Grid-connected Wind Turbine Research Articles

Transient stability analysis of a grid-connected type-4 wind turbine with grid-forming control during the fault

Thanks to the ability of the inertia provision and the voltage support, the virtual synchronous generator with reactive power control (RPC) is a promising solution among various grid-forming control schemes. This paper analyzes the transient angle stability of the grid-connected type-4 wind turbine with virtual synchronous generator and reactive power control strategy during the fault. By deriving the analytical criterion with the transient energy function, various key factors on the transient stability of the system can be revealed comprehensively and jointly. Additionally, the impacts of the integral coefficient of the RPC and the power reference switching delay on the transient stability are also analyzed by plotting the phase portraits of the derived third-order large-signal model of the grid-connected wind turbine system. The analytical result can be helpful for the determination of the parameters of the grid-connected wind turbine in order to keep transient stable and keep connected with the grid during the fault. Finally, the robustness and the effectiveness of the theoretical analysis results are validated by the electromagnetic transient simulation in MATLAB/Simulink under various conditions.

Research on the Stability of Grid Connected Wind Turbine Combined with Energy Storage Power System Based on a New Wind Power Fluctuation Smoothing Strategy

Wind power equipped with an energy storage system (ESS) has been demonstrated as the best potential configuration for a rapid global energy transition in the future. In the traditional anti-pulse average filtering control strategy for controlling wind power fluctuations, the smoothing window interval is a constant value, when the forecast output power error is considerable, the fixed window interval width may not be able to meet the smoothing demand, so the traditional strategy has the problems of bad smoothing effect and high probability for power fluctuations exceeding the limit. We propose an optimization strategy for energy storage operation in this paper. Firstly, this strategy can dynamically adjust the window interval width according to the power prediction error, and find the optimal window interval width that makes the output power volatility satisfy requirements for grid connection, so as to achieve the effect of improving the smoothing effect. Secondly, by optimizing hydrogen storage systems operation to reduce the demand for storage system capacity, the odds of output power volatility exceeding the limits are reduced. The outcomes indicate that this new smoothing strategy is effective in improving the stability of the wind power grid connection.

Feasibility analysis of sustainable hydrogen production for heavy-duty applications: Case study of highway 401

Considering the environmental effects of the CO2 emissions in the transportation sector, it is vital to find alternate fuels which significantly mitigate the detrimental greenhouse gas emissions. Hydrogen, as a sustainable energy vector, could substantially decrease the CO2 emissions released by heavy-duty trucks. Development of such technology necessitates detailed planning, technical evaluations, and financial roadmaps. Therefore, regulating the grid sale and purchase prices is crucial to guarantee a successful hydrogen commercialization in the transportation sector. This study evaluates the sustainable framework of hydrogen refueling stations along Highway 401, Canada, employing grid-connected photovoltaics, wind turbines, electrolyzers, H2 tanks, and converters for various scenarios. A detailed GHG emission evaluation is conducted as per intensive programs and expenses from the central grid for all scenarios during the project lifetime. Sensitivity evaluation is conducted to evaluate the impact of grid price rates, capital cost multiplier, and PV output volatility on various technical and financial parameters. Integration of 1269 kW PV/31 WTs/58 ELC/220 kg H2 tank/901 kW converter under 10-truck scenario is determined to be the best system. The corresponding net present cost, levelized cost of hydrogen, and renewable fraction of the best solution are estimated to be M1.07$, $2.03 kg hydrogen, and 93%, respectively.

