Grid-connected Wind Power Generation Research Articles

Enhanced control of grid-connected multi-machine wind power generation systems using fuzzy backstepping approaches

This research paper presents an approach for enhancing the performance of a multi-machine wind power generation system (WPGS) through the combination of nonlinear and intelligent control techniques. The suggested approach focuses on optimizing the WPGS, which utilizes permanent magnet synchronous generators (PMSGs) interconnected with the grid. To enable grid connection, a back-to-back configuration is employed for both the rectifier and inverter in a fifteen-switch configuration, with control achieved through pulse width modulation. The designed control algorithm is designed to effectively regulate the system and reduce the active and reactive power ripples. Initially, the WPGS model is provided. Subsequently, the fuzzy backstepping control (FBC) law is detailed, incorporating the Lyapunov stability technique. Fuzzy logic is used to adapt the gains in the backstepping approach, ensuring the control system can accommodate disturbances and system variations. As a result, this adaptive control approach enables optimal effusiveness of the entire system in both static and dynamic operational regimes. Experimental tests were conducted using MATLAB to compare the efficacy of the designed strategy against the traditional backstepping control approach. The obtained results demonstrated the robustness and effective reference tracking capabilities of the designed FBC approach, along with the complete elimination of speed overshoot across diverse wind conditions. These findings validate the designed control approach's effectiveness and superiority over the BC approach under varying conditions.

Review of the Analysis and Suppression for High-Frequency Oscillations of the Grid-Connected Wind Power Generation System

Review of the Analysis and Suppression for High-Frequency Oscillations of the Grid-Connected Wind Power Generation System

Investigating safety precautions for linking photovoltaic and wind power generation to the grid

The grid integration of renewable energy sources such as solar and wind power has received significant research attention, however, there remains a vast scope for exploration and improvement. Specifically, the discourse around relay protection and safety automatic devices in these power generation methods has been somewhat limited during the grid connection process. This article endeavors to investigate the technical obstacles encountered by photovoltaic and wind power grid protection mechanisms and crucial equipment, amidst the steady growth of renewable energys share in the power grid. This exploration is considered advantageous. The aim is to study and summarize existing research on protective measures and automation equipment for photovoltaic and wind power generation during grid connection, to promote technological innovation and development in this field. This paper critically assesses studies conducted so far on the topic of relay protection and automation hardware used in grid-connected solar and wind power generation, underscoring the significance of different protection techniques and their pivotal roles in ensuring system safety during grid connectivity. It then dives into the present obstacles and constraints that these technologies contend with. In conclusion, it suggests a few potential areas and anticipations for prospective research.

Backstepping Control of an AC/DC/AC Converter in a Grid Connected Wind Power System

The contribution of this paper is to study a nonlinear control approach known as the backstepping control method to manage reactive and active power using new parametric values for the grid connected wind power generation system. Specifically, the research focuses on a system containing a wind turbine system, a permanent magnet synchronous generator (PMSG), and a grid connected via AC/DC/AC converter. A comprehensive mathematical model for both the wind turbine system, PMSG, and the grid connected via AC/DC/AC converter was developed for this purpose. The Simulation results of the grid-connected wind power generation system are presented and analyzed to show the performance of the nonlinear backstepping control method. The characteristics of the response to variations in generator speed and the power injected into the grid show the highlight of the performance of the backstepping method, under varying wind conditions.

Advanced PLL structures for grid synchronization in distributed generation

The actual grid code requirements include specific demands for grid connected wind power generation facilities. The Transmission System Operators are specially concerned about the Low Voltage Ride Through requirements which are becoming more restrictive in terms of the admissible disconnection conditions, but also in the active/reactive power that wind farms should inject to the network under fault conditions to support the grid. Solutions based on the installation of STATCOMs and DVRs, as well as on advanced control functionalities for the existing power converters of wind power plants, have contributed to enhance their response under faulty and distorted scenarios, and hence to fulfill these requirements. However, in order to achieve satisfactory results with such systems it is necessary to count on accurate and fast grid voltage synchronization algorithms, able to work under unbalanced and distorted conditions. This paper analyzes the synchronization capability of three advanced synchronization systems: the DDSRF-PLL, the DSOGI-PLL and the 3phEPLL, designed to work under such conditions. In the following the different algorithms will be presented and discretized and finally their performance, as well as its computational cost, will be tested in an experimental setup controlled by a means of a TMS28335 floating point DSP.

