operational soil shear stresses and strains, which might indicate that the current design practices are too conservative in nature. Field measurements establish load spectrums for cyclic fatigue loads for the long-term operational conditions of WTGs. [ABSTRACT FROM AUTHOR]

This article investigates the construction of a wind power generator requiring the lowest possible cost. The proposed model is an Axial Flux Permanent Magnet (AFPM) Synchronous Machine, which contains two iron rotors and a coreless stator between them, constructed from resin. The scientific contribution relates to the coupling of economic and technical parameters, which will clarify the feasibility, i.e., a wind turbine construction capable of producing approximately 3.5 KW, using a simple mill and a generator of nominal rotor speed 100 rpm. Such studies are few in international literature and mainly concern low levels of rotor speed in relation to the produced output power. For the generator dimensioning, analytical equations are used, while the type and the dimensions of the magnets are determined, before the start of dimensioning. The authors carried out research in the international market, ending up with specific cost-effective magnets, while trying to adjust the remaining dimensions and materials of the machine based on these cost-effective magnets and the aforementioned nominal values of the generator. The machine, whose dimensions are derived by analytical equations, was simulated and analyzed using the Two-Dimensional Finite Element Method (2D-FEM) and the Three-Dimensional Finite Element Method (3D-FEM), for comparison purposes. Moreover, an economic analysis of the generator and its individual parts was conducted. Finally, a novel idea for reducing the total generator cost is proposed, by replacing the rotor disks with rings. The investigation revealed that analytical equations can predict with satisfactory accuracy the generator's parameters. In addition, as permanent magnets are the most expensive materials in the construction, their predetermination using low-cost magnets can reduce the construction cost. Finally, the proposed concept of a ring-shaped rotor instead of a disk rotor, provides a cost reduction of up to 20%. [ABSTRACT FROM AUTHOR]

Due to the unique structure of Permanent Magnet Flux Switching Generators (PMFSG), which involves the interaction of permanent stator magnets and rotor teeth, the generated cogging torque is higher compared to that of other permanent magnet machines, resulting in torque ripple, vibration, and noise. A well-designed machine structure reduces vibration and noise in PMFSG generators while also improving generator performance, machine power, and efficiency. According to related research, PMFSGs are an efficient and attractive solution for wind turbine generator applications and small-scale applications. The cogging torque in the PMFS generator is critical. In this study, a permanent magnet flux switching generator with a spoke arrangement, a toothed rotor with a single-layer slot, and a permanent magnet inside the stator with less cogging torque and higher output power were constructed. Simulations were carried out using the two-dimensional Finite Element Method (FEM) and optimized using the Taguchi method. The best model design will lower effective cogging torque and ripple cogging torque. Finally, the effectiveness of the proposed optimization approach was validated by comparing it to the base model. As a result, the suggested optimization method can be used to effectively design PMFS machines and other types of PM machines used in renewable applications. [ABSTRACT FROM AUTHOR]

As wind turbine generator systems become more common in the modern power grid, the question of how to adequately protect them from cyber criminals has become a major theme in the development of new control systems. As such, artificial intelligence (AI) and machine learning (ML) algorithms have become major contributors to preventing, detecting, and mitigating cyber-attacks in the power system. In their current state, wind turbine generator systems are woefully unprepared for a coordinated and sophisticated cyber attack. With the implementation of the internet-of-things (IoT) devices in the power control network, cyber risks have increased exponentially. The literature shows the impact analysis and exploring detection techniques for cyber attacks on the wind turbine generator systems; however, almost no work on the mitigation of the adverse effects of cyber attacks on the wind turbine control systems has been reported. To overcome these limitations, this paper proposes implementing an AI-based converter controller, i.e., a multi-agent deep deterministic policy gradient (DDPG) method that can mitigate any adverse effects that communication delays or bad data could have on a grid-connected doubly fed induction generator (DFIG)-based wind turbine generator or wind farm. The performance of the proposed DDPG controller has been compared with that of a variable proportional–integral (VPI) control-based mitigation method. The proposed technique has been simulated and validated utilizing the MATLAB/Simulink software, version R2023A, to demonstrate the effectiveness of the proposed method. Also, the performance of the proposed DDPG method is better than that of the VPI method in mitigating the adverse impacts of cyber attacks on wind generator systems, which is validated by the plots and the root mean square error table found in the results section. [ABSTRACT FROM AUTHOR]