Concert Exploration of DFIG Grid-integrated MMC using Artificial Intelligence

The performance of grid-connected wind turbine systems that use a Doubly Fed Induction Generator (DFIG) is explored in this work. In the suggested configuration, two conversion stages are present. In the first step, Alternating Current (AC) voltage is changed into Direct Current (DC) voltage. At this point, the conventional two-level converter is implemented. The second stage involves the conversion of DC to AC using a five-level Modular Multilevel Converter (MMC). Voltage fluctuation is observed in the DC link. It is anticipated that the Fuzzy Logic Control (FLC) approach will be able to adjust the DC link voltage at the MMC of the second stage of conversion. For the purpose of the Pulse Width Modulation (PWM) system, the current controller is accountable for regulating the current signals and the reference signals. As a result, the PI Controller (PIC) is being evaluated for use in this function. Carrier-based Phase Disposition (PD) PWM is employed for MMC switch control. The proposed controllers’ performance is validated in Matlab/Simulink.

Influence of yaw control on flicker produced by wind turbines

IEC 61400-21-1 describes the procedure for measuring the flicker produced by a wind turbine. This is a complex procedure, as it involves the processing of voltage and current time series recorded in a grid connected wind turbine for its entire operating range. The standard assumes that the flicker produced by a wind turbine is related to wind variations and switching operations. The voltage and current signals recorded in a 2 MW Type III wind turbine located at a 32 MW wind power plant in Spain were used for the study. The work shows that most of the flicker produced by the wind turbine is due to the power consumption of the motor used by the yaw control system to orient the nacelle. These operations generate voltage changes whose amplitude is independent of the generated power. As the generated power increases, so does the number of yaw control operations and thus the flicker emitted. A simple analytical method is proposed to estimate the flicker produced by yaw control operations. The results confirm that incorporation of this strategy into the standard could considerably simplify the current flicker measurement procedure.

Improvement of Fault Ride-Through Capability of Grid Connected Wind Turbine Based on a Switched Reluctance Generator Using a Dynamic Voltage Restorer

This paper presents an improvement to the fault ride-through (FRT) capabilities for a wind turbine that employs a switched reluctance generator (SRG) using a dynamic voltage restorer (DVR). The wind turbine may be disconnected from the grid by voltage sag, swell, and faulty line voltage in the grid. To improve the stator voltage of an SRG during grid failures, the DVR is applied to inject voltage at the point of common coupling (PCC) into the grid voltage. A control strategy for the DVR based on fuzzy logic controller (FLC) is proposed in this study to improve the FRT capability and meet the grid codes while avoiding the disconnection of the turbine from the grid. MATLAB/SIMULINK simulation validated the effectiveness and performance of this approach under three test cases: balanced sag, unbalanced sag, and a single line-to-ground fault. In addition, the total harmonic distortions utilizing different controllers were compared in sag mode. Furthermore, the simulation results exhibited significant improvement in transient and steady-state response, thus verifying the effectiveness of the control strategy compared to traditional methods.

Technical Assessment of the Key LVRT Techniques for Grid-Connected DFIG Wind Turbines

As a key portion of renewable energy resources (RESs), wind energy penetration is rapidly deployed. The effects of grid faults on grid-connected wind turbines (WTs) are causing problems for wind energy producers. To meet the necessary requirements, additional resources and technical interventions are needed. One of these requirements is low voltage ride-through (LVRT) of doubly fed induction generator (DFIG)-based WTs. This means that DFIG-WTs must stay connected to the grid during transient grid faults and supply active and reactive power after the fault is cleared. Many techniques for improving the LVRT capability of DFIG-WTs have been developed and this paper examines them. The paper also evaluates how well they align with grid codes, and offers case studies and simulations of the selected key techniques. Lastly, this paper provides guidelines and suggested designs for the LVRT techniques for DFIG-WTs to ensure they meet local grid codes.

Design and DSP implementation in HIL of nonlinear observers for a doubly fed induction aero-generator

This paper reports on the conception and digital signal processor (DSP)-based hardware-in-the-loop realisation of a nonlinear observer for a grid-connected variable speed wind turbine using a doubly fed induction generator (DFIG). The objective of this work is to build some observation structure based on the extended Kalman filter (EKF), the sliding mode observer (SMO) and the adaptive model reference adaptive system (MRAS) observer to observe certain quantities of the wind power system connected to the electrical grid in order to reduce the complexity and the cost of the hardware, to achieve an increased mechanical robustness, to operate in hostile environments, to have a higher reliability and to ensure an unchanged inertia of the system. The proposed observers will be combined with robust nonlinear controls based on the backstepping approach to control the wind energy conversion system (WECS). The whole will be implemented on a TMS320F28335 DSP board. A comparative analysis of the proposed observers will be carried out. Through the results of the DSP implementation in hardware in the loop (HIL), we will prove that this improved combination increases the desired performance.

