scholarly journals Voltage Recovery Control Techniques of Grid Connected Variable Speed Wind Turbines at a Short Circuit

2019 ◽  
Vol 8 (2) ◽  
pp. 868-873
Keyword(s):  
Wind Turbine ◽  
Power Quality ◽  
Wind Turbines ◽  
Short Circuit ◽  
System Stability ◽  
Normal Operation ◽  
Pitch Control ◽  
Control Techniques ◽  
Voltage Recovery ◽  
Dynamic Slip

The documented investigation in this paper examines main power quality for wind turbines and its connection with the public grid. This main goal has been to investigate most popular type of wind turbines which are grid connected using doubly-fed induction generators (DFIG) at normal operation, as well as voltage control of these wind turbines after clearing a lines short circuit in the utility grid. This paper introduces the configuration of main portions of grid connected turbines, which have an importance in the wind power plants operation. It also proposes a new compact modeling of these wind turbines, which has a feature that the expressions of most plant portions are free of any complex or details that described in other past models. Most of last models are spotted on the normal operation of single wind turbines, without consideration of gird interaction faults. The proposed control techniques are new combined and concentrated on the voltage recovery, which plays very important role in the power quality and stability of wind turbines plants which are connected with the grid. Net simulation results show that the combination of pitch control and dynamic slip control could to have power system stability efficiently, and restore the voltage to its normal condition. A simulation of wind turbine using pitch control and dynamic slip control are developed by the simulation program is called power system computer aiding design (PSCAD) and carried out the stability investigations respecting to short circuit in external power lines system. After clearing of the fault, the recovery of voltage at the terminals of wind turbine should to rebuild, then the wind power turbine should going to its normal case. Control of the pitch angle or generator slip can adjusting the aerodynamic torque and the electromagnetic torque at the turbine which can be help to recovery the voltage at the terminals of wind turbine. The results of case study simulation are proved that pitch and dynamic slip controls are methods to improve the recovery of voltage effectively and going to the system stability quickly, especially the combined controls of dynamic slip and pitch angel together.

Variable-speed Wind Turbines with Doubly-fed Induction Generators Part II: Power System Stability

2002 ◽  
Vol 26 (3) ◽  
pp. 171-188 ◽  
Author(s):  
Vladislav Akhmatov
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Short Circuit ◽  
Power Grid ◽  
System Stability ◽  
Variable Speed ◽  
Electrical Currents ◽  
Induction Generators ◽  
Doubly Fed Induction Generators ◽  
Doubly Fed

This article describes the second part of a larger investigation of dynamic interaction between variable-speed wind turbines equipped with doubly-fed induction generators (DFIG) and the power grid. A simulation model is applied for dynamic stability investigations, with the entire power grid subjected to a short-circuit fault. During the grid disturbances, the DFIG converter is found to be the most sensitive part of the wind turbine. Therefore the electrical currents are determined using the transient generator model. The converter action is crucial for wind turbine operation associated with such disturbances, especially regarding tripping or uninterrupted operation.

scholarly journals Research on Transient Power Quality of Large-capacity Electric Arc Furnace

2021 ◽  
Author(s):  
Liu Yang ◽  
Qinyue Tan ◽  
Di Xiong ◽  
Zhengguang Liu
Keyword(s):  
Power Quality ◽  
Reactive Power ◽  
Short Circuit ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Normal Operation ◽  
Arc Furnace ◽  
Three Phase ◽  
Transient Power Quality

The overrun of transient power quality index caused by the large-capacity electric arc furnace (EAF) has become a prominent problem affecting the safe and stable operation of the power system. (1) In this paper, the relationship between arc furnace volt-age and current is derived based on the different stages of arc combustion, and the random variation of chaotic phenomenon of the arc voltage are simulated. Established an EAF model suitable for the study of transient power quality problems. (2) Take 50t AC EAF as an example to analyze the reactive power impact and the influence on the point of common coupling (PCC) voltage caused by the three-phase short circuit of the electrode. The results show that the experimental results are consistent with the theoretical analysis, verifying the correctness and effectiveness of the model. (3) When the three-phase short-circuit occurs, the reactive power impact is nearly 6 times that of normal operation, the short-circuit current is 2.66 times that of normal operation, and the effective value of the PCC voltage has dropped by 40.37%, which provides a theoretical basis for real-time compensation of impulsive reactive power and improvement of the transient power quality of the EAF.

scholarly journals Vibration Reduction Strategy for Offshore Wind Turbines

2020 ◽  
Vol 10 (17) ◽  
pp. 6091
Author(s):  
Haoming Liu ◽  
Suxiang Yang ◽  
Wei Tian ◽  
Min Zhao ◽  
Xiaoling Yuan ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Output Power ◽  
Wind Turbines ◽  
Reference Signal ◽  
Offshore Wind ◽  
Wave Load ◽  
Offshore Wind Turbines ◽  
Pitch Control ◽  
Simulation Results ◽  
Aerodynamic Torque

