Induction Generator Based Wind Farm Research Articles

Stabilization analysis for nonlinear interconnected system with memory based coupled sampled data control via quantum-inspired genetic algorithm

In the realm of modern interconnected systems, achieving stability represents a pivotal challenge due to the complex dynamics among various components. This paper presents a new approach to stability analysis, leveraging linear matrix inequalities and Lyapunov-Krasovskii functionals. The framework of memory-based coupling sampled data control is enhanced by a quantum genetic algorithm. By incorporating linear matrix inequality approach, this study establishes a robust mathematical foundation for characterizing stability conditions and synthesizing control gains. This innovative integration provides a powerful toolset to optimize control parameters while mitigating the impact of disturbances. The simulation findings are explicitly based on experimental values of two-area interconnected power systems with doubly fed induction generator based wind farm, which guarantees the asymptotic stability of the proposed controller.

Subsynchronous oscillation and its mitigation of VSC-MTDC with doubly-fed induction generator-based wind farm integration

Subsynchronous oscillation and its mitigation of VSC-MTDC with doubly-fed induction generator-based wind farm integration

A Review of Intelligent Control Systems for Grid Tie Doubly Fed Induction Generator Based Wind Farm

A Review of Intelligent Control Systems for Grid Tie Doubly Fed Induction Generator Based Wind Farm

A split Bregman method solving optimal reactive power dispatch for a doubly-fed induction generator-based wind farm

This paper proposes an optimal reactive power control method to maximize wind farm revenue and minimize the total electrical losses of a doubly-fed induction generator (DFIG)-based wind farm. Specifically, the split Bregman method is used to solve the optimal control problem in a distributed manner. That is, the optimization problem is decomposed into sub-problems by the optimal distributed control strategy, and each sub-problem is solved independently in each local controller through the parallel method, which reduces the calculating burden and improves the information privacy. Thus, when a fault occurs, the proposed distributed control strategy can overcome the system fault and improve the reliability and security of the system. Furthermore, an economic financial model of annual revenue is contributed to examine the income impact with or without certified emission reduction (CER) by the clean development mechanism (CDM). Compared with the dual ascent (DA) method, sequential quadratic programming (SQP) method and the proportional dispatch method (PDM), the annual revenue (AR) of the wind farm using the proposed split Bregman method is the highest. Simulation results demonstrate that this method has promising performance in both optimization quality and computational efficiency.

Investigation on the Electrothermal Performance of a High-Temperature Superconducting Cable in an Offshore Wind Farm Integrated Power System: Fault and Islanding Conditions

The main contribution of this article is to study the electrothermal performance of a 22.9 kV high-temperature superconducting (HTS) AC cable under transients, such as short-circuit faults and islanding operating mode (IOM) of a wind farm. For this purpose, an HTS cable connects a 12 MVA doubly fed induction generator-based wind farm to the load center under two different scenarios of the grid. In the first scenario, the upstream grid is located far from the load center and most of the demanded load is supplied by the wind farm, while in the second scenario, a part of the load is supplied by the wind farm and the rest is supplied by the upstream grid located near the load center. In case of faults and transients in the upstream grid, protection systems isolate the wind farm, and thus, it operates in a specific mode, called IOM. Results indicated that the location of faults and transients, especially IOMs, plays a significant role in the electrothermal performance of HTS cable.

Design of Capacitive Bridge Fault Current Limiter for Low-Voltage Ride-Through Capacity Enrichment of Doubly Fed Induction Generator-Based Wind Farm

The increase in penetration of wind farms operating with doubly fed induction generators (DFIG) results in stability issues such as voltage dips and high short circuit currents in the case of faults. To overcome these issues, and to achieve reliable and sustainable power from an uncertain wind source, fault current limiters (FCL) are incorporated. This work focuses on limiting the short circuit current level and fulfilling the reactive power compensation of a DFIG wind farm using a capacitive bridge fault current limiter (CBFCL). To deliver sustainable wind power to the grid, a fuzzy-based CBFCL is designed for generating optimal reactive power to suppress the instantaneous voltage drop during the fault and in the recovery state. The performance of the proposed fuzzy-based CBFCL is presented under a fault condition to account for real-time conditions. The results show that the proposed fuzzy-based CBFCL offers a more effective solution for overcoming the low voltage ride through (LVRT) problem than a traditional controller.