Topology of Wind Power DC Collection Converter Based on Double Bus Structure and Its Power Balancing Control Strategy

Wind power collection technology is the key to grid-connected wind power generation. Compared with AC wind integration, DC wind power collection is more advantageous. Using a triple active bridge (TAB) converter as a submodule, this paper proposes a wind power DC converter topology and its control strategy for medium-voltage dc (MVDC) grid connection. The converter adopts a double bus structure, with the MVDC bus connected to the grid and the low-voltage dc (LVDC) bus handling the mismatched power. It has independent maximum power point tracking (MPPT) control, power balancing, and autonomous voltage balancing on the output side. The converter system is simulated and verified on the MATLAB/SIMULINK software platform. The simulation results show the effectiveness of the control strategy and the ability of the converter to operate stably under multiple conditions.

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.

Scenario of Wind Energy in India - A Review

The energy that's generated by the moving wind is named as "wind energy." It's abundantly available within nature. In India, grid-connected wind power generation has now gained a high level of attention and acceptability as compared to other renewable technologies available in the country. Many developed and developing countries are now captivated by wind energy to fulfil many important aspects such as irrigation and electricity generation in remote areas. It's a clean source of energy, which has upmost importance within the growing rate of industrialization, agricultural development, etc. India has the fifth-largest installed alternative energy capacity. India has about 7% alternative energy installations, and about 2–3% of the whole energy generation is from wind. This paper will describe India's wind generation potential as well as the global status of wind energy. The objective of this study is to look at the present developments that have been made in India in the field of renewable energy and to analyze the future of our country in this world.

Retraction Notice: Rearrangement of Electrical Distribution Networks With Optimal Coordination of Grid-Connected Hybrid Electric Vehicles and Wind Power Generation Sources

Retraction Notice: Rearrangement of Electrical Distribution Networks With Optimal Coordination of Grid-Connected Hybrid Electric Vehicles and Wind Power Generation Sources

Stability Enhancement of Grid-Connected Wind Power Generation System Using PSS, SFCL and STATCOM

The stability related issues may occur in a power system due to disturbances in generating or loading conditions, especially in the presence of distributed generation (DG) based on renewable energy resources (RERs). This paper proposes a novel strategy for the stability enhancement of a wind power generation system (WPGS) by using a combination of three devices, namely, a power system stabilizer (PSS), resistive superconductor fault current limiter (R-SFCL) and static synchronous compensator (STATCOM). The small signal (SS) stability of the test system is enhanced by selecting the best PSS type from the different types of PSS. An R-SFCL is used for improving the rotor angle and the frequency stability of the test system. Two indices, namely, transient stability index and sum of maximum deviations (SMD) index are introduced for determining the optimal locations of different sized R-SFCLs for increasing the rotor angle stability. The sensitivity index (SI) based on the power change between areas is applied for determining the optimal locations of different sized R-SFCLs for enhancing the frequency stability. Along with rotor angle and frequency stability, LVRT capability improvement of the wind farm using STATCOM is also considered. Finally, the combined effect of R-SFCL and STATCOM on the rotor angle and the frequency stability, for different fault locations, is also investigated for determining the optimal location of an R-SFCL in the presence of STATCOM. The results presented in the paper show that STATCOM affects both the number of feasible locations and the optimal locations that can be selected for different sized R-SFCLs for augmenting the rotor angle and the frequency stability of the system during faults. Moreover, it is pointed out that an optimal combination between the different sizes and the locations of R-SFCLs and STATCOM exists to enhance the overall stability of the test system under fault conditions.

Dynamic Performance Evaluation of Grid-Connected Hybrid Renewable Energy-Based Power Generation for Stability and Power Quality Enhancement in Smart Grid

Today’s stochastic grid system is experiencing huge voltage fluctuations, which is responsible for power quality issues in the smart microgrid network due to its intermittent nature as well as penetration of hybrid renewable resources. Thus, the dynamic performance evaluation and their control are essential to sustaining the stability of the grid network. A d-q controller mechanism is suggested to maintain the balance of the distributed generation network and grid side network. A dynamic control mechanism of voltage source converter (VSC) is presented in the MPPT-based wind power generating station, where an induction generator generates the power by the optimal control of the wind energy-based subsystem. The distributed hybrid generation (solar PV and wind) subsystem’s output terminal is linked to the DC bus bar’s common link via the VSC. A VSI is utilized to convert the desired DC power to alternating current power. To regulate and improve the performance of the proposed hybrid power generating systems (HPGS), a supercapacitor (SC) is used to smooth out the ripple on the distribution side in the power grid. Furthermore, the dynamic stability of grid-connected solar PV and wind power generation systems is investigated. This article also proposed an effective control scheme for the SC in HPGS under the influence of weak grid conditions. This article aimed to validate the efficiency of the VSI topology; a PI controller stability enhancement approach is used in a proposed grid system under various disturbance conditions. Finally, the simulation results and FFT-based power quality response analysis are validated through the effective utilization of an SC.