The operational environment of offshore wind turbines is much more complex than that of onshore wind turbines. Facing the persistent wind and wave forces, offshore wind turbines are prone to vibration problems, which are not conducive to their long-term operation. Under this background, first, how the wave affects the vibration characteristics of offshore wind turbines is analyzed. Based on the existing wave and wave load models, we analytically show that there exist fluctuating components related to the hydrodynamic frequency in the aerodynamic load and aerodynamic torque of offshore wind turbines. Simulation results based on a GH Bladed platform further validates the analysis. Second, in order to reduce the joint impacts of the wave, wind shear and tower shadow on the wind turbine, a variable pitch control method is proposed. The integrated tower top vibration acceleration signal is superimposed on the collective pitch reference signal, then the triple frequency (3P) fluctuating component of the wind turbine output power and the azimuth angle of each blade are converted into the pitch angle adjustment signal of each blade, which is superimposed on the collective pitch signal for individual pitch control. The simulation results show that the proposed pitch control strategy can effectively smooth the fluctuation of blade root flap-wise load caused by wind and wave, and significantly reduce the fluctuation of aerodynamic torque and output power of offshore wind turbines.

The Straight-Bladed Morphing Vertical Axis Wind Turbine

2016 ◽  
Author(s):  
David MacPhee ◽  
Asfaw Beyene
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Low Cost ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Vertical Axis Wind Turbine ◽  
Pitch Control ◽  
Control Schemes ◽  
Horizontal Axis Wind Turbines ◽  
Novel Concept

Blade pitch control has been extremely important for the development of Horizontal-Axis Wind Turbines (HAWTs), allowing for greater efficiency over a wider range of operational regimes when compared to rigid-bladed designs. For Vertical-Axis Wind Turbines (VAWTs), blade pitching is inherently more difficult due to a dependence of attack angle on turbine armature location, shaft speed, and wind speed. As a result, there have been very few practical pitch control schemes put forward for VAWTs, which may be a major reason why this wind turbine type enjoys a much lower market share as compared to HAWTs. To alleviate this issue, the flexible, straight-bladed vertical-axis turbine is presented, which can passively adapt its geometry to local aerodynamic loadings and serves as a low-cost blade pitch control strategy increasing efficiency and startup capabilities. Using two-dimensional fluid-structure action simulations, this novel concept is compared to an identical rigid one and is proven to be superior in terms of power coefficient due to decreased torque minima. Moreover, due to the flexible nature of the blades, the morphing turbine achieves less severe oscillatory loadings. As a result, the morphing blade design is expected to not only increase efficiency but also system longevity without additional system costs usually associated with active pitch control schemes.

scholarly journals A Simplified Morphing Blade for Horizontal Axis Wind Turbines

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Weijun Wang ◽  
Stéphane Caro ◽  
Fouad Bennis ◽  
Oscar Roberto Salinas Mejia
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Production ◽  
Turbine Blades ◽  
Wind Turbine Blades ◽  
Annual Average ◽  
Average Wind Speed ◽  
Pitch Control ◽  
Average Wind

The aim of designing wind turbine blades is to improve the power capture ability. Since rotor control technology is currently limited to controlling rotational speed and blade pitch, an increasing concern has been given to morphing blades. In this paper, a simplified morphing blade is introduced, which has a linear twist distribution along the span and a shape that can be controlled by adjusting the twist of the blade's root and tip. To evaluate the performance of wind turbine blades, a numerical code based on the blade element momentum theory is developed and validated. The blade of the NREL Phase VI wind turbine is taken as a reference blade and has a fixed pitch. The optimization problems associated with the control of the morphing blade and a blade with pitch control are formulated. The optimal results show that the morphing blade gives better results than the blade with pitch control in terms of produced power. Under the assumption that at a given site, the annual average wind speed is known and the wind speed follows a Rayleigh distribution, the annual energy production of wind turbines was evaluated for three types of blade, namely, morphing blade, blade with pitch control and fixed pitch blade. For an annual average wind speed varying between 5 m/s and 15 m/s, it turns out that the annual energy production of the wind turbine containing morphing blades is 24.5% to 69.7% higher than the annual energy production of the wind turbine containing pitch fixed blades. Likewise, the annual energy production of the wind turbine containing blades with pitch control is 22.7% to 66.9% higher than the annual energy production of the wind turbine containing pitch fixed blades.

scholarly journals Modelling Types 1 and 2 Wind Turbines Based on IEC 61400-27-1: Transient Response under Voltage Dips

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4078 ◽  
Author(s):  
Tania García-Sánchez ◽  
Irene Muñoz-Benavente ◽  
Emilio Gómez-Lázaro ◽  
Ana Fernández-Guillamón
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Distribution System ◽  
Power Plants ◽  
Short Circuit ◽  
Energy Resource ◽  
Weather Conditions ◽  
International Electrotechnical Commission ◽  
Voltage Dips