Modelbased Validation of Gridconnected DFIGbased Wind Turbine for Harmonic and Interharmonic Analysis

Modelbased Validation of Gridconnected DFIGbased Wind Turbine for Harmonic and Interharmonic Analysis

Artificial Intelligence and Machine Learning in Grid Connected Wind Turbine Control Systems: A Comprehensive Review

As grid-connected wind farms become more common in the modern power system, the question of how to maximize wind power generation while limiting downtime has been a common issue for researchers around the world. Due to the complexity of wind turbine systems and the difficulty to predict varying wind speeds, artificial intelligence (AI) and machine learning (ML) algorithms have become key components when developing controllers and control schemes. Although, in recent years, several review papers on these topics have been published, there are no comprehensive review papers that pertain to both AI and ML in wind turbine control systems available in the literature, especially with respect to the most recently published control techniques. To overcome the drawbacks of the existing literature, an in-depth overview of ML and AI in wind turbine systems is presented in this paper. This paper analyzes the following reviews: (i) why optimizing wind farm power generation is important; (ii) the challenges associated with designing an efficient control scheme for wind farms; (iii) a breakdown of the different types of AI and ML algorithms used in wind farm controllers and control schemes; (iv) AI and ML for wind speed prediction; (v) AI and ML for wind power prediction; (vi) AI and ML for mechanical component monitoring and fault detection; and (vii) AI and ML for electrical fault prevention and detection. This paper will offer researchers and engineers in the wind energy generation field a comprehensive review of the application of AI and ML in the control methodology of offshore and onshore wind farms so that more efficient and robust control schemes can be designed for future wind turbine controllers.

Stability Modeling and Analysis of Grid Connected Doubly Fed Wind Energy Generation Based on Small Signal Model

Stable wind power generation can ensure the quality of power transmitted by the grid. The application of large-scale grid-connected wind power systems will induce problems such as grid oscillation and frequency instability. In order to solve the problem of abnormal power system interaction caused by large-scale wind power access and improve the stability of grid-connected doubly-fed wind power generation, this paper proposes a stability modeling analysis of grid-connected doubly-fed wind power generation based on small signal model. First, the operating conditions of the grid-connected DFIG are analyzed, and the vector diagrams of the three operating conditions are given. When the grid-connected DFIG is in the super-synchronous working state, the sub-synchronous working state and the synchronous working state. According to the operating conditions of the grid-connected doubly-fed generators, the grid-connected doubly-fed wind power generation system is linearized. According to the relationship between the actual speed and the synchronous speed of the doubly-fed generator, the operating conditions of the doubly-fed generator are analyzed. By introducing the small-signal model, we analyze the small-signal of the grid-connected doubly-fed wind power generation system. The indirect current control circuit is used to perform reactive power compensation for grid-connected doubly-fed wind turbines. By calculating the reactive power loss of the grid-connected DFIG and the reactive power loss of the transmission line, the compensation capacity of the grid-connected DFIG is calculated. The transient voltage of the wind turbine is controlled by the rotor-side frequency converter, combined with the pitch angle control model. So far, this paper has realized the modeling analysis of grid-connected doubly-fed wind power generation stability. The simulation results show that the modeling analysis in this paper is reasonable for the small-signal analysis results of the stability of grid-connected doubly-fed wind power generation. In the rotor voltage simulation test, after the oscillation occurs for 1 s, the model starts to simulate and eliminate the fault. During the simulation period of 0.7 s∼1.0 s, the output voltage of the converter decreased to 168 V, and the voltage waveform did not fluctuate greatly after 1.0 s. The experimental results show that this method can improve the stability of grid-connected doubly-fed wind power generation.

