This study investigates the impact of wind power on tourism on Gotland. The main objective is to identify how tourists on Gotland during their holidaying perceive the visual features associated with wind turbines in the landscape. Additionally, it is sought to establish whether tourists plan to return to Gotland despite the presence of wind power installations, with a special focus on first-time tourists. Using a structured questionnaire technique on a sample size of 735 respondents, this study reveals that 8% of tourists perceive wind turbines negatively. Next, the study identifies that the decision to return to Gotland of absolute majority of tourists, including first-time visiting tourists, is not impacted by the presence of wind turbines. Lastly, it has been concluded that a potential on the island exists to develop a form of ‘wind power tourism’.
The primary task of a wind turbine is to generate electricity from the wind and to supply the produced power to the user. Control of a wind turbine is an integral part of the wind power generation system for proficient operation of the wind turbine, to ensure the maximum power production and finally, maximum energy capture from a wind turbine system. In order to avoid problems at installation, it is required to test the power electronics and study the performance of the controller in a laboratory environment. The aim of this book is therefore to propose and validate maximum power point control strategies for wind turbine and most importantly, to develop a prototype of a small wind energy conversion system that emulates the steady state and dynamic behavior in a laboratory environment.
A wireless body area network (WBAN) consists of several mobile devices worn on the human body. WBANs have enormous potential in health monitoring systems as it eliminates the inconvenience of having wires around the patient’s body, offering more freedom of movement and comfort, enhanced monitoring, and the administration of at-home treatment. Low power consumption is crucial for such applications due to the limited capacity of portable batteries. The power consumption of wireless communication is especially important since the radio typically consumes the majority of the energy in such systems. There are two ways to solve this energy constraint. First, we reduce the RF communication power by optimizing the radio for the wireless communication channel. The RF communication channel is measured using custom hardware with UWB and narrowband signals, and it is observed that the channel has periods of time when it is good enough for a low sensitivity, low power receiver to be used. Second, we scavenge the energy from propagating radio waves with a subthreshold CMOS rectifier. Theoretical analysis of a subthreshold CMOS rectifier is presented, and used to maximize the sensitivity.
Pakistan has been experiencing the worst energy/power crisis of its history since 2007. This situation is getting worst on every year passing. It all start with power shortage that slowly turned into deficit in other forms of energy like gas, CNG and other petroleum products when both households and organization / firms resorted to these alternative sources of energy. The severe electricity shortfall compelled the authorities to impose load-shedding schedules of more than eight hours a day. Moreover, in addition to quantification of output losses, the effect on employment, cost of production, delay in supply orders, down fall of income which also effects on their children's education, health related matters of family and other domestic problems.
This study presents a new approach in which a wind tunnel apparatus is used to identify the efficiency of power output by a wind turbine with a 400W rating. Moreover, the study addresses a significant issue concerning the turbulence formed by a natural wind which can be eliminated or reduced with the use of the proposed wind tunnel. Wind power characteristics that indicate power output vs. wind velocity are obtained by performing a number of case studies. The case studies include normal operation of the experimental wind turbine at variable wind velocity values with and without proposed wind tunnel. A certain level of turbulence is formed and the wind turbine power output is measured and recorded for a number of cases. The statistical t-Test and ANOVA analyses showed that the suggested approach could be useful for wind turbine manufacturers to evaluate the degree that contributes to the variability of renewable energy production. Besides, the results may be helpful to support educational institutions in providing renewable energy awareness in the US by providing adequate information for the selection and handling of the parameters that control the variability of the energy needs.
This book presents a set of proposals for advanced control functionalities in order to achieve a coordinated and optimized voltage management of distribution networks comprising several Distributed Generation units, controllable loads, storage devices and microgrids. Large scale integration of Distributed Energy Resources, namely Distributed Generation at the Medium Voltage level and microgeneration at the Low Voltage level, poses several technical challenges for distribution network operation, especially concerning voltage control. Accordingly, the development of specific control solutions is required in order to maximize the integration of these units in the distribution system. The work presented here focused on the development of a conceptual framework model for regional ancillary services markets for voltage control. In addition, a methodology for voltage and reactive power control to be integrated in a tool for managing network operation in the short-term time-horizon is proposed.
