scholarly journals An Enhanced Low Voltage Ride-Through Control Scheme of a DIFG based WTG Using Crowbar and Braking Chopper

2021 ◽  
Vol 16 (1) ◽  
pp. 61-67
Author(s):  
Kishan Jayasawal ◽  
Khagendra Thapa
Keyword(s):  
Reactive Power ◽  
Low Voltage ◽  
Turbine Generator ◽  
Grid Voltage ◽  
Low Voltage Ride Through ◽  
Control Scheme ◽  
Safe Limit ◽  
Grid Codes ◽  
Doubly Fed ◽  
Rotor Side Converter

The grid codes define low voltage ride-through (LVRT) as capability of wind turbine generator (WTG) to support the grid voltage by injecting reactive power and suppress the rise of DC-link voltage and inrush rotor current in the rotor side converter (RSC) of the doubly fed induction generator (DFIG) during a fault. Moreover, the rotor current increases significantly during severe disturbances if any protection schemes are not employed. Therefore, the protection schemes must be used to avoid the damage to the converter during a fault. This paper proposes an enhanced LVRT control scheme of a DFIG employing a crowbar in the RSC side and braking chopper across the DC-link capacitor. The DFIG is highly delicate to grid voltage fluctuation during a fault because the DFIG is directly linked to the grid via stator. During severe fault the crowbar regulates the rotor current within an acceptable range and the braking chopper discharges the DC-link capacitor via resistor within a safe limit. The proposed LVRT control scheme is performed for a 2.4-MW DFIG using a MATLAB/SIMULINK simulator. The results delineate that the proposed control scheme is able to rapidly decrease the rotor current and repress the escalation in DC-link voltage during a grid fault.

The Transient Characteristics Analysis of Doubly-Fed Induction Generator during the Asymmetric Voltage Sag

2014 ◽  
Vol 644-650 ◽  
pp. 3509-3514
Author(s):  
Jian Hua Zhang ◽  
Hao Ran Shen ◽  
Lei Ding ◽  
Chun Lei Dai
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Voltage Drop ◽  
Voltage Sag ◽  
Grid Voltage ◽  
Low Voltage Ride Through ◽  
Double Frequency ◽  
Characteristics Analysis ◽  
Doubly Fed

In order to analyze the control strategy of the low voltage ride through (LVRT) of DFIG during the asymmetric voltage sag, it is necessary to analyze the transient performance of a DFIG during the asymmetric voltage sag. In this paper, analyzed the influence of the asymmetric grid voltage to DFIG and the analysis method of the asymmetric voltage sag, and on the basis of positive and negative sequence mathematical model, analyzed the composition of stator output active and reactive power under the condition of asymmetric grid voltage. And built a DFIG asymmetric voltage drop simulation model of 1.5MW in MATLAB/Simulink, the simulation results shows that the stator voltage, current, active power and reactive power all present a double frequency ripple during the asymmetric voltage sag, consistent with theoretical analysis. It can provide theoretical basis for double-fed motor control strategy of asymmetric LVRT.

scholarly journals Dynamic Low Voltage Ride through Detection and Mitigation in Brushless Doubly Fed Induction Generators

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4461
Author(s):  
Ahsanullah Memon ◽  
Mohd Wazir Mustafa ◽  
Muhammad Naveed Aman ◽  
Mukhtar Ullah ◽  
Tariq Kamal ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Fuzzy Logic Controller ◽  
Low Voltage ◽  
Voltage Drop ◽  
Low Voltage Ride Through ◽  
Induction Generators ◽  
Doubly Fed Induction Generators ◽  
Reactive Current ◽  
Doubly Fed ◽  
Rotor Side Converter