Ice accumulation significantly impacts the mechanical properties of wind turbine blades, affecting power output and reducing unit lifespan. This study explores the icing characteristics and their effects on a 1.5 megawatt (MW) wind turbine blade's mechanical properties under various conditions, including wind speeds of 5 m per second (m/s) and 10 m per second, temperatures of −5 degrees centigrade (°C) and −10 degrees centigrade, and different liquid water contents, by using icing wind tunnel tests and structural statics analysis. The research reveals that ice predominantly forms in an irregular pattern on the leading edge of the blade. It is easy to produce corner ice and ice skating when the icing temperature and wind speed are higher, and the icing surface is rougher. When the other conditions remain unchanged, the decrease in temperature, an increase in wind speed, or a rise in liquid water content all lead to an increase in the average thickness of icing and the volume of icing at the leading edge, with the effect of the wind speed on the two being 147.8% and 147.9%, the effect of the liquid water content on the two being 39.9% and 53.5%, and the effect of the temperature on the two being 24.6% and 13.2%. The study finds that the blade tip experiences the maximum displacement in both iced and non-iced states, although the positions of peak equivalent stress and strain vary. The above study will also provide references for the design of new wind turbine blades and the anti-icing maintenance of wind turbine generator sets. [ABSTRACT FROM AUTHOR]

The compact internal structure of the bulb tubularturbine generator (BTTG) leads to poor ventilation and heat dissipation capability (VHDC). It will result in high- temperature faults and lead to losses for the hydro-power station, if the staff at the hydropower station fail to promptly regulate the external forced air cooling for effective heat dissipation. Thus, a specific and effective ventilation control strategy (VCS) is of utmost importance for the operation of the BTTG. In this study, the finite element method (FEM) was employed to solve the magnetic- flow-thermal coupled field of a 24-MW BTTG. The distribution characteristics of electromagnetic losses and their impact on the temperature field were revealed. Experimental validation was conducted to verify the effectiveness of the numerical results. The response surface methodology (RSM) was employed to design an experimental plan by building upon this foundation. Integrated with a multiobjective genetic algorithm (MOGA), an optimal relationship between ambient temperature, fan flow rate, and heating components' temperature was established. This relationship serves as the optimized ventilation control strategy for the BTTG. This research provides a theoretical framework for the formulation of operational guidelines to ensure the safe operation of generators. [ABSTRACT FROM AUTHOR]

Hybrid energy systems (HESs) are gaining prominence as a practical solution for powering remote and rural areas, overcoming limitations of conventional energy generation methods, and offering a blend of technical and economic benefits. This study focuses on optimizing the sizes of an autonomous microgrid/HES in the Kingdom of Saudi Arabia, incorporating solar photovoltaic energy, wind turbine generators, batteries, and a diesel generator. The innovative reinforcement learning neural network algorithm (RLNNA) is applied to minimize the annualized system cost (ASC) and enhance system reliability, utilizing hourly wind speed, solar irradiance, and load behavior data throughout the year. This study validates RLNNA against five other metaheuristic/soft-computing approaches, demonstrating RLNNA's superior performance in achieving the lowest ASC at USD 1,219,744. This outperforms SDO and PSO, which yield an ASC of USD 1,222,098.2, and MRFO, resulting in an ASC of USD 1,222,098.4, while maintaining a loss of power supply probability (LPSP) of 0%. RLNNA exhibits faster convergence to the global solution than other algorithms, including PSO, MRFO, and SDO, while MRFO, PSO, and SDO show the ability to converge to the optimal global solution. This study concludes by emphasizing RLNNA's effectiveness in optimizing HES sizing, contributing valuable insights for off-grid energy systems in remote regions. [ABSTRACT FROM AUTHOR]