Complete Provision of MPC-Based LFC By Electric Vehicles With Inertial and Droop Support from DFIG-Based Wind Farm

This paper taps on the participation ability of the Electric Vehicles Aggregator (EVA) in Load Frequency Control (LFC). The focus here is on EVA complete provision of LFC using Vehicle-to-Grid technology. This provision is possible however it faces two main challenges. The first one is the post-disturbance oscillations in the frequency when there is a time delay in the system. To cope with these oscillations two approaches are suggested. One is the application of constraints in the designing of model predictive control for LFC. Whereas the other is the emulated inertial and droop support from doubly-fed induction generator-based wind farm. This support along with the oscillation damping improved the overall frequency response to a disturbance. The second challenge is the variation in the sources’ especially of the EVAs’ capacity used for LFC. Acquiring the dynamic participation factor for these sources, successfully accommodated the variation in their capacities. Finally, this novel idea is tested through various case studies in Matlab/Simulink, including single and multiple LFC events, in the isolated and three-area systems. Hence establishing the EVs and DFIG-WFs’ potential of participating in grid frequency control by replacing partly or fully the fossil fuel-based sources.

Improving Transient Stability of Dual Stator-Winding Induction Generator-Based Wind Farms by Slip Frequency Control

This article studies improving rotor-speed stability of dual stator-windings induction generators (DWIG)-based wind turbines during a severe fault in the power system. A novel instantaneous slip frequency control (ISFC) with a supplementary control loop containing braking resistors (BRs) is introduced. The ISFC drive technique is selected primarily for its fast-dynamic performance. An active power feed-forward loop in this drive technique can adequately regulate the generator’s slip restricting reactive power consumption. The supplementary control loop includes a mechanism that can bring sufficient braking resistance into the circuit to keep the slip’s optimal value according to the wind speed. At first, the proposed DWIG-based wind turbine equipped with the ISFC drive technique is described. Then the factors affecting the rotor speed stability are analyzed, and the improved ISFC is proposed. The topology and the proposed drive technique are simulated in MATLAB/Simulink platform and experimented with a scaled 1.2-kW prototype. Both simulation and experimental results demonstrate the significant impact of the proposed method.

Enhanced modelling of doubly fed induction generator in load flow analysis of distribution systems

This paper presents an accurate framework for incorporating the doubly fed induction generator based wind farms in load flow analysis of distribution systems. The proposed model for doubly fed induction generator is based on an accurate equivalent circuit and also takes into consideration the voltage dependent reactive power limits associated with the doubly fed induction generator. In addition, the developed approach is capable of handling a doubly fed induction generator operating in either maximum power point tracking or non-maximum power point tracking modes. The proposed PQ model of doubly fed induction generator easily fits into the forward–backward technique that is typically employed for obtaining the load flow solution of distribution networks. Test results on 19-bus and 133-bus systems are reported to indicate the effectiveness of the proposed approach.

A Recent Analytical Approach for Analysis of Sub-Synchronous Resonance in Doubly-Fed Induction Generator-Based Wind Farm

