A two step optimization algorithm for wind turbine generator placement considering maximum allowable capacity

The wind turbine generation (WTG) sources are generally integrated into network in order to reduce power losses, avoid congestion, improve voltage profile and provide electricity during peak load. Appropriate sizing and sitting of WTGs play a notable role in minimization of the loss in distribution systems. In this paper, a new two-step PSO algorithm is proposed to facilitate placement of WTGs considering their maximum allowable capacity. Also, the location and maximum allowable capacity of WTGs are determined with the aim of minimizing power loss and sustaining the constraints such as bus voltage and loading of feeders in the desired range. In the proposed dual PSO algorithm, there are two steps in each iteration: the first step is implemented in determination of the WTGs optimal location as a control variable, and in the second step, the objective function value is determined among some scenarios which are generated based on the number and capacity of the WTGs, so that all constraints are satisfied. The proposed method feasibility is approved using sample 84-Bus and 32-Bus test systems.     

Fault analysis of wind turbine generators in India

Wind energy has become a techno-economically viable source of energy and is considered as a preferable renewable energy resources option in the power sector in India. If the current pace of development is maintained for at least a few decades, India would soon possess the highest windfarm installation in the world and a significant portion of the country's energy needs could be met through wind power. The available wind energy resource can be utilised to the greater extent by optimally siting the windfarms, by appropriate machine selection and by proper maintenance. An attempt has been made to evaluate the performance of wind turbine generators for the largest demonstration windfarm (10 MW) in Asia. This windfarm is situated at Lamba, Gujarat State with 50 wind turbine machines of 200 kW capacity. The technical availability, real availability, capacity factor and maximum down time of the wind turbine generators have been calculated and plotted over the year. About 30 fault conditions have been identified and analysed by pareto diagram.     

Short-circuit test based maximum likelihood estimation of stabilitymodel of large generators

This paper presents a time-domain statistical identification method for synchronous-machine linear parameters from the standard line-to-line short-circuit test. The measurements are recorded on a 13.75-MVA hydrogenerator at Hydro-Quebec's Rapide-des-Quinze generating station. A complete mathematical model for synchronous machine asymmetrical test analysis is proposed. An efficient algorithm is built to accurately calculate the standard equivalent circuit from time-constants and operational inductances. The maximum likelihood estimator derived from the generalized least-squares method is then used for parameter identification. Validation of the estimated model response against the measured running-time domain data confirms the effectiveness of the proposed estimation technique     

大型汽轮发电机通风系统研究综述

为满足汽轮发电机不断地向大型化发展地需要，必须对大型汽轮发电机的通风系统进行优化设计，以提高其通风冷却效果。为此，国内外对影响汽轮发电机通风冷却状况的主要因素如冷却介质的流动与传热特性、不同通风系统的通风计算方法、通风系统的结构等进行了一系列理论分析和试验研究，并取得不少具有实际应用价值的成果。在对现有成果的分析和总结的基础上，指出了有待进一步研究之处。     

Aeroelastic design of large wind turbine blades considering damage tolerance

Modern offshore turbine blades can be designed for high fatigue life and damage tolerance to avoid excessive maintenance and therefore significantly reduce the overall cost of offshore wind power. An aeroelastic design strategy for large wind turbine blades is presented and demonstrated for a 100 m blade. High fidelity analysis techniques like 3D finite element modeling are used alongside beam models of wind turbine blades to characterize the resulting designs in terms of their aeroelastic performance as well as their ability to resist damage growth. This study considers a common damage type for wind turbine blades, the bond line failure, and explores the damage tolerance of the designs to gain insight into how to improve bond line failure through aeroelastic design. Flat‐back airfoils are also explored to improve the damage tolerance performance of trailing‐edge bond line failures. Copyright © 2016 John Wiley & Sons, Ltd.     

