scholarly journals Validating Response of AC Microgrid to Line-to-Line Short Circuit in Islanded Mode Using Dynamic Analysis

2019 ◽  
pp. 1-15
Author(s):  
Maruf A. Aminu
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Power Flow ◽  
Reactive Power ◽  
Short Circuit ◽  
Operating Mode ◽  
Superior Performance ◽  
Induction Generators ◽  
Bidirectional Power Flow ◽  
Control Regime

This paper is presented in an attempt to validate the dynamic response of a microgrid to line-to-line short circuit. The microgrid components include two identical Wind Turbine Generators (WTGs) tied to a 100MVA, 13.8kV utility via a Point of Common Coupling (PCC). The utility-microgrid testbed is modeled in SIMPOWERSystems® using two Doubly-Fed Induction Generators (DFIGs) in the microgrid side. While in islanded operating mode, line-to-line short circuit fault is applied at 6.0s and withdrawn at 8.0s, obtaining a 50.0s dynamic response of the system for different fault locations, under voltage and reactive power control regimes of the wind turbine controller. For measurement purpose, the absolute value of the stator complex voltage is transformed to  reference frame. Bidirectional power flow between the two feeders is established in the study. The study also confirms that the microgrid composed of DFIGs offer reactive power management capability, particularly by presenting superior performance when stressed under Q control regime than under V control regime. Finally, the response of the testbed to line-to-line short circuit has been validated and shown to be consistent with established short circuit theory.

Active & Reactive Power Control Of A Doubly Fed Induction Generator Driven By A Wind Turbine

2012 ◽  
pp. 190-197
Author(s):  
Srinath Vanukuru ◽  
Sateesh Sukhavasi
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Operating Conditions ◽  
Control Approach ◽  
Induction Generators ◽  
Major Disadvantage ◽  
Stator Flux ◽  
Doubly Fed ◽  
Stator Flux Oriented ◽  
Bidirectional Power Flow

Wind Energy is gaining interest now-a – days as one of the most important renewable sources of energy due to its ecofriendly nature. But the major disadvantage lies in variable speed wind generation and this paper gives a study on control of Wind driven doubly fed Induction Generators. The speeds above and below Synchronous speeds are obtained using a bidirectional power flow converter. By using this reactive power is controlled and hence the overall Power factor of system can be kept at unity under varying load conditions. . This paper presents simulation results of a Grid-connected DFIG. A switch-by-switch representation of the PWM converters with a carrier-based Sinusoidal PWM modulation for both rotor- and stator-side converter has been proposed. Stator-Flux Oriented vector control approach is deployed for both stator- and rotor-side converters to provide independent control of active and reactive power and keep the DC-link voltage constant. A 7.5 KW generator is designed and its effectiveness in controlling is verified in different operating conditions i.e. above and below synchronous speeds.

Variable Structure Fuzzy-PID Control for DFIG System

2011 ◽  
Vol 204-210 ◽  
pp. 1147-1150
Author(s):  
Le Peng Song ◽  
Zhi Ming Dong ◽  
Rui Zhang
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Control Strategy ◽  
Reactive Power ◽  
Variable Structure ◽  
Fuzzy Pid Control ◽  
Induction Generators ◽  
Wind Turbine System ◽  
Synchronous Reference Frame ◽  
Fuzzy Control Strategy

In order to most effectively utilize the wind energy and improve the eficiency of wind generation system，an optimum control strategy of doublyfed induction generators (DFIG) was proposed,which made the system operationfor both the maximum wind enemy captured below the rated wind speed．Based on the wind turbine characteristics and basic electromagnetic relationship of DFIG the mathematical models of the stator active power and reactive power of DFIG were derived to fulfill maximal wind energy capture and conversion．A dual-passage excitation fuzzy control strategy based on dynamic synchronous reference frame was applied to control the proposed optimal stator active and reactive power．The operational performan ces of the wind turbine system with DFIG with wind speed variation were analyzed an d compared by using Matlab/Simulink．The results show the correctness and feasibility of the proposed control strategy.

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 Techniques for Ensuring Fault Ride-Through Capability of Grid Connected DFIG-Based Wind Turbine Systems: A Review

2021 ◽  
Vol 18 (1) ◽  
pp. 39-46
Author(s):  
M. Shuaibu ◽  
A.S. Abubakar ◽  
A.F. Shehu
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Electricity Market ◽  
Energy Demand ◽  
Reactive Power ◽  
Short Circuit ◽  
Renewable Energy Sources ◽  
Dynamic Performance ◽  
Energy Sources ◽  
Fault Ride Through

Renewable energy sources (RES) are being integrated to electrical grid to complement the conventional sources to meet up with global electrical energy demand. Among other RES, Wind Energy Conversion Systems (WECS) with Doubly Fed Induction Generator (DFIG) have gained global electricity market competitiveness because of the flexible regulation of active and reactive power, higher power quality, variable speed operation, four quadrant converter operation and better dynamic performance. Grid connected DFIG-based WECS are prone to disturbances in the network because of direct connection of stator windings to grid. The ability of the Wind Turbine (WT) to remain connected during grid faults is termed the Fault Ride-Through (FRT) capability. The grid code requirement for integrating the DFIG-based WTs to power networks specified that they must remain connected and support the grid stability during grid disturbances of up to 1500 ms. The use of compensation devices offers the best FRT compliance thereby protecting the DFIG and the converters from voltage fluctuations and over currents during the grid fault. The paper presents a review of techniques employed in ensuring FRT compliance. The article also proposes the state-of-the-art techniques for compensating voltage sag/swell and limiting the fault short-circuit current. Keywords: Renewable energy sources, DFIG, wind turbine system, fault ride-through, grid codes, dual-functional DVR

scholarly journals Dynamic Modeling and Performance Analysis of PMSG- based Variable Speed WTG: Case Study of Adama Wind Farm I, Ethiopia