Self-adapting PI controller for grid-connected DFIG wind turbines based on recurrent neural network optimization control under unbalanced grid faults

• Establish the MPPT with optimal speed ratio combined with hidden layer recurrent neural network (HLRNN) to obtain faster convergence. • Optimize the PI controller gains by using a hidden layer recurrent neural network. • Investigate the active power behavior in the presence of unbalanced grid faults. • Amelioration of the response time of the produced power compared with some other existing neural network schemes. This paper suggests the Hidden Layer Recurrent Neural Network (HLRNN) for controlling a wind power generation system based on a dual-fed induction generator. The generator's stator is connected directly to the electrical grid, while the rotor is linked through bidirectional converters. A PI controller-based Indirect Vector Control (IVC) scheme has been established to pilot the system. The PI regulator allows linear systems to perform well, but when subjected to physical variation conditions, the system's response becomes unstable, making the PI controller insufficient. This paper aims to ensure the PI controller gains self-adaptation regardless of the severity of the circumstances. The effectiveness of the proposed control is demonstrated by taking into account critical conditions such as wind speed changes, generator parameter variations, and asymmetrical faults in the grid. Furthermore, it is confirmed by the enhanced performance and the reduced oscillations during a voltage dip. The simulation results, achieved using MATLAB/Simulink, demonstrate that the response time is reduced to 1.8 (m s), the static error is minimized to 0.16%, and the overshoot is improved to 0.24% when compared to the IVC based on the PI controller and some existing neural network schemes.

Implantation, Operation Data and Performance Assessment of An Urban Area Grid-Connected Small Wind Turbine

Over the last few decades, and more prominently currently, many countries have launched and reinforced campaigns to reduce CO2 emissions from all human activities and, in the area of energy, promote energy generating technologies from low carbon, renewable sources, especially wind and solar. In recent years, this promotion of renewables can be seen in statistics as well as an extraordinary increase in plants using renewable sources. There is more activity surrounding the use of small devices installed close to consumers, such as small wind turbines (SWT). In cities, the best places to install SWT are tall buildings. The Institute of Energy and Environment (IEE-USP) has installed a 1.8 kW SWT on the University of São Paulo campus in São Paulo, Brazil. Even with low-magnitude winds at the site, the SWT installation was carried out to serve as a didactic apparatus and demonstration initiative of wind energy generation connected directly to the University’s electric grid, which already has other embedded renewable sources installed, namely photovoltaic and biogas plants. The turbine was placed on the roof of the existing High Voltage Laboratory building, leading to an operating height of 35 m. This paper presents previous local wind data measurements using a Lidar system, annual energy yield estimation calculations, and measurements, also bringing all implementation details. It reports and analyzes the operation and energy production data from three full operational years, from 2018 to 2020, discussing and concluding with further improvements of SWT from technical and economic aspects.

Construction of Power Supply Stability Control Model for Wind Connected Power Grid

There are many problems in the power supply stability control of wind power generation system, such as large fluctuations, poor control effect and so on. Therefore, a new stability control model of wind power grid connected is designed. Determine the DC grid connection mode when the wind farm is connected, convert the DC power into AC power through the converter station, and transmit it to the final AC system to realize the grid connection of wind power and power grid; According to the determined wind power access mode, calculate the mechanical operation power, mechanical torque and wind energy utilization coefficient collected by the wind turbine, complete the best collection of wind energy, and determine the shafting according to the mass block model of the wind turbine and generator, so as to realize the research on the mathematical model of wind power generation. By analyzing the power flow direction of the stator and rotor of the wind turbine generator set, the unstable state of the power supply voltage of the wind turbine generator set after grid connection is determined. The PV curve method is used to calculate the steady-state voltage stability of grid connected wind turbines, and a power supply stability control model based on the voltage stability of grid connected wind turbines is established. The nonlinear objective function method is used to optimize the critical point of power supply stability, calculate the maximum load and maximum power of the system, establish the static power supply and transient power supply stability model after wind power grid connection, and realize the power supply stability control research of grid connected wind power through the analysis of power supply characteristics. The experimental results show that the model is closer to the stability of the actual power supply in the test of improving the stability of the power supply, ensuring the quality of power supply, while the test results of the other two methods have large fluctuations. In the analysis of the change of power supply after grid connection, the experimental results obtained by the model are very close to the actual data values. Therefore, this method can effectively improve the performance of power system.