大型汽轮发电机通风冷却方式研究

大容量汽轮发电机由于具有良好的经济性而成为电力工业和电机制造业的发展重点。汽轮发电机通风冷却方式与单机容量和性能之间存在制约的关系，是汽轮发电机向大容量、高参数发展时需要解决的关键问题之一。分析了汽轮发电机冷却方式的发展过程以及目前的发展状况和发展趋势，同时对不同冷却方式的特点和适用范围的进行了比较。     

Optimum siting of wind turbine generators

This paper investigates optimum siting of wind turbine generators from the viewpoint of site and wind turbine generator selection. The methodology of analysis is based on the accurate assessment of wind power potential of various sites. The analytical computations of annual and monthly capacity factors are done using the Weibull statistical model using cubic mean cube root of wind speeds. As many as fifty-four potential wind sites, with and without wind turbine installations, geographically distributed in different states of India are used for the siting analysis. As an outcome of this analysis several definitive conclusions of archival nature have been arrived at and are presented in the paper. If this analysis is done at the planning and development stages of installation of wind power stations, it will enable the wind power developer or the power utilities to make a judicious choice of potential site and wind turbine generator system from the available potential sites and wind turbine generators respectively     

Design performance analysis of pressurized solid oxide fuel cell/gas turbine hybrid systems considering temperature constraints

This study presents critical aspects and their influence on the performance of hybrid power systems combining a pressurized solid oxide fuel cell (SOFC) and a gas turbine (GT). Two types of hybrid system configurations with internal and external reforming have been analyzed. In order to examine the effect of matching between the fuel cell temperature and the turbine inlet temperature on the hybrid system performance, we considered air bypass after the compressor as well as additional fuel supply to the turbine side. This study focuses on the limitation of the temperature difference at the fuel cell stack and its influence on the performances of the two hybrid systems. Performances of the hybrid systems are also compared with those of simple SOFC systems, and the extent of performance enhancement is evaluated. The system with internal reforming gives better efficiency and power capacity for all design conditions than the system with external reforming under the same constraints. Its efficiency gain over the SOFC only system is considerable, while that of the system with external reforming is far less. As the temperature difference at the cell becomes smaller, the system performance generally degrades. The system with internal reforming is less influenced by the constraint of the cell temperature difference.     

A nomogram method for estimating the energy produced by wind turbine generators

A simple nomogram is constructed to estimate the power generated by a wind turbine generator (WTG) operated at near maximum efficiency using optimum tip-speed ratio between cut-in and rated wind speed, and at constant power using optimum pitch control between rated and cut-out wind speed. The nomogram is based on information that is readily available for commercial WTGs as well as some simple statistical quantities for the wind at the site. When the wind speed is described by a Weibull distribution, the power of a WTG is estimated in terms of three generalized non-dimensional parameters. When a Rayleigh distribution is employed only two parameters are necessary. A second nomogram is also developed for those less common cases where a small correction of the results of the first nomogram is needed. A mathematical analysis is presented which allows for the construction of single chart nomograms without sacrificing the necessary accuracy. Two application examples demonstrate the degree of accuracy achieved by the nomograms and the advantages they offer for parametric analyses as regards convenience and labor.     

风电场风机初步选型方法研究

市场上可供选择的风机种类众多,各类风机在性能、价格、维修及制造商服务等多方面都存在明显差异,因此在选择风机时有必要综合考虑多方面因素。鉴于工程上对风机作初步选型时采用的方法大多具有局限性,文章在确定影响风机选型的主要因素后提出一套风机初步选型方法,该方法根据拟建风电场的情况和设计人员的要求,综合考虑各因素后选出符合条件的风机。文章基于该选型方法将Visual Basic语言与Microsoft Access数据库相结合,开发出相应的选型系统,使整个选型过程更为方便、快捷。     

Wind power analysis and site matching of wind turbine generators in Kingdom of Bahrain

