Induction Generator Wind Farm Research Articles

Robust active disturbance rejection controller design to improve low‐voltage ride‐through capability of doubly fed induction generator wind farms

This study presents the design of a robust active disturbance rejection (ADR) controller in order to improve low-voltage ride-through (LVRT) capability of wind farms connected with doubly fed induction generator (DFIG). The ADR controller is particularly effective in real-time estimation and mitigation of the total effect of various uncertainties against a wide range of parameter variations, model uncertainties and large disturbances. The performance evaluation of the designed controller is performed on an IEEE system under different test cases. The simulation results show that the proposed controller is robust against uncertainties in operating conditions and successfully improves the damping and voltage stability and thus the LVRT capability of DFIGs.

Power Quality Improvement Using Custom Power Devices in Squirrel Cage Induction Generator Wind Farm to Weak-Grid Connection by using neuro-fuzzy control

<p>Wind farm is connected to the grid directly.The wind is not constant voltage fluctuations occur at point of common coupling (PCC) and WF terminal . To over come this problem a new compensation strategy is used . By using Custom power devices (UPQC).It injects reactive power at PCC . The advantages of UPQC is it consists of both DVR and D-STATCOM . DVR is connected in series to the line and it injects in phase voltage into the line .D-STATCOM is connected shunt to the line .The internal control strategy is based on management of active and reactive power in series and shunt converters of UPQC . The power exchainge is done by using DC-link</p>

Transient stability of power system integrated with doubly fed induction generator wind farms

A new quantitative assessment of transient stability for power systems integrated with doubly fed induction generator (DFIG) wind farms is proposed by evaluating the transient energy margin (TEM) through the formulation of the transient energy function (TEF) for multimachine systems. To achieve an accurate TEM, the TEF is modified to account for the separation of the critical machines from the system and an unstable equilibrium point is calculated on the basis of post-fault trajectory reaching the potential energy boundary surface. Simulation results show that such power systems integrated with DFIG wind farms are more sensitive to transient events of higher voltage sag, longer fault clearing time, lower load operation and higher wind power penetration level. It is also observed that machines located far from the fault are also exposed to inferior transient stability because of fault with geographical dispersion of wind farms. As a result, advanced switchgear, faster isolators, more efficient power reserve systems and advanced reactive power compensating devices must be equipped to ensure reliable operation of power systems integrated with the DFIG wind farms during transient events.

Toward Wide-Area Oscillation Control Through Doubly-Fed Induction Generator Wind Farms

Several studies have recently reported the capability of doubly-fed induction generator (DFIG) wind farms in improving the dynamic performance of power systems. Since wind farms are more often located far from the system conventional generation centers, local signals do not comprise enough content for damping inter-area oscillations. This paper presents a particle swarm optimization (PSO)-based wide-area damping controller (WADC) for the DFIG wind farms. The proposed controller is designed with a centralized nature on the basis of latest technological development of wide-area measurement system (WAMS). Damping both inter-area and local oscillatory modes are intended in the design process. The most challenging deficiency against WAMS real-time applications is the variable communication latency which can deteriorate the system stability if not properly accounted for in the controller design process. The proposed WADC hence incorporates effective means to compensate for the destructive characteristics of WAMS delayed signals. The PSO technique is applied to normalize and optimize the parameters of WADC. A set of comprehensive case studies are conducted on a 16-bus six-machine test system and the obtained numerical evidences are thoroughly discussed.

Improvement of Stable Operation Ability for Large-Scale Wind Power System Based on VSC-HVDC Technology

Rigorous transmission technology is important when large-scale wind farm is connected to the power grid. Hence, a power transmission topological framework based on VSC-HVDC is proposed. The mathematical model is built in the dq synchronous frame, and the related direct current control strategy of VSC converters are designed. The doubly fed induction generator wind farm with VSC-HVDC system are modelled in DIgSILENT/PowerFactory. Ultimately, the conditions of the short-circuit fault at the receiving-end VSC AC bus is simulated. The control scheme is proved to be effective.