Brushless doubly-fed induction generators have higher reliability, making them an attractive choice for not only offshore applications but also for remote locations. These machines are composed of two back-to-back voltage source converters: the grid side converter and the rotor side converter. The rotor side converter is typically used for reactive current control of the power winding using the control winding current. A low voltage ride through (LVRT) fault is detected using a hysterisis comparison of the power winding voltage. This approach leads to two problems, firstly, the use of only voltage to detect faults results in erroneous or slow response, and secondly, sub-optimal control of voltage drop because of static reference values for reactive current compensation. This paper solves these problems by using an analytical model of the voltage drop caused by a short circuit. Moreover, using a fuzzy logic controller, the proposed technique employs the voltage frequency in addition to the power winding voltage magnitude to detect LVRT conditions. The analytical model helps in reducing the power winding voltage drop while the fuzzy logic controller leads to better and faster detection of faults, leading to an overall faster response of the system. Simulations in Matlab/Simulink show that the proposed technique can reduce the voltage drop by up to 0.12 p.u. and result in significantly lower transients in the power winding voltage as compared to existing techniques.

Improved Control Strategy of Wind Turbine with DFIG for Low Voltage Ride through Capability

2014 ◽  
Vol 707 ◽  
pp. 329-332
Author(s):  
Li Ling Sun ◽  
Dan Fang
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Low Voltage ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Operating Characteristics ◽  
Low Voltage Ride Through ◽  
Doubly Fed ◽  
Rotor Side Converter ◽  
And Control

As the number of doubly fed induction generator (DFIG)- based wind-turbine systems continues to increase, wind turbines are required to provide Low Voltage Ride-Through (LVRT) capability, especially under the condition of grid voltage dips. This paper, depending on the operating characteristics of doubly-fed induction generator during grid faults ,deals with a protection and control strategy on rotor-side converter (RSC) to enhance the low voltage ride through capability of a wind turbine driven doubly fed induction generator (DFIG). The simulation and experiment studies demonstrate the correctness of the developed model and the effectiveness of the control strategy for DFIG-based wind-turbine systems under such adverse grid conditions.

scholarly journals Enhancement of Low Voltage Ride through Capability for DFIG based Wind Turbine with STFCL, DVR and Energy Storage System

2019 ◽  
Vol 8 (2) ◽  
pp. 2882-2886
Keyword(s):  
Wind Turbine ◽  
Reactive Power ◽  
Low Voltage ◽  
Storage System ◽  
Energy Storage System ◽  
Low Voltage Ride Through ◽  
Induction Generators ◽  
Collaborative Control ◽  
Switch Type ◽  
Doubly Fed

A Switch type fault current limiter in coordination with DVR is presented in this paper for Wind turbine generators that consist of doubly fed induction generators in order to full fill Low voltage ride through requirements in grid systems. The position of in-statement, the simulation and the methods for enhancement of LVRT functioning are represented. Collaborative control between the STFCL and a combination of Reactive power control and Inductance emulating control are used to enable the doubly fed induction generator to generate reactive power and ensure that the system remains safe even during faults in the grid. A different type of fault conditions are examined under both normal conditions and while the proposed system is attached.

Study of Reactive Power Compensation for Improvement of Low-Voltage-Ride-Through Capability of Wind Farm

2013 ◽  
Vol 724-725 ◽  
pp. 619-622 ◽  
Author(s):  
Chia Yu Hsu ◽  
Ta Hsiu Tseng ◽  
Pei Hwa Huang
Keyword(s):  
Wind Farm ◽  
Reactive Power ◽  
Low Voltage ◽  
Wind Farms ◽  
Static Synchronous Compensator ◽  
Low Voltage Ride Through ◽  
Induction Generators ◽  
Turbine Generators ◽  
Set Up ◽  
Doubly Fed

The main purpose of this paper is to study the enhancement of the Low-Voltage-Ride-Through (LVRT) capability of the wind farm with the installment of the Static Synchronous Compensator (STATCOM) and the Static Var Compensator (SVC). With more penetration of wind energy from on-shore and off-shore wind farms, utilities have been starting to set up the regulation requiring the wind turbine generators to remain connected to the grid when a fault takes place in the system which is referred to as Low-Voltage-Ride-Through (LVRT). A wind farm composed with doubly fed induction generators is used as the study system. Both the STATCOM and the SVC are utilized as the devices for enhancing the LVRT capability of the wind farm. The results are demonstrated for comparing the performance of the two devices in the improvement of voltage dynamic characteristics of the study system.