With the rapid development of offshore wind power, large‐capacity wind turbine generators have put forward higher electrical and mechanical performance requirements for the cable. In this paper, kaolin/ethylene propylene diene monomer (EPDM) composites are prepared to investigate the effect of kaolin content on the electrical properties, mechanical properties and thermal conductivity of EPDM composites. The results show that appropriate amount of kaolin could synergistically improve the electrical‐thermal‐mechanical properties of EPDM. The composite with 30 wt% kaolin content achieves the best performance. The breakdown strength of kaolin/EPDM composites increases by 13.47%–72.19 kV/mm compared with that before modification, and the volume resistivity increases from 1013 to 1015 Ω·cm after modification. In addition, with the doping of kaolin, the tensile strength of composites significantly improves by over 500%–6.97 MPa, and the thermal conductivity of the composite is slightly improved. This work has important guiding significance for the development of insulation materials for cables. Highlights: Kaolin in EPDM scattered more uniform after modification.The addition of kaolin improves the electrical‐thermal‐mechanical properties of the composite.Kaolin/EPDM composites have promising applications. [ABSTRACT FROM AUTHOR]

Implementation of renewable energy sources (RESs) in power systems can reduce the dependence on fossil-fuel-based thermal power generation systems. At the same time, however, the system inertia decreases as synchronous generators decrease; this is crucial for maintaining the stability of the power system. Virtual inertia control (VIC) can regulate the output of an inverter-based resource (IBR) by increasing the inertia. For a wind turbine generator (WTG), output control factors such as pitch angle control and maximum power point tracking (MPPT) significantly affect the performance of the VIC. This paper theoretically clarifies that the pitch angle control contributes to improvements in the performance of the VIC and helps avoid a loss of operation of the WTG in frequency drop events by analyzing the movement of the operational point of the WTG based on the physical characteristic of the WTG and control characteristics of the pitch angle control and MPPT; an electromagnetic transient (EMT) simulation, performed to verify the analysis, is also presented. [ABSTRACT FROM AUTHOR]

Existing fault localization methods for power lines are not applicable to the collector line in onshore wind farms due to the dense access of complex power supplies. Therefore, a fault localization method based on equivalent zero‐sequence injection current (ZIC) is proposed for asymmetric phase‐to‐ground faults on collector lines. Firstly, the idea of load shifting is adopted to generalize the theory of equivalent injection current (EIC) to multi‐terminal and meshed lines. Then, considering features of the zero‐sequence network of wind farms, the EIC theory on two‐terminal and multi‐terminal lines is applied to zero‐sequence networks, and thus faulty areas, faulty sub‐lines, and fault distance can be determined. Attractively, the element correlation in node impedance matrices of zero‐sequence networks is derived from the network branch‐addition process, and the numerical characteristic of matrix elements is further revealed from the particularity of wind farms, based on which root‐mean‐square (RMS) calculation of ZIC can be improved to enable the localization without phasor measurement. Verification results prove that this proposed method can accurately realize the fault localization independent of wind turbine generators with a few measurement points, and the applicability of collector lines with line branches is also considered; additionally, only voltage RMS needs to be measured. [ABSTRACT FROM AUTHOR]

A distributed-power-generating source (DPGS) is intended to locally supply the increased power demand at a load bus. When applied in small amounts, a DPGS offers many technical and economic benefits. However, with large DPGS penetrations, the stability of the transmission system becomes a significant issue. This paper investigates the stability of a transmission system equipped with a DPGS at load centres supplying power to both a constant power (CP) and induction motor (IM) load. The DPGSs considered in the present study are microturbine and diesel turbine power generators (MTGS and DTGS), both interfaced with synchronous generators. The influence of an IM load supplied by the DPGS on small-signal stability is studied by a critical damping ratio analysis. On the other hand, time-domain indicators of the transient response following a short circuit are employed in the analysis. Further, a variance analysis test (VAT) is performed to determine the contribution of IM and CP loads on the system stability. The study revealed that large penetration levels of IM loads significantly affect the stability and depend on the kind of DPGS technology used. [ABSTRACT FROM AUTHOR]

