650 MW水轮机调节系统非线性模型研究

近年来随着水电的快速发展,各水电站都以大型机组为主,但现有的大部分水轮机调速系统的模型都是针对小机组建立的.重点分析了液压随动系统、引水系统及水轮机存在的非线性因素,建立了650 MW机组的非线性模型.在Matlab/Simulink中搭建了相应的水轮机调节系统非线性仿真模型,并根据云南省某水电厂650 MW机组进行了参数设置,通过仿真实验验证了该模型的准确性.     

The contribution of small hydro power stations to the electricity generation in Greece: Technical and economic considerations

Hydropower is the most widely used renewable energy source worldwide, contributing almost with 18.5% to the fulfillment of the planet electricity generation. However, most locations in Europe appropriate for the installation of large hydro power stations have already been exploited. Furthermore, there is a significant local communities’ opposition towards new large power stations; hence, small hydro power stations remain one of the most attractive opportunities for further utilization of the available hydro potential. Greece and more precisely the country's mainland possesses a significant hydro-power potential which is up to now only partially exploited. In parallel, a large number of private investors have officially expressed their interest in creating small hydro power stations throughout the country, encouraged by the significant Greek State subsidy opportunities for renewable energy applications. However, up to now a relatively small number of projects have been realized, mainly due to decision-making problems, like the administrative bureaucracy, the absence of a rational national water resources management plan and the over-sizing of the proposed installations. Certainly, if the above problems are suitably treated, small hydro-power plants can be proved considerably profitable investments, contributing also remarkably to the national electricity balance and replacing heavy polluting lignite and imported oil. In the context of the above interesting issues, the present study reviews in detail the existing situation of small hydropower plants in Greece and investigates their future prospects as far as the energy, economic and environmental contribution are concerned.     

A 100% renewable electricity generation system for New Zealand utilising hydro,wind, geothermal and biomass resources

The New Zealand electricity generation system is dominated by hydro generation at approximately 60% of installed capacity between 2005 and 2007, augmented with approximately 32% fossil-fuelled generation, plus minor contributions from geothermal, wind and biomass resources. In order to explore the potential for a 100% renewable electricity generation system with substantially increased levels of wind penetration, fossil-fuelled electricity production was removed from an historic 3-year data set, and replaced by modelled electricity production from wind, geothermal and additional peaking options. Generation mixes comprising 53–60% hydro, 22–25% wind, 12–14% geothermal, 1% biomass and 0–12% additional peaking generation were found to be feasible on an energy and power basis, whilst maintaining net hydro storage. Wind capacity credits ranged from 47% to 105% depending upon the incorporation of demand management, and the manner of operation of the hydro system. Wind spillage was minimised, however, a degree of residual spillage was considered to be an inevitable part of incorporating non-dispatchable generation into a stand-alone grid system. Load shifting was shown to have considerable advantages over installation of new peaking plant. Application of the approach applied in this research to countries with different energy resource mixes is discussed, and options for further research are outlined.     

水轮机调节系统被控对象模型辨识

建立了水轮机调节系统被控对象的非线性模型,用递推最小二乘法(RLS)对被控对象进行参数辨识。仿真实验证明,该模型与被控对象模型相吻合、过程简单、效果良好、易于实现编程。基于此对控制参数进行了优化,改善了系统的动态品质。具有实用价值。     

A review on islanding operation and control for distribution network connected with small hydro power plant

Hydro power generation is the oldest generation and provides the largest contribution among the renewable energy types of generation. In distribution system, most of the distributed generation (DG) is small scale hydro generation of which utilizes the natural flowing water of the river. This generation requires governor and excitation control unit to control and sustain the power generation when subjected to any changes of load behavior. More advanced control strategy is critically expected when considering the recent interest in distribution system to perform islanding operation of DG. Many of the literature have clearly highlighted this issue, but only a few have discussed on the islanding operation of small hydro generation. This paper therefore reviews this topic and relates the discussion with the controller designed for other type of turbines interfaced with synchronous generator. To strengthen the knowledge on islanding operation, the background of islanding is also presented in this paper.     

相对轨迹在冲击式水轮机非定常流研究中的应用

从设计角度描述了射流相对轨迹的基本概念,并应用于冲击式水轮机计算流体动力学,特别将相对轨迹的概念与动画解析法相结合预测射流与水斗的各种干涉,以及在不同水斗数、不同比转速和不同射流膨胀率下所对应的损失。结果表明,相对轨迹与计算流体力学的结合是冲击式水轮机优化设计的有效工具。     

在定常流动下混流式水轮机叶片横向振动特性分析

使用一般壳体理论及ALE描述下叶片近壁区流动控制方程，在正交流线坐标系中建立了描述混流式水轮机叶片振动的一般方程，并将叶片在流向与展向的振动对横向振动的影响表示为参数函数，构造出描述叶片横向振动的Mathieu方程，从而可利用数学上熟知的Mathieu方程的特性分析叶片的横向振动。     

On the use of a laboratory-scale Pelton wheel water turbine in renewable energy education

A laboratory-scale Pelton turbine for hydroelectric generation has been constructed and used in the educational curriculum of The Renewable Energy Programme at the University of Jyväskylä. The construction of the Pelton turbine, the experimental apparatus and the measurement procedure are described. The apparatus is simple to make and uses inexpensive components, most of which can be found in standard science laboratories. From the experimental results, the turbine was found to have a maximum mechanical efficiency of 0.47±0.02 for a water flow rate of . The Pelton turbine and apparatus demonstrate the principles of hydropower and are well suited for education in renewable energy.     