In this paper, the hourly measured wind speed data for years 2003–2005 at 10 m, 30 m and 60 m height for Kingdom of Bahrain have been statically analyzed to determine the potential of wind power generation. Extrapolation of the 10 m data, using the Power Law, has been used to determine the wind data at heights of 30 m and 60 m. Weibull distribution parameters have been estimated and compared annually and on monthly bases using two methods; the graphical method and the another method, designated in this paper as approximated method, which depends on the standard deviation and average wind speed. The maximum power density for 10 m, 30 m and 60 m heights were found to be 164.33 W/m², 624.17 W/m² and 1171.18 W/m² in February, respectively while the minimum power density were 65.33 W/m², 244.33 W/m² and 454.53 W/m² in October, respectively. The average annual wind power density was found to be 114.54 W/m² for 10 m height, 433.29 W/m² for 30 m height and 816.70 W/m² for 60 m height. Weibull probability function, using Weibull parameters estimated from the approximated method, has shown to provide more accurate prediction of average wind speed and average power density than the graphical method. In addition, the site matching of wind turbine generators at 30 m and 60 m heights has been investigated by estimating the capacity factors of various commercially available wind turbines generators. The monthly and annual variation of capacity factors have been studied to ensure optimum selection of wind turbine generators.     

Design of a wind turbine rotor for maximum aerodynamic efficiency

The design of a three‐bladed wind turbine rotor is described, where the main focus has been highest possible mechanical power coefficient, CP, at a single operational condition. Structural, as well as off‐design, issues are not considered, leading to a purely theoretical design for investigating maximum aerodynamic efficiency. The rotor is designed assuming constant induction for most of the blade span, but near the tip region, a constant load is assumed instead. The rotor design is obtained using an actuator disc model, and is subsequently verified using both a free‐wake lifting line method and a full three‐dimensional Navier–Stokes solver. Excellent agreement is obtained using the three models. Global CP reaches a value of slightly above 0.51, while global thrust coefficient CT is 0.87. The local power coefficient C_p increases to slightly above the Betz limit on the inner part of the rotor; the local thrust coefficient C_t increases to a value above 1.1. This agrees well with the theory of de Vries, which states that including the effect of the low pressure behind the centre of the rotor stemming from the increased rotation, both C_p and C_t will increase towards the root. Towards the tip, both C_p and C_t decrease due to tip corrections as well as drag. Copyright © 2008 John Wiley & Sons, Ltd.     

Matching of DC motors to photovoltaic generators for maximum dailygross mechanical energy

The matching to solar-cell generators of both separately excited and series DC motors driving pumping loads is addressed. It is shown that the maximum gross mechanical power can be obtained at slightly higher voltages and slightly lower currents compared to the maximum electrical-power points on the solar-cell generator characteristics at different insolation levels. Guidelines for constructing the loci of the motor voltage-current points for maximum mechanical power and for determining the optimal motor parameters to match the solar generator are derived in terms of the mechanical load characteristics and the solar array parameters. Results of applying these design criteria to practical case studies enabled the assessment and comparison of both kinds of motors, especially as far as the daily utilizable output mechanical energy is concerned. The superiority of the separately excited motors in such systems is quantitatively indicated. The results are also compared to corresponding information available in the literature     

A new control methodology of wind turbine generators for frequency control of power system in isolated island

A wind turbine generator (WTG) system's output is not constant and fluctuates depending on wind conditions. Fluctuating power causes frequency deviations and adverse effects to an isolated power system when large output power from WTG systems is penetrated in the power system. This paper presents an output power control methodology of a WTG for frequency control using a load power estimator. The load power is estimated by a disturbance observer, and the output power command of the WTG is determined according to the estimated load. Besides, the WTG can also be controlled during wind turbulence since the output power command is determined by considering wind conditions. The reduction of the power system frequency deviation by using the WTG can be achieved by the proposed method. The effectiveness of the proposed method is validated by numerical simulations. Copyright © 2010 John Wiley & Sons, Ltd.     