Design of Control Method for Improving Current Quality of Wind Power Grid-Connected Inverter

The problem of suppression of nonlinear random impulse disturbance in grid-connected wind power generation is studied in this paper. The mathematical model of grid side converter of wind power system is obtained by using Kirchhoff law. A feedback synchronization controller is designed to suppress the disturbance of current. With the help of Lyapunov stability theory, the effectiveness of the synchronization controller is verified. Further effectively restrain the nonlinear random disturbance caused by the current connected to the grid, so that the current generated by the wind turbine is synchronized with the current generated by the power grid. Finally, the simulation verification is carried out. The simulation results show that the effectiveness of the proposed control method.

Dual-timescale generation scheduling with nondeterministic flexiramp including demand response and energy storage

Increased grid-connected wind power generation results in net load with higher volatility as well as larger ramping requirements. It is becoming imperative to provide flexible ramping products (flexiramp) for better generation / load alignment and smoother wind power integration. This paper advocates a non-deterministic flexiramp modeling approach devised in a hybrid stochastic / deterministic dual-timescale framework. The latter uses a day-ahead chance-constrained scheduling formulation along with a deterministic real-time online rolling scheduling model, to facilitate the procurement of flexiramp products in the two timescales. Demand response and energy storage are implemented and quantified as additional flexiramp product. Flexiramp reserve is introduced, to ensure sufficient flexiramp capacity throughout the timescales. To reduce the wear and tear of generators and consider the operational and maintenance costs in the proposed framework, cycling ramping (cycliramp) cost is subsumed as a penalty in the day-ahead objective function. Simulations are carried out for the 24-bus and 118-bus systems. Numerical results highlight the efficacy of the proposed generation scheduling models, along with the impact of contemplating flexiramp and cycliramp cost components in the dual-timescale scheduling approach.

Retracted: Rearrangement of Electrical Distribution Networks With Optimal Coordination of Grid-Connected Hybrid Electric Vehicles and Wind Power Generation Sources

In this paper, a new model for distribution network rearrangement (DNR) with regard to plug-in electric vehicles (PEVs) is presented. The proposed model is a random model (random programming) in which scenarios corresponding to vehicle uncertainty are simulated by the Monte Carlo method. The distribution system was also mathematically modeled by an approximate linear model. This way of modeling helps us to derive a new design based on linear integer programming. The electricity market is considered to be the day-ahead electricity market. Uncertainties regarding the price of electricity as well as the load of the distribution network are also considered. The simulation results on a 24-bus distribution system showed that the proposed model has the required efficiency. Uncertainties related to PEVs are modeled by random programming using Monte Carlo Simulation (MCS). The DNR problem is formulated as a MILP problem. This problem is then solved by the Banders decomposition (BD) algorithm. Numerical results also showed that if the PEV is charged intelligently in the DNR issue, then the cost of purchasing electricity from above will be lower than in the case where the PEV is not controlled in a controlled way. We also see a different switching strategy in these two cases, which indicates that considering the electric vehicle in the DNR problem is inevitable. In addition, a method for rearranging distribution networks to transfer load from one feeder to another was presented. It has been observed that this reduces the load of high-capacity feeders well and causes the construction of new feeders to be delayed. It was also observed that rearrangement of the distribution network leads to a reduction in network losses. Also, with the help of rearrangement, the amount of interrupted load can be significantly reduced.

Research on Power Quality Based on Doubly-Fed Induction Wind Generator

The influence of grid-connected wind power generation system on power quality has always been a focus of researchers. Doubly-fed induction generators are the most widely used wind turbine generators in the wind power industry, and their impact on the power grid during power generation and grid connection has also received widespread attention. In this paper, based on the power quality problem of double-fed induction generators connected to the grid, three aspects of voltage fluctuation, flicker and harmonics are analyzed respectively, and the influence of this model on grid power quality is analyzed.