Equivalence of Large Scale Wind Farm Based on Per-Unit System on RTDS

The paper introduces per-unit system for single Doubly-fed induction generator (DFIG) and large scale wind farm (LSWF) equivalence, based on which their modeling, including main circuit, linkage equation, power equation and rotor motion equation, are built, and equivalence method of LSWF are present. The single DFIG wind farm system and LSWF are built respectively on Real time digital simulator (RTDS). Comparing simulating results of single DFIG with those of LSWF, conclusion shows per-unit value system is correct, equivalent method is feasible.

Design of backstepping power control for grid‐side converter of voltage source converter‐based high‐voltage dc wind power generation system

This study presents a backstepping power control (BPC) design for the grid-side voltage source converter (GSVSC) in a voltage source converter-based high-voltage dc (VSC-HVDC) wind power generation system. First, a dynamic model by taking parameter variations and external disturbances into account is derived on the basis of the space-vector theory to achieve the decoupling control characteristic of the GSVSC in the VSC-HVDC. Moreover, based on the backstepping design procedure, a BPC scheme is developed in the sense of Lyapunov stability theorem for the GSVSC to satisfy multiple objectives of a stable HVDC bus and the grid connection with a unity power factor. The salient feature of the proposed BPC is the introduction of additional error terms into the control laws to reduce the chattering phenomena in traditional backstepping control. In addition, the effectiveness of the proposed BPC scheme is demonstrated by numerical simulations on a doubly-fed induction generator wind farm with VSC-HVDC grid connection, and its advantage is indicated in comparison with a traditional proportional-integral control strategy under a wide range of operating conditions and the possible occurrence of uncertainties.

Voltage sag ride through using Improved Adaptive Internal Model Controller for doubly fed induction generator wind farms

This paper presents the effect of a single pulse dither signal injection in adaptive internal model controller for a doubly fed induction generator (DFIG)-based wind farm. Rotor current controller using adaptive internal model controller is designed with different Adjustment Mechanisms like Lyapunov theory, fuzzy and ANFIS to improve the voltage sag ride through. During voltage sag period the dither signal is injected in the controller to improve the performance of the controller. Simulation results are presented to demonstrate the proposed control strategy during variations in fixed and variable gain Adjustment Mechanism.

Direct model reference adaptive internal model controller for better voltage sag ride through in doubly fed induction generator wind farms

This paper presents the function of a direct model reference adaptive internal model controller (DMRAIMC) with variable gain adjustment mechanism for a doubly fed induction generator (DFIG) in a wind farm. Rotor current is controlled using the above controller with variable gain adjustment mechanism achieved using fuzzy sets and ANFIS to improve the voltage sag ride. Performance of the variable gain and linearly variable gain adjustment mechanisms are compared and their improvements are explored. Simulation results are used to demonstrate the effectiveness and robustness of the proposed control strategy, during variations in the variable gain adjustment mechanism.

Mitigating SSR Using DFIG-Based Wind Generation

Subsynchronous resonance (SSR) phenomenon in wind farms connected with series compensated transmission network has been researched in recent literature. Mitigating SSR using FACTS devices such as TCSC, SVC, and STATCOM has also been explored in the literature. The ability of the power converters in doubly-fed induction generator (DFIG) wind farms in mitigating SSR has rarely been investigated. In this paper, the DFIG converters will be explored for SSR mitigation. The investigation in this paper includes the design of auxiliary SSR damping controller and selection of control signals. Residue-based analysis, root locus diagrams, and time-domain simulation in Matlab/Simulink will be carried out. The major contributions of the paper are 1) investigation of the potential of wind farm converters for SSR mitigation and 2) identification of an effective control signal for SSR damping controller to simultaneously enhance both subsynchronous and supersynchronous resonance modes.