Research on Intelligent Fault Diagnosis of Wind Power Generation System Based on Data Fusion

With the consume of traditional petrifaction energy origin such as coal, matelote and physical gas and the increasingly serious question of entire warming, the penetration ratio of wind power in the energy economy continues to enhance. Wind farms are generally built-in areas with strong winds, tough working environments and a high probability of equipment failure. Faults on large grid-connected wind turbines will seriously influence the safety and stability of conventional strength grids. In addition, unplanned maintenance after a breakdown of wind turbines needs a lot of manpower and corporeal resources, which greatly decrease the efficiency of wind strength production and enhance production costs. Therefore, the key to solving the above problems is to quickly and efficiently identify fan faults, which in turn enables accurate troubleshooting. In the article, the malfunction diagnosis of intelligent wind power system based on data fusion is discussed, and it is found that the GBoost algorithm has high accuracy in detecting sensor gain error, sensor offset error and sensor standard error when the Gaussian white-to-noise ratio exceeds 45 dB. In addition, DBN has different diagnostic effects for different faults with different Gaussian noises, at 45 dB and 35 dB, each type of error varies slightly, and the dotted line varies; at 25 dB, each type of error has a large difference. The difference is large, indicating that at 25 dB, this type of error is more sensitive; comparing the state estimation effect makes DLSTM have good adaptability to time series, and also shows that DLSTM considers the system to be reliable enough, and can be obtained by data fusion of the parameters of each system. What is the state of its system, and then take corresponding measures.

Green hydrogen production: Analysis for different single or combined large-scale photovoltaic and wind renewable systems

Hydrogen is a promising energy carrier to provide sustainable energy use throughout the world. Researchers and policy-makers have focused on investigations in three areas of hydrogen-related technologies in the energy market: (1) alternative fuel production based on hydrogen and carbon dioxide; (2) hydrogen injection to the natural gas pipeline networks; (3) usage of hydrogen in transportation applications. One of the most important challenges facing hydrogen technology development is the production of green hydrogen, which can be achieved through water electrolysis coupled with renewable power generation. Although many studies have been conducted, there is still a need for further development, which requires open-source big data and models and standardization of the processes to compare different renewable-based hydrogen production systems. To fill this research gap, the performance of a grid-connected hybrid wind turbine and solar photovoltaic-based water electrolysis systems for large-scale green hydrogen production were investigated. The objective is to propose an accurate methodology to compare wind and solar systems, or hybrid ones, for green hydrogen production worldwide. A large dataset describing the hybrid wind turbine-photovoltaic hydrogen production in various locations was created by performing dynamic simulations using TRNSYS and analyzed using MATLAB and Excel. Several dimensionless indicators were employed and assessed for standardizing the performance evaluation procedure of renewable-based hydrogen production systems, including the electrolyser load portion satisfied by the wind turbine and photovoltaic, the generated wind turbine and photovoltaic energy portion supplied to the electrolyser load and the quantity of energy exported to and imported from the grid. The annual and monthly values of these indicators together with the total amount of green hydrogen production were estimated for 28 global locations. The procedure applied can be easily used to test small-scale applications like residential users or large-scale applications like industrial users, as well as for any hydrogen demand and climatic conditions.