Sub-synchronous resonance (SSR) phenomenon occurs due to the interaction between wind turbine generators and series-compensated transmission lines. A doubly-fed induction generator (DFIG) is considered one of the most widely implemented generators in wind energy conversion systems. SSR analysis based on the eigenvalue method is the most important among the used methods. The accuracy of the eigenvalue method depends on the initial values of state variables. Previously, the initial values of the state variables were calculated based on the iterative approach which is suffering from convergence problem, lacking accuracy, and requiring a long computation time. Moreover, many steps and details haven’t been provided. Consequently, it is urgent to fill this gap and show how can implement the SSR analysis model in detail. In this paper, a new application of a recent analytical approach is proposed for SSR analysis. All information is provided, and the SSR analysis model of a DFIG-based series compensated wind farm is built step-by-step. In order to prove the effectiveness and accuracy of the proposed method, the eigenvalue analysis based on the proposed and iterative methods is compared with the time-domain simulation results at different wind speeds and variable compensation levels. The results prove that the eigenvalue analysis based on the proposed method is more precise, where it is consistent with the simulation results in all studied cases. MATLAB software is used to validate the results.

Robust finite-time controller for damping of subsynchronous resonance in doubly fed induction generator wind farm

To alleviate subsynchronous resonance in doubly fed induction generator–based wind farm, this study devises a robust nonlinear control for a rotor-side converter based on a fractional-order sliding mode controller. The designed fractional-order sliding mode controller is able to realize finite-time control and reduce the control time compared with terminal sliding mode control, which contributes to the faster mitigation of subsynchronous resonance. Impedance-based analysis and transient simulation are carried out to evaluate the performance of the fractional-order sliding mode controller compared with terminal sliding mode control and subsynchronous damping control. Simulation results verify that the fractional-order sliding mode controller is able to damp SSR within shorter time and effectively reduce the fluctuation range of a system’s transient responses under various working conditions of compensation degrees and wind speeds. Furthermore, the fractional-order sliding mode controller enhances the robustness under external disturbance and parametric uncertainty, ensuring safe operation of the practical wind farm.

Optimized control of Coordinated Series Resistive Limiter and SMES for improving LVRT using TVC in DFIG-base wind farm

Maintaining connectivity to the grid and resisting against voltage dip in the grid are important for doubly fed induction generator based wind farms (DFIG-based WFs) to meet the requirements of new grid codes. In this paper, a hybrid approach is proposed to improve low voltage ride through (LVRT) capability in DFIG-based WF using an improved series resistive limiter (SRL) in rotor and superconducting magnetic energy storage (SMES) as an improved chopper circuit (ICC) along with the transient voltage control (TVC) method. The connection of the wind turbine to the grid while preventing the disturbances duo to the voltage dip (VD) through compensating the VD by using the proposed controller and ICC method. The new control method relies on active power control and reactive power injection to the grid for improving the performance of DFIG-based WF during the grid VD. The proposed controller and ICC method reduce the VD at the point of common coupling (PCC) while improving the overall system performance by injecting active and reactive power into the grid during a fault. In addition, the proposed methods effectively improves the LVRT capability of the generator and maintains its controllability during a fault Compared to other solutions including the crowbar parallel resistance. The proposed methods are simpler, cheaper, and have less computational complexity compared to active methods including series voltage compensator of the stator along with power electronic converters (PEC). Finally, the continuous operation of a 9 MW wind turbine during a VD in the grid has been investigated and simulated using the proposed method in Matlab/Simulink®.

A Subsynchronous Oscillation Suppression Method Based on Self-Adaptive Auto Disturbance Rejection Proportional Integral Control of Voltage Source Converter Based Multi-Terminal Direct Current System with Doubly-Fed Induction Generator-Based Wind Farm Access