A Comprehensive Economic Benefit Evaluating Method of Grid-connected Wind Power Generation under Demand Response

The phenomenon of abandoning wind power in China is very severe. Promoting the demand side response management vigorously become the key measures in North China. Overall efficiency evaluation of the wind farm connected with grid under demand response is necessary to solve the problem. At the same time National Energy Board of China called for a full launch of the carbon emissions trading in 2017. The carbon-emissions reduction is conducive to both environmental protection and economic benefits increasing. This article analyses six aspects of economic efficiency and low carbon benefits of the impact on the system, including the wind power station construction, operation and maintenance, scheduling cost of demand response, generation benefit, peak-load following benefit and network loss improvement benefit. Taken low carbon trading regulations as the basis, the paper come up with the establishment of a comprehensive economic benefits model in carbon emissions trading mechanism with comprehensive economic benefits of the system. The overall test system is quantified through calculation, which proves the validity of the evaluation method.

Control Strategy of DC Link Voltage Flywheel Energy Storage for Non Grid Connected Wind Turbines Based on Fuzzy Control

The large-scale development of wind power is an important means to reduce greenhouse gas emissions, alleviate environmental pollution and improve the utilization rate of renewable energy. At the same time, large-scale non grid connected wind power generation theory avoids the technical difficulties of wind power integration [1]. However, due to the randomness and uncontrollability of wind energy, the output power of the wind power generation system will fluctuate accordingly [2]. Therefore, the corresponding energy storage devices are arranged in the non-grid-connected wind power generation system to ensure the power quality, and it has become the key to full utilization of renewable energy. In the case of wind speed fluctuation, the DC bus control strategy of the wind turbine is proposed in this paper. It can reduce the impact on the unit converter and the power load; this ensures safe and stable operation of non-grid connected wind turbines.

Stator Current Harmonic Reduction in a Novel Half Quasi-Z-Source Wind Power Generation System

The generator stator current gets distorted with unacceptable levels of total harmonic distortion (THD) because impedance-source wind power generation systems use three-phase diode rectifiers. The stator current harmonics will cause increasing losses and torque ripple, which reduce the efficiency and stability of the system. This paper proposes a novel half quasi-Z-source inverter (H-qZSI) for grid-connected wind power generation systems, which can reduce the generator stator current harmonics a great deal. When H-qZSI operates in the shoot-through zero state, the derivative of the generator stator current is only determined by the instantaneous value of the generator stator voltage, so the nonlinear relationship between generator stator current and stator voltage is improved compared with the traditional impedance-source inverter. Theoretically, it is indicated that the stator current harmonics can be reduced effectively by means of the proposed H-qZSI. Finally, simulation and experimental results are given to verify the theoretical analysis.

Real-Time Multiple Open-Switch Fault Diagnosis in Three-phase AC/DC PWM Converter for PMSG Based Grid-Connected Wind Power Generation System

This paper proposes a new multiple open-switch fault diagnosis method and faulty switch localization algorithm in three-phase AC/DC PWM converter for permanent magnet synchronous generator (PMSG) based grid-connected wind power generation system. In the proposed scheme, the open-switch fault is detected by using normalized three-phase RMS currents and faulty switch location is identified by using normalized three-phase RMS currents as well as average phase currents. Various kinds of fault may occur in AC/DC PWM converter, which decreases the generator output power and degrades the stability in wind power generation system. In this paper, multiple as well as single open-switch fault conditions are investigated. The proposed fault detection and faulty switch localization algorithms do not require additional sensors or hardware since they use only the information on measured phase currents. In addition, they are quite simple, cost-effective and easy to use. To verify that the proposed methods are effective to detect faults and to identify the faulty switches position, the simulation results under twenty-one cases of open-switch faults are presented on different operating conditions.

Indirect Control of a Doubly-Fed Induction Machine for Wind Energy Conversion

In this paper, a grid connected wind power generation scheme using a doubly fed induction generator ( DFIG) is studied. The aims of this paper are: The modelling and simulation of the operating in two quadrants (torque-speed ) of a DFIG, the analysis employs a stator flux vector control algorithm to control rotor current, the system enables optimal speed tracking for maximum energy capture from the wind and high performance active and reactive power regulation using the PI regulator. The simulation calculations were achieved using MATLAB ® -SIMULINK ® package. Lastly, the obtained results are presented, for different operating points, illustrating the good control performances of the system