Control and performance assessment of grid-connected PMSG-based wind turbine equipped with diode bridge rectifier and boost converter using three different control strategies

Control and performance assessment of grid-connected PMSG-based wind turbine equipped with diode bridge rectifier and boost converter using three different control strategies

Techno-Economic Analysis and Optimisation of Campus Grid-Connected Hybrid Renewable Energy System Using HOMER Grid

This study aimed to conduct a techno-economic performance and optimisation analysis of grid-connected PV, wind turbines, and battery packs for Syiah Kuala University, situated at the tip of Sumatra island in the tsunami-affected region. The simulation software Hybrid Optimisation Model for Electric Renewables (HOMER) was used to analyse and optimise the renewable energy required by the institution. The methodology began with the location specification, average electric load demand, daily radiation, clearness index, location daily temperature, and system architecture. The results revealed that the energy storage system was initially included in the simulation, but it was later removed in order to save money and optimise the share of renewable energy. Based on the optimisation results, two types of energy sources were chosen for the system, solar PV and wind turbine, which contributed 62% and 20%, respectively. Apart from the renewable energy faction, another reason for the system selection is cost of energy (CoE), which decreased to $0.0446/kWh from $0.060/kWh. In conclusion, the study found that by connecting solar PV and wind turbines to the local grid, this renewable energy system is able to contribute up to 82% of the electricity required. However, the obstacle to implementing renewable energy in Indonesia is the cheap electricity price that is mainly generated using cheap coal, which is abundantly available in the country.

Optimal Control of an Energy-Storage System in a Microgrid for Reducing Wind-Power Fluctuations

In conventional low-voltage grids, energy-storage devices are mainly driven by final consumers to correct peak consumption or to protect against sources of short-term breaks. With the advent of microgrids and the development of energy-storage systems, the use of this equipment has steadily increased. Distributed generations (DGs), including wind-power plants as a renewable energy source, produces vacillator power due to the nature of variable wind. Microgrids have output power fluctuations, which can cause devastating effects such as frequency fluctuations. Storage can be used to fix this problem. In this paper, a grid-connected wind turbine and a photovoltaic system are investigated considering the atmospheric conditions and wind-speed variations, and a control method is proposed. The main purpose of this paper is to optimize the capacity of energy-storage devices to eliminate power fluctuations in the microgrid. Finally, the conclusion shows that, in microgrids with supercapacitors, the optimal capacity of microgrid supercapacitors is determined. This method of control, utilizing the combined energy-storage system of the battery supercapacitor, in addition to reducing the active power volatility of the wind turbine and photovoltaic generation systems, also considers the level of battery protection and reduction in reactive-power fluctuations. In the proposed control system, the DC link in the energy-storage systems is separate from most of the work conducted, which can increase the reliability of the whole system. The simulations of the studied system are performed in a MATLAB software environment.

Lyapunov stability of grid-connected wind turbines with permanent magnet synchronous generator

Dynamic stability across a range of operating conditions and disturbances is an essential requirement in the control of wind turbines. To analyse and design for closed-loop stability, existing methods typically rely on the numerical evaluation of a small-signal model of the system around each operating condition. This approach, however, is an inefficient way to capture and shape dynamic behaviour over the wide ranges of operating conditions and parameter values arising in practical implementations. This work presents an analytic stability analysis for presents an analytic stability analysis for (PMSG) wind turbines. The proposed methodology, based on a Lyapunov function constructed from an analytic expression of the system Jacobian, enables the identification of regions of operation and parameter values for the wind turbine system within which its stability can be guaranteed. A feedback linearisation control strategy is adopted to deal with the nonlinear relationship between the generator speed and the DC-link voltage in the turbine back-to-back converter. The closed-loop response performance of the design based on the proposed methodology is compared to that of a conventional PI control design via simulation tests conducted on a 2 MW turbine model and a 5 MW (PMSG) reference turbine model on the FAST physics-based simulation tool developed by NREL.