A subsynchronous oscillation suppression strategy based on self-adaptive auto disturbance rejection proportional integral controller is proposed for doublyfed induction generator-based wind farm integrated into grid through voltage source converter based multi-terminal direct current. In this strategy, the nonlinear PI controller is constructed by fal function to replace the traditional linear PI controller, and then the tracking differentiator is used to arrange the appropriate transition process in combination with the idea of active disturbance rejection control, and the self-adaptive auto disturbance rejection proportional integral controller is designed. By applying the controller to the inner loop of the converter on the rotor side of the doubly-fed induction generator, the adaptability of the control parameters of the inner loop to the change of operating conditions of the system can be improved, and the dynamic performance of the system can be improved. The simulation results on PSCAD/EMTDC show that, compared with SSDC, when the wind speed is 7.5 m/s, 8.5 m/s and 9.5 m/s, the convergence time can be shortened by 0.2 s, 0.1 s and 0.25 s, respectively. When the number of grid-connected doubly-fed induction generator wind turbines is 200 and 220, the convergence time is shortened by 0.1s. When the self-adaptive auto disturbance rejection proportional integral controller and the multi-channel variable-parameter additional subsynchronous damping controller work together, the convergence time under the above three wind speeds are 2.7 s, 2.7 s and 2.3 s, respectively. When the number of grid-connected doubly-fed induction generator wind turbines is 200 and 220, the convergence time is 2.65 s and 2.75 s, respectively. It can be concluded that the self-adaptive auto disturbance rejection proportional integral controller can realize the effective suppression of the subsynchronous oscillation under different operating conditions of the wind farm via the comparison with the additional subsynchronous damping control of doubly-fed induction generator. Besides, subsynchronous oscillation will converge faster and the stability of the system can be enhanced when the self-adaptive auto disturbance rejection proportional integral controller and the multi-channel variable-parameter additional subsynchronous damping controller work together.

Effects of Fault Current Limiters in Transient Stability Performance of Hybrid Wind Farm

Low voltage ride through capability is an ability of the wind farm to stay connected with grid at the time of disturbance in the power system. The penetration of wind based renewable energy resources is increasing and the low voltage ride through consideration is vital for systems studies. The literature available demonstrates the improvement in low voltage ride through either by using fault current limiters or by implementing a control strategy for induction generator based wind farms. In this paper the low voltage ride through capability enhancement of the fixed speed induction generator is presented with various fault current limiters. The authors have presented the effects of fault current limiters in the aggregated hybrid wind farm consisting the combination of fixed speed induction generators and doubly fed induction generators which is not available in literature so far. A transient fault is simulated using PSCAD/EMTDC software in both the cases and the results are presented and discussed.

Overcurrent protection scheme for collector lines in wind farm based on fault component current correlation analysis and multi‐agent system

Collector line relay failures of large-scale grid-connected wind farms have not received much attention so far. In this study, the adaptability of conventional overcurrent setting method is analysed when used in doubly fed induction generator-based wind farms, revealing the coordination difficulties between collector line relay and fuse protection of wind turbine (WT) branch as well as the potential maloperation causes of backup overcurrent relays (BOCRs). Then, a novel three-stage setting method of overcurrent relays is proposed. In view of time-bound instantaneous overcurrent relays, a time delay setting approach is put forward considering the time–current characteristic of fuses. Based on the multi-agent system, which is both flexible and effective, comprehensive criteria containing fault component current correlation analysis and differential current criterion are applied to BOCRs. The proposed scheme is validated by the simulation of 46-WT wind farm on DIgSILENT/Powerfactory platform. Simulation results show that the relay is able to trip within 0.32 s and the BOCRs perform well when confronting single fault or even multiple faults.

Sub-Synchronous Resonance Damping Control for Series-Compensated DFIG-Based Wind Farm With Improved Particle Swarm Optimization Algorithm

In this paper, we propose an improved sub-synchronous resonance (SSR) damping controller (SSRDC) and a related control strategy to mitigate the SSR in a capacitive series-compensated double-fed induction generator based wind farms, based on the damping torque analysis. The proposed strategy is utilized for enhancing the system stability. Compared with the traditional damping controller, the proposed SSRDC is simultaneously embedded into the $d$ -axis and $q$ -axis control channels in the inner current loop of the rotor-side converter. On this basis, combined with the eigenvalue analysis and improved particle swarm optimization algorithm, the optimum gain coefficients of the SSRDC can be determined for maximizing the mitigation effect under different operation conditions of the series compensation levels and wind speeds. Moreover, the effect of the weight coefficients in the objective function on the SSR suppression is also investigated. Finally, the time-domain simulations are carried out to demonstrate the effectiveness of the proposed control strategy for mitigating the SSR and suppressing the connected power system oscillations.