Wind power plants depend greatly on weather conditions, thus being considered intermittent, uncertain and non-dispatchable. Due to the massive integration of this energy resource in the recent decades, it is important that transmission and distribution system operators are able to model their electrical behaviour in terms of steady-state power flow, transient dynamic stability, and short-circuit currents. Consequently, in 2015, the International Electrotechnical Commission published Standard IEC 61400-27-1, which includes generic models for wind power generation in order to estimate the electrical characteristics of wind turbines at the connection point. This paper presents, describes and details the models for wind turbine topologies Types 1 and 2 following IEC 61400-27-1 for electrical simulation purposes, including the values for the parameters for the different subsystems. A hardware-in-the-loop combined with a real-time simulator is also used to analyse the response of such wind turbine topologies under voltage dips. The evolution of active and reactive powers is discussed, together with the wind turbine rotor and generator rotational speeds.

The Modeling and Simulation of Wind Turbines and the Design of Pitch Control System

2011 ◽  
Vol 347-353 ◽  
pp. 2323-2329
Author(s):  
Zhi Chao Lan ◽  
Lin Tao Hu ◽  
Yin Xue ◽  
De Liang Zen
Keyword(s):  
Control System ◽  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Pitch Angle ◽  
Active Power ◽  
Internal Model Control ◽  
Pitch Control ◽  
Constant Pitch ◽  
Model Control

An increasing number of large wind turbines with a variable-speed variable pitch control mechanism are developed to improve the response speed of wind turbines and get maximum active power .Designing a reasonable pitch control system requires both a good control scheme and a more accurate wind turbine model. Base on the analysis of wind turbines’ principle, a local linearization model of wind turbine is built by using linearization method of small deviation in this paper. The model’s inputs are the data of wind speed and pitch angle, and the output is the active power. The accuracy of the model is verified by studying the active power output of wind turbine under different circumstances in which the pitch angle changes with a constant wind speed and the wind speed changes with a constant pitch angle. At the same time, this paper provides pitch control program based on internal model control after analyzing the disadvantages of PID pitch controller. When the wind speed is beyond the rating, the active power can be limited reasonably around the power rating of wind turbines by adjusting the pitch angle.

Variable-Speed Wind Turbines with Doubly-Fed Induction Generators Part III: Model with the Back-to-back Converters

2003 ◽  
Vol 27 (2) ◽  
pp. 79-91 ◽  
Author(s):  
Vladislav Akhmatov
Keyword(s):  
Wind Turbines ◽  
Short Circuit ◽  
Practical Investigations ◽  
System Stability ◽  
Variable Speed ◽  
Induction Generators ◽  
Doubly Fed Induction Generators ◽  
Set Up ◽  
Doubly Fed ◽  
Short Circuit Fault

A model of the back-to-back converter is set up and implemented in the simulation tool PSS/E as a user-developed model. This model is applied with that of the doubly-fed induction generator (DFIG), described in previous parts of this work [parts II and I]. The latter models variable-speed wind turbines in power stability investigations. Subjected to a short circuit fault, there will be a risk of converter blocking, followed by tripping of the wind turbine [1, 3]. The main reasons of blocking are over-current in the rotor converter and over-voltage in the dc-link. The DFIG model, with representation of the back-to-back converter, results in (a) more accurate replication of the current in the rotor converter and (b) improved computation of the dc-link voltage. These improvements are compared with the model with representation of the rotor converter only. Hence, the DFIG model with representation of the back-to-back converters might be preferred, in practical investigations of power system stability, to models with representation of the rotor converter only.

Symmetrical Short Circuit Current Characteristics of Doubly Fed Induction Generator Wind Turbine with Crowbar Protection

2012 ◽  
Vol 512-515 ◽  
pp. 782-787
Author(s):  
Jia Jun Zhai ◽  
Bu Han Zhang ◽  
Kui Wang ◽  
Wen Shao ◽  
Cheng Xiong Mao
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Operating Characteristics ◽  
Doubly Fed ◽  
Crowbar Protection ◽  
Short Circuit Fault

Doubly fed induction generator (DFIG) is now becoming one of most widely used wind turbines in global market for wind power generation, due to its outstanding advantages. However, the DFIG is sensitive to grid faults. The DFIG will have to be removed from the grid if there’s no protection appliance in it. Therefore, the crowbar protection is widely used in the world for improving the low voltage ride-through ability of wind turbines. This paper analysed the operating characteristics and short-circuit current of DFIG under symmetrical short-circuit fault with respect to different sags to grid voltage, which on the basis of DFIG wind turbine with crowbar protection. And the expressions of short-circuit current under symmetrical short-circuit fault for DFIG were derived. The effectiveness of the expression was simulated in PSCAD/EMTDC.

Sign in / Sign up

Export Citation Format

Share Document