Electrical power is the most widely used source of energy for our homes, work places and industries. Population and industrial growth have led to significant increases in power consumption over the past three decades. Natural resources like coal, petroleum and gas that have driven our power plants,industries and vehicles for many decades are becoming depleted at a very fast rate. This serious issue has motivated nations across the world to think about alternative forms of energy which utilize inexhaustible natural resources. Renewable energy like solar, wind, and tidal currents of oceans is sustainable, inexhaustible and environmentally friendly clean energy. Due to all these factors, wind power generation has attracted great interest in recent years. Undoubtedly, wind power is today’s most rapidly growing renewable energy source. Many of the new, large turbines being produced are variable speed turbines,which use doubly fed induction generators (DFIG). These are induction generators which have their stator and rotor independently excited. Turbines of this type are becoming increasingly popular, because the converters required to control them are cheap and subject to less losses.
Due to random variations of wind speed, output power of a wind turbine generator fluctuates continuously. The power and voltage quality of a wind power system consisting of Induction Generator (IG) based wind turbine (IGWT), IGWT with voltage control device and Doubly Fed Induction Generator (DFIG) based wind turbine (DFIGWT) are presented in this work. Blade pitch angle control to limit the output power at turbine’s nominal power is also presented. It is reported that the DFIG-based wind turbine system can smooth the output power and also maintain the terminal voltage at a desired level, as DFIG with two back-to-back voltage source converters that use IGBTs and a capacitor acts as the DC voltage source has real and reactive power control abilities. The comparative results show that DFIGWT-based wind farm (DFIG_WF) has the best response, IGWT-based wind farm (IGWF) with voltage control device has better and IGWF has the worst response. Results indicate that the fluctuation of output power at higher rated rotor speed (near turbine’s base wind speed) and terminal voltage are almost nil for DFIG_WF. All the analysis were carried out using SimPowerSystem tool box in MATLAB.
ABSTRACT The demand for electric energy is increasing day by day that has resulted in exploration of more and more alternate energy sources. Among the available alternate energy sources, wind energy, solar energy and fuel cells have drawn considerable attention. Further, all of these alternate energy sources are also of renewable nature. Among the mentioned alternate energy sources, wind power generation systems have been the most cost competitive alternative among all the environmentally clean and safe renewable energy sources in the world. Both fixed-speed squirrel-cage induction generator and variable speed double fed induction generator have been proposed in the literature for wind turbine generation technology. Since the direction and speed of winds may vary from location to location and time to time, the variable speed wind turbine technology offers inherent advantages over the fixed-speed one. The doubly fed induction-generator (DFIG) is used in tandem with the wind turbine to produce electric energy. The DFIG with the help of the two back to back converters: rotor side and grid side converters, is able to deal with wide variation of wind speed.
This book is very useful for the researchers who are working on wind, PV or Wind-PV hybrid power plants. Renewable energy from wind turbine and solar photovoltaic are the most environment-friendly type of energy to use. Because of combined benefits of renewable energy and hybrid system, a considerable interest has emerged in ‘renewable hybrid’ energy systems. This book, therefore, provides the case study of Wind, PV and Wind-PV hybrid system in different environmental conditions. The modeling of the system components and power control scheme is done using MATLAB/SIMULINK.
The integration of wind power into the grid is now increasing at a significant pace which poses new challenges for power system operators which result to revisions of grid code requirements (GCR) in many countries. In these grid codes, fault ride through is of primary concern. The reason for this is that when large amount of wind energy is supplying the grid, they have to continuously supply power during fault to avoid large frequency deviation. There is even bigger challenge of wind power technology which to bear the same responsibilities for contribution to power system management as conventional synchronous generators does. This is a huge challenge, considering that wind power generation differs fundamentally from conventional generation in various ways Large scale connection of wind generation will influence the levels of damping of the power system. Inadequate network damping causes instabilities, the most common of which are shown in the electromechanical modes of oscillations.
Most of the remote rural areas of Ethiopia are not yet electrified. Electrifying these remote areas by extending grid system is difficult and costly. As the current international trend in rural electrification is to utilize renewable energy resources; solar, wind, biomass, and micro hydro power systems can be seen as alternatives. Among these, wind and solar energy systems are thought to be ideal solution for rural electrification due to abundant solar radiation and significant wind distribution availability nearby the rural community in Ethiopia. This book has been written to satisfy the interest of readers on renewable energy technologies and utilization. The primary reason which motivated the author was to provide some initial information to people who are embarking on a career in the renewable energy technologies and utilization in developing countries like Ethiopia. It is this group of people that the present book is targeted at. This book is organized into six chapters. It covers basic concepts of wind and solar energy technologies, their potential resources and utilization in Ethiopia. Besides it provide thorough discussion on design of hybrid power generation system.
In this book, various problems of wind power and energy storage under market environments have been resolved. In deregulated industry, the electricity market was divided into submarkets for different services: (1) Markets for energy services and (2) Markets for frequency control. Accordingly, the economic operation of independent Battery Energy Storage System (BESS), and then combined Battery Wind Generation Systems (BWGS) in a real-time market have been presented. In addition, we have proposed a novel scheme for BES in order to reduce the cost of wind power assuming a frequency control market.