scholarly journals Improving low-voltage ride-through capability of a multimegawatt DFIG based wind turbine under grid faults

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohamed Nadour ◽  
Ahmed Essadki ◽  
Tamou Nasser
Keyword(s):  
Reactive Power ◽  
Low Voltage ◽  
Power Networks ◽  
Low Voltage Ride Through ◽  
Protection Circuit ◽  
Recovery Simulation ◽  
Doubly Fed ◽  
Crowbar Protection ◽  
Voltage Recovery

AbstractLarge integration of doubly-fed induction generator (DFIG) based wind turbines (WTs) into power networks can have significant consequences for power system operation and the quality of the energy supplied due to their excessive sensitivity towards grid disturbances. Under voltage dips, the resulting overcurrent and overvoltage in the rotor circuit and the DC link of a DFIG, could lead to the activation of the protection system and WT disconnection. This potentially results in sudden loss of several tens/hundreds of MWs of energy, and consequently intensifying the severity of the fault. This paper aims to combine the use of a crowbar protection circuit and a robust backstepping control strategy that takes into consideration of the dynamics of the magnetic flux, to improve DFIG’s Low-Voltage Ride Through capability and fulfill the latest grid code requirements. While the power electronic interfaces are protected, the WTs also provide large reactive power during the fault to assist system voltage recovery. Simulation results using Matlab/Simulink demonstrate the effectiveness of the proposed strategy in terms of dynamic response and robustness against parametric variations.

scholarly journals Improved Low Voltage Ride Through Capability of Wind Farm using STATCOM

2021 ◽  
Author(s):  
Miad Mohaghegh Montazeri
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Reactive Power ◽  
Low Voltage ◽  
Steady State Condition ◽  
Low Voltage Ride Through ◽  
Induction Generators ◽  
Turbine Generators ◽  
Wind Turbine Generators ◽  
Doubly Fed

Using power electronic converters with reduced capacity in doubly-fed induction generator (DFIG) based wind turbines make them vulnerable to over-current during grid disturbances. This thesis aims to analyze the behaviour of doubly-fed induction generators based wind farm for various timing schemes of crowbar deactivation and resumption of rotor side converter (RSC) in the case of grid fault. Also, usage of a static synchronous compensator (STATCOM) for the purpose of stabilizing the grid voltage after a three-phase fault is studied in this these. Moreover, finding minimum capacity of STATCOM which ensures low-voltage ride through (LVRT) of wind farm is studied. Finally, coordination of reactive power from wind turbine generators and STATCOM in steady-state condition is performed. All the results in this thesis show that STATCOM improves low voltage ride through (LVRT) capability of wind farm and assists for an uninterrupted operation of wind turbine generators during grid faults.

Study of Improving Low Voltage Ride - Through Capability of Doubly - Fed Induction Generator by Using DVR

2014 ◽  
Vol 607 ◽  
pp. 531-535
Author(s):  
Chen Jian ◽  
Ren Yong Feng ◽  
Hu Hong Bin
Keyword(s):  
Power System ◽  
Wind Power ◽  
Low Voltage ◽  
Dynamic Voltage Restorer ◽  
Grid Voltage ◽  
Low Voltage Ride Through ◽  
Voltage Drops ◽  
Dynamic Voltage ◽  
Wind Power System ◽  
Doubly Fed

with the increasing proportion of wind power in whole power system ,the influence between wind power system and grid become more and more seriously ,so it is great important to research how to keep the connection between the wind power system and grid when grid voltage drops .The paper presents a new method to realize the low voltage ride - through (LVRT) of DFIG by using dynamic voltage restorer (DVR). Once the grid voltage drops,DVR will be put into use and produce compensation voltage to keep the stator side voltage steady .And it also can stop operation after the fault resolution.The paper builds a simulation model of DFIG and gives simulation results on PSCAD/EMTDC platform .

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