With the evolution of renewable energies, many doubly fed induction generators (DFIGs) are being connected to the power grid, whose operation and grid‐connection stability have a major impact on the power grid. Currently, most studies focus on either modeling the mechanical–electrical section or the electrical‐grid section, and discussions have been limited to shaft oscillation or frequency coupling problems. In this study, a mechanical–electrical‐grid model of a DFIG was established to examine the impacts of wind speed and system control parameters on electrical damping and grid‐connection stability. The accuracy of the proposed model and validity of the analyses were verified using simulations. The following were observed: (1) In the case of changing wind speeds, the wind speed and the applied control model determine the shaft oscillation of DFIG, whereas the grid‐connected impedance on the rotor side is dependent on the wind speed. (2) At a constant wind speed, changes in control parameters under different control modes affect the dynamic characteristics of the drive train differently, whereas the grid‐connected impedance on the rotor side is primarily determined by the proportional gain of the inner/outer loop of the control system. The conclusions drawn from this study can further improve the safe and stable operation of DFIG wind power generation systems as well as their connection to the power grid. [ABSTRACT FROM AUTHOR]

Energy from river currents is one of the available renewable energy sources to produce electricity. An improvement in the efficiency of the horizontal axis current turbine is required for the successful utilization of this energy. This paper compares the power production of a horizontal axis current turbine and a turbine with two passive flow control attachments, the vortex generator, and the inserted tube. Firstly, the NACA S1210 hydrofoil shape has been selected. Then the variation of chord length and twist angle along the blade span has been determined. Finally, a 5-meter-diameter, three-bladed, horizontalaxis current turbine has been designed using the blade element momentum theory. The rotor has a maximum power coefficient and a maximum power of 0.47 and 42.71 kW, respectively, at the current speed of 2.1 m/s and a tip speed ratio of 6 when the hydrofoil with tubes has been chosen to design the horizontal axis current turbine. It has been proven that including vortex generators and tubes on the turbine can help increase power production by 9.8% and 14.7%, respectively. [ABSTRACT FROM AUTHOR]

A numerical investigation of floating-type substructures for wind turbine generators was conducted by using time-domain simulation. A Tri-Star floater for 8–10 MW generators, which was developed by Samsung Heavy Industries (SHI), was chosen as the floating substructure. To make the anchor system, catenary mooring lines, considering redundancy, were installed on the floater. The main sources of external force on the wind turbine generator are wind, waves, and currents. To consider severe environmental conditions, Design Load Cases (DLCs) 1.6 and 6.1 of the IEC guidelines (IEC 61400-3-1) were chosen. From the measured environmental data for the installation site, the main parameters for the simulation conditions were obtained. The tilt angle and horizontal movement of the floater and the mooring tension for the different mooring systems were checked. The response of the floater during the failure of the mooring was also studied, and the critical failure of the mooring was confirmed. During the failure of the mooring, the redundancy system worked well, in which the movement of the floater was constrained within the criteria for all scenarios. [ABSTRACT FROM AUTHOR]