防止风电机组连锁脱网事故的动态无功备用需求分析

对风电机组连锁脱网事故的调查表明,双馈风电机组触发Crowbar保护进入低电压穿越区需要从电网吸取大量的无功,造成风电场电压进一步恶化。文章对大型风电场的无功需求和运行状况进行深入分析,推导出大型风电场的临界运行电压和无功备用容量计算公式,为风电场无功电压协调控制提供理论支撑。采用酒泉风电基地的实际算例进行了仿真分析,结果表明,风电场机组处于鼠笼异步运行状态时需要从电网吸收大量无功,同时风电场周边场站电压下降明显;而当动态无功备用容量达到临界动态无功备用容量及以上时,则能有效地改善风电场相关站点的电压分布。     

Optimization of heat recovery steam generators for combined cycle gas turbine power plants

The heat recovery steam generator (HRSG) is one of the few components of combined cycle gas turbine power plants tailored for each specific application. Any change in its design would directly affect all the variables of the cycle and therefore the availability of tools for its optimization is of the greatest relevance. This paper presents a method for the optimization of the HRSG based on the application of influence coefficients. The influence coefficients are a useful mathematical tool in design optimization problems. They are obtained after solving the equations of the system through the Newton–Raphson method. The main advantage of the proposed method is that it permits a better understanding of the influence of the design parameters on the cycle performance. The study of the optimization of the distribution of the boiler area between its different components is presented as an example of the proposed technique.     

Recent development of large electrolytic hydrogen generators

An overview of the history and market of large electrolysis units is presented. The historical background introduces and explains the thought process behind a new design of Teledyne's Electra Cell alkaline electrolysis hydrogen generators.The new design enables construction of modules capable of 1.6 ton per day of hydrogen. The cost of hydrogen is used as a criterion for the selection of optimum performing cells as a function of user parameters. It is suggested that due to cell costs, the highest efficiency cell does not always produce the cheapest hydrogen.     

大型风力发电机旋转叶片结构动力特性分析

大型风力发电机叶片的结构动力特性是叶片结构设计时考虑的重要方面,其固有自振频率对于整个风力机的安全运行具有重要意义。文章基于现代柔性多体动力学理论和有限元数值分析相结合的方法,对5MW风力发电机叶片的固有振动特性进行分析。结合复合材料叶片结构特性及结构参数,建立了5 MW风机复合材料叶片有限元模型,计算了考虑动力刚化及阻尼效应影响下的固有频率和振型,揭示了动力刚化效应对叶片固有频率的影响规律;并结合坎贝尔图,对叶片进行了共振分析,为叶片的结构设计及优化提供了参考依据。     

Performance analysis of a syngas-fed gas turbine considering the operating limitations of its components

As the need for clean coal technology grows, research and development efforts for integrated gasification combined cycle (IGCC) plants have increased worldwide. An IGCC plant couples a gas turbine with a gasification block. Various technical issues exist in designing the entire system. Among these issues, the matching between the gas turbine and the air separation unit is especially important. In particular, the operating condition of a gas turbine in an IGCC plant may be very different from that of its original design. In this study, we analyzed the impact of the use of syngas on operating conditions of the gas turbine in an IGCC plant. We evaluated the performance of a gas turbine under operating limitations in terms of compressor surge and turbine metal temperature. Although a lower degree of integration may theoretically allow higher gas turbine power output and efficiency, it causes a reduction in compressor surge margin and overheating of the turbine metal. The turbine overheating problem may be solved using several methods, such as a reduction in the firing temperature or an increase in the turbine cooling air. The latter yields a much smaller performance penalty. To achieve an acceptable margin for the compressor surge, either further reduction in the firing temperature or further increase in the coolant is required. Ventilation of some of the nitrogen generated by the air separation unit, i.e., a reduction of the nitrogen supply to the combustor, is another option. Coolant modulation yields the lowest performance penalty. Reduction of the nitrogen supply provides much greater system power output than control of the firing temperature. For nitrogen flow and firing temperature controls, there are optimal levels of integration degrees in terms of net system power output and efficiency.