Novel Coordinated Converter Control (3C) Strategy for Enhancement of Fault Ride-through Capability of Doubly Fed Induction Generator Wind Farms

A novel coordinated converter control strategy is proposed in this article for enhancement of the fault ride-through capability of doubly fed induction generator based wind farms. The proposed coordinated converter control strategy is activated only during the instance of fault clearance in order to achieve rapid restoration of terminal voltage and thereby enhance the post-fault performance capability of wind generators connected to the distribution network. An extensive simulation study is carried out employing PSCAD/EMTDC software (Manitoba, Canada). The simulation results demonstrate the laudable performance of the doubly fed induction generator achieved by employing the coordinated converter control strategy.

Validation of a double fed induction generator wind turbine model and wind farm verification following the Spanish grid code

ABSTRACTWind turbine manufacturers are required by transmission system operators for fault ride‐through capability as the penetration of wind energy in the electrical systems grows. For this reason, testing and modeling of wind turbines and wind farms are required by the national grid codes to verify the fulfillment of this capability.Therefore, wind turbine models are required to simulate the evolution of voltage, current, reactive and active power during faults. The simulation results obtained from these wind turbine models are used for verification, validation and certification against the real wind turbines measurement results, although evolution of electrical variables during the fault and its clearance is not easy to fulfill.The purpose of this paper is to show the different stages involved in the fulfillment of the procedure of operation for fault ride‐through capability of the Spanish national grid code (PO 12.3) and the ‘procedure for verification, validation and certification of the requirements of the PO 12.3 on the response of wind farms in the event of voltage dips’. The process has been applied to a wind farm composed of Gamesa G52 wind turbines, and the results obtained are presented. Copyright © 2011 John Wiley & Sons, Ltd.

Modeling, Analysis, and Control for the Rectifier of Hybrid HVdc Systems for DFIG-Based Wind Farms

In order to improve the dynamic performance of the hybrid HVdc system for doubly fed induction generator wind farms, this paper presents the modeling, analysis, and control methods for its line-commutated rectifier. First, the state variable model of the rectifier subsystem on the reference frame is derived considering different control modes of the current source inverter subsystem. Then, the ac current dynamic of the rectifier subsystem is quantitatively analyzed based on the eigenvalue analysis method. According to the analysis results, a double loop control scheme is designed: the inner loop utilizes the inverse system control technique plus a switchable phase-lead compensator, and the outer loop implements an ordinary propotional-integral controller. Finally, the validity of the quantitative analysis method and the superiority of the proposed control scheme are verified by Simulink/SimPowerSystems simulations.

Stability improvement of fixed speed induction generator wind farm using STATCOM during different fault locations and durations

This paper investigates the impact of the fault ride through on the stability of fixed speed wind farm interconnected grid. The effect of fault location and its duration time are studied for different fault types. The contribution of Static Synchronous Compensator STATCOM to support the fixed-speed wind farm interconnected electric grid during different fault locations and different fault duration times are investigated. Simulation test cases using MATLAB-Simulink are implemented on a 9 MW wind farm exports a power to 120 KV grid. The simulation results show the influence of fault location and its duration on active power, reactive power, and bus voltage of the wind farm.

Model Parameters Identification Method for Wind Farms Based on Wide-Area Trajectory Sensitivities

Numerical simulation, which relies on precise mathematical models and parameters of elements, is currently the most efficient tool to study the power system stability. However, since some of grid companies in China did not foresee the rapid development of wind power, the lack of parameters information of wind farms negatively affects the system simulation study with scalable wind energy integration. In addition, the field condition of wind farm also limits the grid company to equip extra real-time measurement equipments to measure the dynamic response of wind generators. This paper proposes a method based on wide-area trajectory sensitivities to identify the parameters of FSIG-based (Fixed Speed Induction Generator) wind farms. By this method, the data recorded by Wide Area Measurement System (WAMS) are used to process identification, which satisfies the requirement from grid companies. This paper gives a detailed description on the modelling of identification, the analysis of trajectory sensitivity and the algorithm to solve the optimization problem. Both of the case studies of modified 9 and 39 bus systems show the numerical simulation results are closer to realistic after parameter identification, and it is feasible and beneficial to use this identification method based on WATS to enhance the accuracy of system simulation with scalable wind energy integration.