The increasing penetration of renewable energy in the power system grid makes it one of the most important topics in electricity generation, now and into the future. Tidal current energy is one of the most rapidly growing technologies for generating electric energy. Within that frame, tidal current energy is surging to the fore. Forecasting is the first step in dealing with future generations of the tidal current power systems. The doubly-fed induction generator (DFIG) and the direct drive permanent magnet synchronous generator (DDPMSG) are the most commonly used generators associated with tidal current turbines. The aim of the present work is to propose a forecasting technique for tidal current speed and direction and to develop dedicated control strategies for the most commonly used generators, enabling the turbines to act as an active component in the power system.
The grid codes require taking into account the reactive power of the wind farm/park in order to contribute to the network stability, thus operating the wind farm as active compensator device. This book gives a comparative study of stabilizing wind farms using flexible ac transmission systems (FACTS) units like the (Static Synchronous Compensator) STATCOM and the variable speed wind turbines like the Doubly Fed Induction Generators (DFIGs) during wind speed change and grid fault. Both systems can provide reactive power to the wind farms during dynamic and transient conditions. Simulation analyses were carried out in laboratory standard simulation software called power system computer aided design/electromagnetic transient including DC (PSCAD/EMTDC). The simulated results show that the wind farms could be effectively stabilized with both systems. However, the cost is reduced with the DFIGs system because, apart from generating electric power during steady state,it can also provide reactive power through its frequency converters to stabilize the wind farms without the need of an external reactive power compensation units like the STACOM.
The content of the Work is aimed at the topical issue - integration of increasing infeed of wind power into a power system, in particular its impact on the transmission networks and electricity market. In power system development horizons where forward-looking planning tasks are formed, proper instruments that are able to assess those impacts in progressive stages, comprehensive understanding of the impacts on the entire system operation, electricity markets as well as generating and transmission infrastructural requirements are indispensable for proper decisions of policy makers and planners. The main part therefore focuses on methods and elaboration of approaches for bulk wind power production modelling and simulation primarily intended for infrastructural planning purposes, while technical/economic as well as regulatory aspects of the environment are taken into consideration. The research is carried out within the framework of the European Energy Research Alliance (EERA), Joint Research Programme on Smart Grids, Transmission Planning with the main target focusing on R&D of the next generation of smart grid technologies and system development.
This book focuses mainly on the Wind and photo voltaic hybrid power generation system which are connected to the main grid. The information of the wind system bases on the wind site of EL-ZAFARANA in Hurgada in Egypt. This study investigates the main parameters which are used to define the power quality of the distributed energy resources to be suitable for grid connection.
Today a power system interruption is far more serious, work is interrupted, and modern domestic heating plants cease operating, the processing material is damaged, transportation is impaired and normal life of whole communities is disrupted. This greater dependence on a continuous supply of electrical energy has developed with the ability to build a high degree of reliability into the system. System disturbances caused by the load fluctuations result in changes to the desired frequency value. Automatic Generation Control (AGC), is very important issue in power system operation and control for supplying sufficient and both good quality and reliable electric power. This work deals with the AGC of Electrical (single and multi-area) power systems by using fuzzy logic controller (FLC). Three intelligent AGC controllers have been developed to regulate the power output and system frequency by controlling the speed of the generator with the help of fuel rack position control. The first one is fuzzy based gain scheduler (FGS), the second one is Fuzzy based proportional integral controller (FPIC), and last one is Fuzzy frequency controller (FFC).
The wind power is a popular form of energy generation, the construction of wind farms and small wind electric generators are not universally welcomed because of the power quality issues due to which the converted energy could not be used more effectively. The frequency mismatch is one of the major crisis under the power quality issues when the renewable energy system is connected to the grid. Therefore the main objective of this project is to equalize the number of cycles per second in the grid as well as number of cycles per second in the inverter under different load conditions at various time periods. Hence the proposed project regarding frequency control scheme using grid integrated inverter for wind mill applications effectively compromises the drawbacks. Mainly the frequencies mismatch in the existing systems by equalizing the frequencies difference between the grid as well as the inverter.
The research reported in this book is part of a project to develop a remote wireless sensing network for monitoring the health of highway bridges. Remote health monitoring that does not require direct human observation has many advantages in terms of cost and increased productivity. However, bridges that cannot be easily connected to the power grid require alternative means of acquiring power. This book describes the design of a wind energy harvester to power a particular component in the sensor network, the wireless router. The work discussed in this book provides a review of relevant literature and development of a detailed analytical modeling of wind turbine behavior. The analytical model provides key information on sizing generators and choosing appropriate wind turbine dimensions to provide the required amount of power. The analytical model also distinguishes the performance of vertical and horizontal axis wind turbines. The model is verified through design and testing of a first generation prototype and benchmarking of a commercially available turbine. Based on these results, the design of the next generation wind harvesting system is described.
Hybrid systems are multi source systems that produce electricity independently of the main network(Island-mode). Hybrid systems have been receiving great interest due to tremendous application potential in remote areas, whereby power provision is challenging in terms of transmission and abundance. Hybrid systems make use of photovoltaic panels, fuel cells, and wind turbine to generate electricity from renewable energy resources. This book focuses on controlling active and reactive power in a hybrid systems. In the proposed hybrid, electricity is produced by two renewable energy devices, namely, PV panel and wind turbine. Storage battery plays an integral role in system back up and storing excess energy harvested from natural resources and using of diesel as supported. Matlab software are chosen for hybrid power system simulation.