Featured Application: This work has applications in the advancement of deep learning-based object detection using drones and the improvement of operations and maintenance strategies for wind energy farms. An effective way to perform maintenance on the wind turbine generator (WTG) blades installed in grid-connected wind farms is to inspect them using Unmanned Aerial Vehicles (UAV). The ability to detect wind turbine blade defects from these laser and RGB images captured by drones has been the subject of numerous studies. The issue that most applied techniques battle with is being able to locate different wind turbine blade defects with high confidence scores and precision. The accuracy of these models' defect detection decreases due to varying testing image scales. This article proposes the Res-CNN3 technique for detecting wind turbine blade defects. In Res-CNN3, defect region detection is achieved through a bipartite process that processes the laser delta and RGB delta structure of a wind turbine blade image with an integration of residual networks and concatenated CNNs to determine the presence of typical defect regions in the image. The loss function is logistic regression, and a Selective Search (SS) algorithm is used to predict the regions of interest (RoI) of the input images for defects detection. Several experiments are conducted, and the outcomes prove that the proposed model has a high prospect for accuracy in solving the problem of defect detection in a manner similar to the advanced benchmark methods. [ABSTRACT FROM AUTHOR]

In this paper, the types of wind turbines are listed and described, with the emphasis on horizontal-axis wind turbines. The parts are explained in more detail, the criteria for the selection of the wind turbine generator and the methods of managing the wind turbine are defined. In the Matlab/Simulink programming environment, a model of an electric power network with a wind farm was created, and the characteristics of the operation of wind turbines under normal and fault conditions were presented. [ABSTRACT FROM AUTHOR]

Load–frequency control for an islanded microgrid is very important. If a disturbance is applied to an islanded microgrid, the frequency of the system starts to fluctuate and these fluctuations must be damped by the load–frequency control system. The load–frequency control system uses different controllers to improve the damping of frequency fluctuations related to the islanded microgrid. In this article, the number of controllers used in the load–frequency control system related to an islanded two-area microgrid has been reduced, which means less complexity and less cost in the control structure of microgrids. Also, a new control method has been used in the load–frequency control structure related to the two-area microgrid, which is used to dampen the frequency fluctuations of each of the areas related to the two-area microgrid and to dampen the power deviations between the two microgrids. For this purpose, a hybrid Grey Wolf Optimizer and Pattern Search Algorithm (HGWO–PS)-based model predictive controller (new control method) is employed for load frequency control of an islanded two-area microgrid. The numerical simulations are conducted to verify the performance of the presented controller. Different scenarios such as changes in loads and/or variations in the generated power of the wind turbine generator and the photovoltaic system are studied in the MATLAB/Simulink environment, and the performance of the presented HGWO–PS-based MPC controller, the GWO-based MPC, and social-spider optimizer-based proportional–integral–derivative controller are compared using some criteria including the settling time, the peak overshoot and the peak undershoot. The results show the effectiveness of the presented controller. [ABSTRACT FROM AUTHOR]

In recent years, the extensive participation of turbine generator in deep peak regulation has caused significant damage to the rotor windings, which is rooted in the frequent and significant changes in the electrical load of the rotor, accompanied by thermal expansion and contraction, causing harm to the rotor insulation and stress fatigue of the metal conductor. Hydrogen, as the cooling medium for the rotor windings of turbine generators, has a direct impact on the windings temperature through its parameters. Starting from suppressing the harm of deep peak regulation on the rotor windings, the inhibitory effect of hydrogen parameter changes on the temperature of the gap‐pickup diagonal‐flow rotor is studied. A calculation model for the rotor temperature field of the turbo‐generator with gap‐pickup diagonal‐flow ventilation is established. The finite volume method is used to iteratively calculate the control equations in the fluid‐thermal‐solid coupling heat transfer problem, and the temperature field distribution of various components of the rotor under different excitation loads is obtained. On this basis, the effects of individual adjustment of hydrogen temperature and pressure, as well as the combined adjustment, on the temperature of the rotor windings are studied. Finally, a variable hydrogen parameter adjustment strategy is proposed for the operation of turbo‐generators under deep peak regulation conditions. To a certain extent, the winding temperature fluctuation can be suppressed, which provides a potential solution for the thermal stable operation of the rotor. [ABSTRACT FROM AUTHOR]