2021 ◽  
Vol 12 (2) ◽  
pp. 155-172
Author(s):  
Zenachew Muluneh ◽  
Gebremichael Teame
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Power Flow ◽  
Wind Farm ◽  
Reactive Power ◽  
Maximum Energy ◽  
Current Control ◽  
Speed Ratio ◽  
Variable Speed ◽  
Grid Side

In this paper, the performance of Permanent Magnet Synchronous Generator (PMSG) -based Variable Speed Wind Turbine Generator (WTG) at Adama Wind Farm I (WTG), connected to a grid is studied. To study the performance of the WTG, both machine and grid side converters are modeled and analyzed very well. On the machine side, maximum power point tracking (MPPT) for maximum energy extraction is done using the direct speed control (DSC) technique, which is linked with the optimal tip speed ratio for each wind speed value considered. On the grid side, dc-link voltage and reactive power flow to the grid are controlled. For this purpose, first, the simulation model of the system is prepared in MATLAB Simulink considering the dynamic mathematical model of the PMSG, and Wind Turbine Aerodynamic model using the user-defined function blocks. Then, the PI regulators designed for direct speed, torque (current) control, and dc-link voltage are employed in the model. Moreover, to study and analyze the behavior of the system in a variable speed operation, a wind speed starting from cut-in wind speed (3m/s) to the rated wind speed (11m/s) is applied in 4s. The simulation result of the existing system model shows that the actual values of performance variables correspond well with the analytical values of the system. In addition, the chosen control algorithms applied in the control system of the generator-side converter are hence verified.

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.

scholarly journals Load Flow Analysis in Hybrid AC-DC Transmission Network

2021 ◽  
pp. 617-624
Author(s):  
Ajith M ◽  
Dr. R. Rajeswari
Keyword(s):  
Power Systems ◽  
Power System ◽  
Transmission Lines ◽  
Power Flow ◽  
Reactive Power ◽  
Short Circuit ◽  
Flow Analysis ◽  
Load Flow ◽  
System Stability ◽  
And Control

Power-flow studies are of great significance in planning and designing the future expansion of power systems as well as in determining the best operation of existing systems. Technologies such as renewables and power electronics are aiding in power conversion and control, thus making the power system massive, complex, and dynamic. HVDC is being preferred due to limitations in HVAC such as reactive power loss, stability, current carrying capacity, operation and control. The HVDC system is being used for bulk power transmission over long distances with minimum losses using overhead transmission lines or submarine cable crossings. Recent years have witnessed an unprecedented growth in the number of the HVDC projects. Due to the vast size and inaccessibility of transmission systems, real time testing can prove to be difficult. Thus analyzing power system stability through computer modeling and simulation proves to be a viable solution in this case. The motivation of this project is to construct and analyze the load flow and short circuit behavior in an IEEE 14 bus power system with DC link using MATLAB software. This involves determining the parameters for converter transformer, rectifier, inverter and DC cable for modelling the DC link. The line chosen for incorporation of DC link is a weak bus. This project gives the results of load flow and along with comparison of reactive power flow, system losses, voltage in an AC and an AC-DC system.

scholarly journals A Three-Phase Bidirectional Grid-Connected AC/DC Converter for V2G Applications

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jingang Han ◽  
Xiong Zhou ◽  
Song Lu ◽  
Pinxuan Zhao
Keyword(s):  
Electric Vehicles ◽  
Control Strategy ◽  
Power Flow ◽  
Reactive Power ◽  
Vehicle To Grid ◽  
Experiment Platform ◽  
Three Phase ◽  
Simulation And Experiment ◽  
Bidirectional Power Flow ◽  
The Mathematical Model

The smart grid and electric vehicles (EVs) are widely used all over the world. As the key role, the Vehicle-to-Grid (V2G) has been attracting increasing attention. The bidirectional grid-connected AC/DC converter is one of the indispensable parts in the V2G system, which can realize bidirectional power flow and meet the power quality requirements for grid. A three-phase bidirectional grid-connected AC/DC converter is presented in this paper for V2G systems. It can be used to achieve the bidirectional power flow between EVs and grid, supply reactive power compensation, and smooth the power grid fluctuation. Firstly, the configuration of V2G systems is introduced, and the mathematical model of the AC/DC converter is built. Then, for bidirectional AC/DC converters, the grid voltage feedforward decoupling scheme is applied, and the analysis of PI control strategy is proposed and the controller is designed. The system simulation model is established based on MATLAB/Simulink, and the experiment platform of the bidirectional grid-connected converter for V2G is designed in lab. The simulation and experiment results are shown, and the results evaluate the effectiveness of the model and the performance of the applied control strategy.

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