Offshore Wind Energy Conversion System Connected to the Electric Grid: Modeling and Simulation

This paper is on modeling and simulation for an offshore wind system equipped with a semi-submersible floating platform, a wind turbine, a permanent magnet synchronous generator, a multiple point clamped four level or five level full-power converter, a submarine cable and a second order filter. The drive train is modeled by three mass model considering the resistant stiffness torque, structure and tower in deep water due to the moving surface elevation. The system control uses PWM by space vector modulation associated with sliding mode and proportional integral controllers. The electric energy is injected into the electric grid either by an alternated current link or by a direct current link. The model is intend to be a useful tool for unveil the behavior and performance of the offshore wind system, especially for the multiple point clamped full-power converter, under normal operation or under malfunctions

Supervisory Control of Full Converter Wind Generation Systems to Meet International Grid Codes

This thesis proposes a new supervisory control scheme for full converter wind generators (FCWGs) in compliance with the latest international grid codes. Intermittent behaviour of wind turbines and maximum converter capacity are taken into account in determining the reactive power injection to the grid following severe disturbance. Detailed simulations show that the proposed controller can improve the fault-ride-through capability of FCWGs while also providing support to the network as required by the grid codes

IMPACT OF WIND ENERGY CONVERSION SYSTEMS ON GENERATOR DISTANCE PHASE BACKUP PROTECTION

The need for clean, renewable energy has resulted in new mandates to augment, and in some cases replace conventional, fossil based generation with renewable generation resources. Wind generation is among those resources that have been at the center of attention. These resources are environmentally friendly, renewable, and they do not produce green-house gases. Therefore, there has been a significant growth in the integration of wind power into power systems networks in recent years. This structural change in power systems results, however, in new concerns regarding the reliable and secure operation of the power system with high penetration of wind energy conversion systems. This thesis investigates the impact of large doubly-fed induction generator- and full- frequency converter-based wind farms on the performance of generator distance phase backup protection (Relay (21)) and the generator capability curves. In this context, comprehensive studies are conducted on a sample power system incorporating large DFIG- and FFC-based wind farms tapped to the transmission system. The results of these studies which provide an in-depth assessment of Relay (21) performance in the presence of this type of wind energy conversion systems show that a wind farm tapped to a transmission line has an adverse effect on the distance phase backup protection of a nearby generator. The severity of such an impact varies according to the fault type and its location. Moreover, the adverse effect of the wind farms on Relay (21) performance extends to affect the coordination between generator distance phase backup protection and the generator overexcited capability limits. Such an impact varies also according to the fault type, fault location and generator loading. The time-domain simulation studies are carried out using the ElectroMagnetic Transient Program (EMTP/RV)

Large Grid-Connected Wind Turbines

This book covers the technological progress and developments of a large-scale wind energy conversion system along with its future trends, with each chapter constituting a contribution by a different leader in the wind energy arena. Recent developments in wind energy conversion systems, system optimization, stability augmentation, power smoothing, and many other fascinating topics are included in this book. Chapters are supported through modeling, control, and simulation analysis. This book contains both technical and review articles

Artificial Intelligence-Based Fault Tolerant Control Strategy in Wind Turbine Systems

This is an Open Access article published by ILHAMI COLAK. Content in the UH Research Archive is made available for personal research, educational, and non-commercial purposes only. Unless otherwise stated, all content is protected by copyright, and in the absence of an open license, permissions for further re-use should be sought from the publisher, the author, or other copyright holder.Power converters play an important role as an enabling technology in the electric power industry, especially in Wind Energy Systems (WESs). Where they ensure to regulate the exchanging powers between the system and the grid. Therefore; any fault occurs in any parts of these converters for a limited time without eliminating, it may degrade the system stability and performance. This paper presents a new artificial intelligence-based detection method of open switch faults in power converters connecting doubly-fed induction (DFIG) generator wind turbine systems to the grid. The detection method combines a simple Fault Tolerant Control (FTC) strategy with fuzzy logic and uses rotor current average values to detect the faulty switch in a very short period of time. In addition, following a power switch failure, the FTC strategy activates the redundant leg and restores the operation of the converter. In order to improve the performance of the closed-loop system during transients and faulty conditions, current control is based on a PI (proportional-integral) controller optimized using genetic algorithms. The simulation model was developed in Matlab/Simulink environment and the simulation results demonstrate the effectiveness of the proposed FTC method and closed-loop current control schemePeer reviewe

Loss allocation in a distribution system with distributed generation units

In Denmark, a large part of the electricity is produced by wind turbines and combined heat and power plants (CHPs). Most of them are connected to the network through distribution systems. This paper presents a new algorithm for allocation of the losses in a distribution system with distributed generation. The algorithm is based on a reduced impedance matrix of the network and current injections from loads and production units. With the algorithm, the effect of the covariance between production and consumption can be evaluated. To verify the theoretical results, a model of the distribution system in Brønderslev in Northern Jutland, including measurement data, has been studied