Monitoring turbomachines requires the pre-selection of several indicators used to process vibration signals. In this study, spectral analysis and orbital analysis were used to identify the nature of faults in a gas turbine generator set used to produce electricity. Using international vibration standards ISO 10816-4 and ISO 7919-4, vibration trend measurements, spectral analysis, and orbit analysis, it is possible to detect the severity of malfunctions and determine their nature, including unbalance, misalignment, rubbing, rotor bow, mechanical looseness, and shaft crack. According to this case study, the generator had a thermal imbalance which caused the rotor to bend, creating a complete annular rub between the shaft end cover and the fan of the excitation unit. Diagnostic features obtained by fast Fourier transform (FFT) related to mechanical imbalance have been explained. Also, orbit plots were effectively used to explain the unique nature of the fault. [ABSTRACT FROM AUTHOR]

Series compensation grids connected with type-3 wind turbine generator (WTG)-based wind farms have suffered numerous subsynchronous oscillation (SSO) events worldwide. For early alerting of SSO and effective development of protection and control strategies, it is critical to monitor and identify SSO accurately and quickly. Ambient data is continuously available, which is useful for online monitoring. This paper proposes an ambient data-driven SSO online monitoring method based on the Kalman filter (KF) combined with the multi-model partitioning filter (MMPF). The KF is utilized to fit the measured ambient data with an auto regressive (AR) model. Then, the damping factor (or damping ratio) and frequency in the SSO mode can be acquired by solving the roots of the characteristic polynomial corresponding to the AR model. Moreover, the MMPF is an effective model order selection method applied to the KF for better identification. The performance of the MMPF-KF method is demonstrated by simulations and real-time experiments. The results of case studies validate the effectiveness of the proposed method under various conditions. [ABSTRACT FROM AUTHOR]

Methane (CH4) is a greenhouse gas resulting from human activities, especially landfills, and it has many potential environmental issues, such as its major role in global warming. On the other hand, methane can be converted to liquid fuel or electricity using chemical conversion or gas turbine generators. Therefore, reusing such gases could be of great environmental and economic benefit. In this context, this study aims to estimate the emissions of methane gas from the landfills in Al-Hillah City, Iraq, from 2023 to 2070 and the producible electric energy from this amount. The estimating process was carried out using the Land GEM model and compared with traditional models. The obtained results demonstrated that the total estimated landfill methane emissions for 48 years are 875,217 tons, and the average annual methane emission is 18,234 tons based on a yearly waste accumulation rate of 1,046,413 tons and a total waste amount of 50,227,808 tons. The anticipated loads of methane gas can be utilized to generate about 287,442 MW/year of electricity from 2023 to 2070. In conclusion, the results obtained from this study could be evidence of the potential environmental and economic benefits of harvesting and reusing methane gas from landfills. [ABSTRACT FROM AUTHOR]

Wind energy is an increasingly important renewable resource in today's global energy landscape. However, it faces challenges due to the unpredictable nature of wind speeds, resulting in intermittent power generation. This intermittency can disrupt power grid stability when integrating doubly fed induction generators (DFIGs). To address this challenge, we propose integrating a Li-ion battery energy storage system (BESS) with the direct current (DC) link of grid-connected DFIGs to mitigate power fluctuations caused by variable wind speed conditions. Our approach entails meticulous battery modeling, sizing, and control methods, all tailored to match the required output power of DFIG wind turbines. To demonstrate how well our Li-ion battery solution works, we have developed a MATLAB/Simulink R2022a version model. This model enables us to compare situations with and without the Li-ion battery in various operating conditions, including steady-state and dynamic transient scenarios. We also designed a buck–boost bidirectional DC-DC converter controlled by a proportional integral controller for battery charging and discharging. The battery actively monitors the DC-link voltage of the DFIG wind turbine and dynamically adjusts its stored energy in response to the voltage level. Thus, DFIG wind turbines consistently generate 1.5 MW of active power, operating with a highly efficient power factor of 1.0, indicating there is no reactive power produced. Our simulation results confirm that Li-ion batteries effectively mitigate power fluctuations in grid-connected DFIG wind turbines. As a result, Li-ion batteries enhance grid power stability and quality by absorbing or releasing power to compensate for variations in wind energy production. [ABSTRACT FROM AUTHOR]