In an alternating current system, if the system is resistive i.e. voltage and current are in phase only real power is transmitted and if there is a time shift between voltage and current both active and reactive power are transmitted. When the average with respect to time is calculated, the average active power exists causing a net flow of energy from one point to another, whereas average reactive power is zero, irrespective of the network or state of the system.This project presents and compares three algorithms based on swarm intelligence and evolutionary techniques for solving the reactive power optimization problem Case studies on the IEEE 10-bus,34-bus systems illustrate the effectiveness of these algorithms in terms of the quality of the solutions found and their convergence characteristics. The results proved that the proposed DEPSO algorithm provides higher-quality solution with smaller iterations than the other two methods. DEPSO indeed outperforms DE or basic PSO method on this problem when comparing power loss reduction and number of iterations required for achieving convergence
The fast growth of wind generation has led to concern about the effect of wind power on the transient stability of the electric grid. New studies must be performed in order to evaluate the behaviour of the wind farms after severe faults and improve the design of the wind farms in an efficient and economical way. Under such circumstances, the most demanding requisite for wind farm is the Fault Ride-Through (FRT) capability. Wind farms connected to high voltage transmission system must stay connected when a voltage dip occurs in the grid, otherwise, the sudden disconnection of great amount of wind power may contribute to the voltage dip, with terrible consequences. Therefore, the dynamic and transient analyses of wind generators are necessary. This book proposes some methods with suitable control strategies for wind power application that helps wind farms to be connected during grid disturbances, achieving the grid code provisions in both steady and transient conditions. The results in this book can be significant in understanding the transient stability phenomena of fixed and variable speed wind turbines and also in designing of wind farms based on transient stability requirements.
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.
In the present context of blackouts and severe power shortage it is only explicable that Nepal, among other alternative energy sources, is trying to develop its own wind power. However, lots of factors seem to be impeding its development. Therefore, in order to understand and explore the possible routes to success for the wind power development in Nepal, this book looks into the close neighbor, India and investigates its relative success in Wind Industry. Upon analysis on Indian success on wind technology with regard to the contribution of low carbon technology transfer, it was observed that India effectively assimilated wind technology from abroad following a range of initiatives. Further, exploring the issues related to wind power development in Nepal, illustrated that similar initiatives are required in Nepal as well. Meanwhile, one could also agnize the potential of Nepal-India collaboration in the development process of wind technology in Nepal. This book is thus expected to be useful to wind energy developers and promoters trying to bring wind technology into mainstream in the developing countries and also to low carbon technology transfer advocates.
In the field of electrical power generation, the wind energy is one of the important sources of renewable energy. The main problem with this type of energy is the variable nature of the wind speed. The wound rotor induction generator is used to handle this speed variations by adequate voltage injections in the rotor circuit to maintain the stator voltage and frequency constant irrespective to speed or load variations. This book deals with the analysis, steady state modeling, and control of the wound rotor induction generator that can be used in wind energy applications. Moreover the linear control strategy used is analyzed in terms of all its operating conditions and output quality. The theory was validated via experimental setup to compare theoretical, simulation and practical results to evaluate the usefulness and effectiveness of the system.
One of the most important aspects for large scale integration of wind power systems is the fault ride through (FRT) capability during voltage sags. What this means is that wind turbines should be continuously on-line and supply the grid during voltage sags. Large voltage sags induce high voltages in the rotor circuit of the DFIG and thus the rotor current rises and could exceed the current capability of the converter switches. In the instant of such faults, there is usually a power imbalance between the generator and the grid that usually cause the DC-link voltage rise because of the excess power generated that can not be transferred to the grid. Against the use of crowbar to block the converter and then to disconnect the generator from the grid or by reducing the power generated or maximizing the power supplied to the grid, an active damping criterion in the control of the BtB converter is proposed in this book. The phenomenal increase in these quantities together with other disturbances are by this process rejected and/ or damped thereby making the grid less sensitive to harmonics and oscillations. By this, the wind turbine stays on-line and continues to supply the grid.
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.
Wind energy is potentially attractive because of its low environmental impact and sustainability. This work investigated the wind power production potential in Eldoret, Kenya. Wind speed data over a five-year period (2004-2008) from Eldoret meteorological station are presented. Frequency distributions of wind speeds and wind power densities at three heights, seasonal variations of speed, and estimates of power likely to be produced by small turbines are included.To describe the probability distributions of wind speed, the Weibull distribution function was extensively used in wind resource assessment. It is an analytical function which is found to fit the wind speed curve very well. To assess the wind power potentials, the Weibull parameters were calculated in the analysis of wind speed data.
With the advancement of process technology for fabrication of integrated circuits, the magnitude of variations in process parameters have increased and the parametric yield loss problem has become a serious concern of the fabrication houses. Thus, the traditional techniques for power and delay optimization in design automation tools can no longer be used effectively. This has opened up a challenge to the chip designers to design integrated circuits, which are variation tolerant and thereby having higher parametric yield. In this monograph, a single threshold voltage based approach is proposed that exhibits runtime leakage power reduction comparable to the existing dual threshold voltage assignment approaches and at the same time the proposed approach is less sensitive to process parameter variations. Again, this logic-level runtime leakage reduction technique is combined with multiple supply voltage assignment during high-level synthesis for total power reduction. It is believed that the proposed leakage power reduction technique will be useful in digital circuit design flow (logic-level and high-level syntheses) under process parameter variation.