Complementarity between solar and hydro power: Sensitivity study to climate characteristics in Northern-Italy

Climate related energy sources such as wind, solar and runoff sources are variable in time and space, following their driving weather variables. High penetration of such energy sources might be facilitated by using their complementarity in order to increase the balance between energy load and generation. This study presents the analysis of the effect of a 100% renewable energy mix composed by solar and run-of-the-river energy in Northern Italy where these two energy sources are the main alternative energy sources. Along a climate gradient from the Alpine crest (snow melt dominated area) to the Veneto plain (rainfall dominated area), solar power is generated in the flat plain, and run-of-the-river hydropower at two mountainous locations. Covering all possible mixes of these two sources, we analyze their complementarity across different temporal scales using two indicators: the standard deviation of the energy balance and the theoretical storage required for balancing generation and load. Results show that at small temporal scale (hourly), a high share of run-of-the-river power allows minimizing the energy balance variability. The opposite is obtained at larger temporal scales (daily and monthly) essentially because of lower variability of solar power generation, which also implies a lower storage requirement.     

Investment planning for electricity generation expansion in a hydro dominated environment

This paper presents the investment planning model, which has been developed to rigorously valorize the large hydroelectric potential resources of Cameroon. Based on Benders technique, the decomposition approach proposed allows each component of the problem (investment and operation) to be conveniently modelled and solved by adapted methods. Furthermore, the relative small size of the actual system, the long experience of the manual generation management in use over a long time by the national electricity company (Sonel), and the fundamental data of the problem are exploited as the basis of the approach, to define a more detailed and adapted model. Formulated as a multistage mixed linear programming problem, the decomposition procedure of the Benders technique is applied to isolate from the problem so modelled its two main subproblems (investment and operation). The investment subproblem is modelled as a multistage mixed linear programming problem and solved by a branch and bound technique. The operation subproblem is represented as a multistage stochastic linear problem and solved by a revised simplex‐based method. Subsequently, a solution algorithm for the whole problem, defined by a finite iterative process where the subproblems are alternatively solved, is derived from the co‐ordination procedure of Benders technique. Case studies with the southern interconnected network of the Sonel system are presented and analysed. Copyright © 2001 John Wiley & Sons, Ltd.     

一种新型两段关闭装置的设计与应用

水轮机导叶两段关闭是抑制甩负荷时发电机组转速与水压升高的最经济有效的措施之一。传统的两段关闭装置管路复杂,渗漏点多,安装、调试十分不便,且其采用滑动活塞结构,容易造成活塞卡塞,出现拒动,威胁水电站安全运行。提出一种新型的两段关闭装置,采用独特的设计和标准的液压元件,克服了上述缺陷,实现了产品标准化,且成本大大降低。电站运行表明：该新型的两段关闭装置功能完善、安装调整方便、可靠性高。     

Contribution of pumped hydro storage to integration of wind power in Kenya: An optimal control approach

This paper investigates the benefit of optimally integrating wind power in Kenya with pumped hydro storage. The approach includes development of an optimal control strategy to deploy paired wind and pumped hydro storage resources, for the Lake Turkana Wind Power project. The stochastic model, which maximizes expected revenue over the planning horizon, is developed taking into the consideration the structure and running of the Kenya electricity market. The 300 MW Lake Turkana Wind Power wind farm is simulated using wind speed data from Marsabit, which is in close proximity to the Lake Turkana region. From the simulation of the wind farm, we find that the daily pattern exhibited by the wind speeds, does not match the average daily load pattern. Pumped hydro storage reduces the systems total power output shortage by 46%. This approach to operation could alleviate the significant economic burden of the take-or-pay purchase agreement that led to the removal of financial backing of the project by the World Bank. The use of pumped hydro storage in conjunction with the wind farm is also found to increase the expected daily revenue of the wind farm by over ten thousand dollars.     

Performance analysis of the airfoil-slat arrangements for hydro and wind turbine applications

Standard airfoils historically used for wind and hydrokinetic turbines had maximum lift coefficients of around 1.3 at stall angles of attack, which is about 12°. At these conditions, the minimum flow velocities to generate electric power were about 7 m/s and 2 m/s for the wind turbine and the hydrokinetic turbine cases, respectively. In this study, NACA4412-NACA6411 slat–airfoil arrangement was chosen for these two cases in order to investigate the potential performance improvements. Aerodynamic performances of these cases were both numerically and experimentally investigated. The 2D and 3D numerical analysis software were used and the optimum geometric and flow conditions leading to the maximum power coefficient or the maximum lift to drag ratio were obtained. The maximum lift to drag ratio of 24.16 was obtained at the optimum geometric and flow parameters. The maximum power coefficient of 0.506 and the maximum torque were determined at the tip speed ratios of 5.5 and 4.0 respectively. The experimental work conducted in a towing tank gave the power coefficient to be 0.47 which is about %7 lower than the numerical results obtained. Hence, there is reasonable agreement between numerical end experimental values. It may be concluded that slat-hydrofoil or airfoil arrangements may be applied in the design of wind and hydrokinetic turbines for electrical power generation in lower wind velocities (3–4 m/s) and current velocities (about 1 m/s).     