In this paper, based on the lift-type wind turbine, an adaptive double-drive lift–drag composite vertical-axis wind turbine is designed to improve the wind energy utilization rate. A drag blade was employed to rapidly accelerate the wind turbine, and the width of the blade was adaptively adjusted with the speed of the wind turbine to realize lift–drag conversion. The aerodynamic performance analysis using Fluent showed that the best performance is achieved with a blade curvature of 30° and a drag-type blade width ratio of 2/3. Physical experiments proved that a lift–drag composite vertical-axis wind turbine driven by dual blades can start when the incoming wind speed is 1.6 m/s, which is 23.8% lower than the existing lift-type wind turbine's starting wind speed of 2.1 m/s. At the same time, when the wind speed reaches 8.8 m/s, the guide rail adaptive drag-type blades all contract and transform into lift-type wind turbine blades. The results show that the comprehensive wind energy utilization rate of the adaptive dual-drive lift–drag composite vertical-axis wind turbine was 5.98% higher than that of ordinary lift-type wind turbines and can be applied to wind power generation in high-wind-speed wind farms. [ABSTRACT FROM AUTHOR]

Predicting the remaining useful life (RUL) of wind turbine generator rolling bearings can effectively prevent damage to the transmission chain and significant economic losses resulting from sudden failures. However, the working conditions of generator bearings are variable, and the collected run-to-failure data combine multiple working conditions, which significantly impacts the accuracy of model predictions. To solve the problem, a local enhancement temporal convolutional network with multistage degenerate distribution matching based on domain adaptation (MDA-LETCN) is proposed, extracting degradation features of wind turbine generator bearings and predicting their remaining service life in composite working conditions. This method first utilizes the local enhancement temporal convolutional network (LETCN) to extract time series features and used the K-means method for unsupervised division of the degradation status of rolling bearings. Secondly, the multistage degradation stage distribution matching (MDSDM) module is proposed to learn domain-invariant temporal features at different stages of bearing degradation under composite working conditions. Finally, the model is transferred to the target bearing using some health data that are easily available from the target bearing to solve the problem of individual differences in the degradation of generator bearings in different wind turbines. Comparative experiments were conducted using actual wind farm data, and the results showed that MDA-LETCN has high prediction accuracy. [ABSTRACT FROM AUTHOR]

Unstable vibrations in rotating machinery can stem from various causes, making it challenging to determine their origins. This research introduces the operational transfer path analysis method (OTPA) as a means to identify the causes of turbo generator vibrations. The model takes operational parameters, such as power and current, as input, and the vibration amplitude as output, to establish the source analysis model. To address the ill-conditioned input matrix, the singular value decomposition method is employed. By solving the transmissibility matrix and analyzing parameter contributions, the primary factors influencing vibration are identified. This method is applied to analyze the vibration sources in a 660 MW turbine generator unit. The generator experienced unstable vibration of unknown origin for a certain period. Operational transfer path analysis revealed that hydrogen pressure, hydrogen temperature, and bearing temperature significantly impacted the vibrations. Thermal imbalances and shaft misalignment in the generator rotor were inferred as the likely causes. Through adjustments to hydrogen pressure and temperature, the generator vibration was controlled until the next overhaul. Subsequent maintenance revealed partial blockage of the hydrogen ventilation holes, leading to rotor thermal imbalances. The feasibility of this method was confirmed. The objective of this study is to present an effective data-driven model for identifying the main influential parameters among numerous variables. This model can be applied to intelligent fault diagnosis in power generation units. [ABSTRACT FROM AUTHOR]