Analysis and mitigation of subsynchronous resonance based on integral control for DFIG‐based wind farm

Series capacitor compensation technology has been widely used in long-distance wind power transmission, which can improve the power transmission capacity and enhance the static stability of the power system. However, adding a series capacitor in the line may present a potential risk of subsynchronous resonance (SSR) to the system. This study focuses on the SSR caused by induction generator effect of the doubly-fed induction generator-based wind farms. The SSR phenomenon of wind power system is researched by the impedance analysis method. A mitigation strategy of adding a virtual inductance based on integral control is proposed for enhancing the system stability and alleviating the SSR. It has clear and intuitive physical concept, which is beneficial to system integration and provides a simpler and more economic method for mitigating SSR. Moreover, the principle and process of controller design are elaborated. Moreover, the time-domain simulation is carried out to prove the effectiveness of the proposed control strategy under different operating conditions considering various compensation levels and wind speeds. Finally, the suppression effects of the virtual inductance in rotor-side converter and grid-side converter are compared.

A New H-IRKA Approach for Model Reduction with Explicit Modal Preservation: Application on Grids with Renewable Penetration

Multi-input multi-output (MIMO) model reduction is essential for applying many modern control design methods in power systems. The challenges of MIMO model order reduction of the modern power grid increases with the inclusion of renewables such as inverter-interfaced wind farms, which introduces complexity in such power system models. The difficulty in reducing such models using gramian-based and modal truncation approaches is demonstrated, whereas a relatively new Interpolatory approach of the Iterative Rational Krylov Algorithm (IRKA) shows promising results. Next, a heuristic-based IRKA is proposed to improve the accuracy of model order reduction of modern grids with explicit preservation of the “critical modes” of the system. Tests on a 16-machine New England–New York system with two doubly-fed induction generator-based wind farms and a larger Brazilian system model demonstrate the effectiveness of the proposed approach.

Sub‐synchronous resonance mitigation by a STATCOM in doubly fed induction generator‐based wind farm connected to a series‐compensated transmission network

With the fast development of wind power generation, large-scale wind farms are connected to an electrical network which is series compensated to increase transmission capacity. However, a series-compensated power system may encounter with a sub-synchronous resonance (SSR) problem. Flexible AC transmission systems controllers are widely applied to mitigate SSR and improve the transient stability of the power system. A static synchronous compensator (STATCOM) with an SSR damping controller is proposed to mitigate the potential of SSR in a series-compensated doubly fed induction generator-based wind farm. The local signal is used as the input of the damping controller, which is feasible to be implemented in a practical project. Taking account of different series compensation levels and operating conditions, extensive transient simulations have been carried out using power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC) to demonstrate the capability of STATCOM in damping SSR. It is shown that the SSR is successfully alleviated by STATCOM, which also verifies the effectiveness of the proposed STATCOM controller in improving the stability of the transmission system.

Coordinated Control Method for DFIG-Based Wind Farm to Provide Primary Frequency Regulation Service

With the rapid growth of wind power penetration, system operators are required to enforce grid codes that implement frequency regulation of wind farms. This paper presents a distributed cooperation framework for a doubly fed induction generator based wind farm to participate in primary frequency regulation, including imitated inertia and droop characteristics similar to conventional plants. Compared with centralized schemes, the control efficiency is significantly improved. To realize fast distributed coordination and optimal power distribution among wind turbines (WTs), a distributed Newton method is developed, which only requires WTs to exchange limited information with their neighbors over a sparse communication network, and has a super-linear convergence rate. By introducing an index of state of energy, this method can adequately exploit the kinetic energy of all WTs without loss of security. The simulation results indicate that the method exhibits satisfying dynamic performance and reliability, and the system frequency can be stabilized faster when the wind farm controlled by the proposed method participates in frequency control.