冲击式水轮机喷嘴射流的CFD技术

为了研究喷嘴特性对冲击式水轮机性能的影响。在试验的基础上，采用CFD技术对喷嘴自由射流进行多相流的数值模拟。研究结果表明，在相同工况下，不同形状的喷嘴所产生的射流能量特性有明显差异。     

水轮机及其调速系统建模与参数辨识方法

介绍了时域法、频域法和遗传算法等常用的电力系统模型辨识方法。以现场试验数据为基础,分别用PLPF法和遗传算法对水轮机及调速系统进行了参数辨识,结果表明遗传算法能较准确地辨识出系统各个环节的数学模型,仿真曲线更接近实际,体现了遗传算法在非线性模型辨识方面的优越性。     

Effect of size and concentration of silt particles on erosion of Pelton turbine buckets

Erosive wear of hydro turbine runners depends upon different parameters such as size, hardness and concentration of silt particles, velocity of flow, properties of the base material of the turbine components and operating hours of the turbine. Various researchers have conducted experiments to study the effect of these parameters on erosive wear. Most of these experiments were on small-size samples at different types of test rigs to simulate the flow conditions in turbines, however actual flow conditions and the phenomenon of erosive wear are too complex to simulate. Under the present study, effect of these parameters on erosion in actual conditions has been investigated experimentally. An extensive experimental study has been carried out on a small scale Pelton turbine. Based on the experimental data collected for different parameters, correlations have been developed for wear rate of Pelton turbine buckets as a function of critical parameters, i.e., size and concentration of silt particles and jet velocity.     

A simple method to evaluate the technical and economic feasibility of micro hydro power plants in existing irrigation systems

A simple method is proposed to site turbines and choose their power output, evaluate costs and incomes and provide useful indications for Micro Hydro Power (MHP) plant design in existing irrigation systems. This method, based on simple models available in literature and requiring a reduced number of input parameters easy to survey in preliminary design stages, has been applied and verified in an existing irrigation system located in Calabria (Italy).The results have highlighted that in the case study the smallest profitable turbine would produce 5 kW. A lower number of plants (with higher output) would produce no particular monetary savings compared to a greater number of smaller turbines. Furthermore, neither was the option of increasing pipeline diameter found to provide savings.In general, an appreciable potential from MHP operation has been shown in existing irrigation systems, providing a return on investment higher than that provided by the Italian financial market.Finally, MHP profitability noticeably increases with total annual operation time, being on average 55% higher in a wet year (eight months of electrical production/four month of irrigation) compared to a dry year (six months of electrical production/six months of irrigation).     

Study of cavitation in hydro turbines—A review

Reaction turbines basically Francis turbines and propeller/Kaplan turbines are suitable for medium and low head hydropower sites. The management of the small hydropower plants is an important factor, for achieving higher efficiency of hydro turbines with time. Turbines show declined performance after few years of operation, as they get severely damaged due to various reasons. One of the important reasons is erosive wear of the turbines due to cavitation. Reaction turbines, however are more prone to cavitation especially Francis turbines where a zone in the operating range is seriously affected by cavitation and considered as forbidden zone. Cavitation is a phenomenon which manifests itself in the pitting of the metallic surfaces of turbine parts because of the formation of cavities. In the present paper, studies undertaken in this field by several investigators have been discussed extensively. Based on literature survey various aspects related to cavitation in hydro turbines, different causes for the declined performance and efficiency of the hydro turbines and suitable remedial measures suggested by various investigators have been discussed.     

调速器液压系统的故障诊断及可靠控制策略

在分析水轮机微机调速器液压随动系统失效机理的基础上,总结了系统基于专家知识的故障诊断方法,并提出了一种模型参考故障诊断方法．同时应用智能技术将故障诊断与相应的可靠控制策略结合起来,在故障诊断定位的基础上,通过控制策略的变化,消除或弱化故障的影响,达到保证机组安全的目的．仿真研究和工业应用实践充分证明了这些理论和方法的实用性、有效性和可靠性     

水电机组孤网运行频率振荡及其抑制研究

孤网模式下,水电机组调速系统的参数设置不合理会造成频率振荡,从而影响电网可靠运行,因此有必要对调速系统参数与孤网频率稳定性之间的关系进行研究。为此,针对孤网运行的西南某水电机组的实际情况建立了孤网系统模型,并成功仿真出真实存在的频率振荡现象。在此基础上,通过深入分析调速系统人工频率死区、永态转差系数和控制参数对孤网频率稳定性的影响,提出了参数配置建议,并用PSD BPA软件进行了验证。结果表明,合理配置调速系统参数能显著提高水电机组对孤网频率的控制能力,增强孤网系统的稳定性。