The wind turbine generators (WTG's) incapability of primary frequency support during system contingencies due to its decoupled nature from the system frequency causes profound integration and stability issues. The present study focuses on resolving such issues by enabling the WTGs to participate in long-term frequency support under the derated operation of WTGs. The deloading operation of WTGs can provide a specific reserve power margin by reducing its rotor speed, which can be utilized during system contingencies. In literature, linear and quadratic deloading techniques have been proposed but these fail to replicate the nonlinear characteristics of the WTG accurately, thereby making deloading ineffective. To effectively implement the deloading, this work uses a more-accurate higher-order Newton's interpolation polynomial (HNIP), to cope with the highly nonlinear characteristics of WTG. The proposed deloading approach is also augmented with a fuzzy-based intelligent supplementary control structure to handle the inherent and incorporated nonlinearities in WTG. The microgrid system, consisting of a conventional energy source with WTG, has been considered as system under investigation. The integral time absolute error for step wind profile and variable speed wind profile was found to be improved by 97.65% and 97.29%, respectively, with the proposed novel deloading technique with fuzzy-PID compared to PID. Further, to ensure the implementation viability of the proposed control scheme, real-time validation of the same is carried out on OPAL-RT 4510, having a Xilinx Kintex-7 FPGA board. It was found that for all the scenarios considered for real-time digital simulation purposes, the results unerringly matched with MATLAB/Simulink. [Display omitted] • Design and implementation of novel nonlinear deloading strategy for WTG. • Implementation of nonlinear fuzzy control structure as supplementary controller. • Real-time validation of proposed novel scheme on OPAL-RT 4510 for investigated MGS. [ABSTRACT FROM AUTHOR]

In this article, we have considered the state of development of high-power horizontal wind turbines. The most common wind turbines for operation with variable wind flow speed usually include a frequency converter to ensure the compatibility of generator with network. It leads to decrease in the efficiency of wind energy conversion system, while the use of direct connection of the generator to the axis of wind wheel leads to a significant increase in the weight and cost of the generator. The wind turbine with aerodynamic multiplication is an alternative to such systems. Its prototype with 750 kW power is manufactured and studied in Ukraine. This wind energy conversion system with the synchronous or induction generators offers the property to generate energy under optimal condition with invariable rotational speed of generator rotor within the wide range of variable speed of wind flow. In this case, it is not necessary to apply the frequency converter that contributes to increasing the efficiency and reducing the cost of wind turbine. As shown, the relative performances of mass, cost and efficiency of generators in proposed system comparatively to conventional one depend on the multiplication factor (i.e. ratio of the rotational speeds of wind turbine and generator). When the power of wind turbines is from 750 to 2500 kW, the multiplication factor is within the limits of 10.72 to 4.75. The theoretical and experimental study shows that the wind turbines with aerodynamic multiplication can be competitive as compared to conventional horizontal wind turbines. This article is aimed to comparative analysis of the quantitative and qualitative characteristics of the equipment used in high-power horizontal wind turbines with direct connection of generators to the axis of wind turbine and in wind turbines with aerodynamic multiplication. References 27, tables 1, figures 6. [ABSTRACT FROM AUTHOR]

The work reported in present study deals with the development of a novel stochastic model and estimation of parameters to assess reliability characteristics for a turbogenerator unit of thermal power plant under classical and Bayesian frameworks. Turbogenerator unit consists of five components namely turbine lubrication, turbine governing, generator oil system, generator gas system and generator excitation system. The concepts of cold standby redundancy and Weibull distributed random variables are used in development of stochastic model. The shape parameter for all the random variables is same while scale parameter is different. Regenerative point technique and semi-Markov approach are used for evaluation of reliability characteristics. Sufficient repair facility always remains available in plant as well as repair done by the repairman is considered perfect. As the life testing experiments are time consuming, so to highlight the importance of proposed model Monte Carlo simulation study is carried out. A comparative analysis is done between true, classical and Bayesian results of MTSF, availability and profit function. [ABSTRACT FROM AUTHOR]