【作者】 陈强；

【导师】 郭钰锋；

【作者基本信息】 哈尔滨工业大学 ， 电气工程， 2014， 硕士

【摘要】 目前，世界的水资源趋于紧张，我国更被列为13个贫水国之一。建设大型火力发电厂需要消耗大量的水资源和煤炭资源。空冷机组的凝汽器因用冷却空气来冷却，能够节水65%以上。在我国西北地区，煤炭资源蕴藏丰富而水资源又很缺乏，使得空冷机组具有不错的发展和应用前景。在政策引导下，我国空冷机组建设进入了快速发展期，已经有越来越多的空冷机组投入运行。然而，空冷机组凝汽器的换热过程为表面一次换热，凝汽器的背压受环境因素的影响较大。在背压较高时，空冷机组的发电能力会极大地受到限制，从而影响发出的功率，同时影响电网的频率。在过去空冷机组未大量并网时，这个问题未受到重视。随着空冷机组越来越多的并网，为了保证电力系统的安全和稳定，研究含空冷机组的区域电力系统的调频问题无疑具有重要的意义。首先用GRIDDATA插值处理气象预报数据，得到不同空冷机组所在地的气象信息。然后考虑环境因素的影响，运用机理建模法和辨识法建立了空冷机组的模型和含空冷机组的区域电力系统的调频模型，并在运行点附近将含空冷机组的区域电力系统的模型转化为线性传递函数。在正常工况和特殊工况下，仿真了区域电力系统的频率调节过程。并通过观察伯德图来分析环境温度、迎面风速和空冷机组的功率份额等因素对区域电力系统的频率特性的影响。为了进一步定量的评估环境因素对含空冷机组的区域电力系统调频性能的影响，定义了一次调频能力和二次调频能力为评估指标，推导出其解析式，并通过时域仿真验证了该指标的有效性。在不同环境温度、迎面风速和空冷机组功率份额下，计算出不同因素下的调频能力解析解，拟合出各因素与调频能力的关系式。在调频能力研究的基础上，通过在特殊工况下进行时域仿真分析，确定了空冷机组能够并入区域电网的最大容量和对应的最小调频能力，以此作为检验空冷机组并网是否满足要求的标准。最后提出了改善含空冷机组的区域电力系统调频性能的方法，包括结合数值天气预报进行调度和改变抽汽逆止门的开度的方法，并通过仿真来验证这两种方法是否有效。本文研究工作得到国家重点基础研究发展计划（973计划）（2012CB215201）、国家自然科学基金项目（编号：51107014）以及国家高技术研究发展计划（863计划）重大项目（2011AA05A105）的资助。更多还原

【Abstract】 With the rapid development of power industry, the number of steam turbines oflarge capacity increases, which consumes not only a lot of primary energy but also alot of water resources as well. Water scarcity is the major problem that the world isfacing currently and our country has been listed as one of13water-poor countriesby the United Nations. As air cooling units use cooling air as the cooling medium,the water volume saved by power plants using air cooling technology reaches over65%. Therefore, air cooling units have broad prospects for development andapplication in the northwest regions which are rich in coal and lack water. Under thepolicy guidance, the construction of air cooling units in China has entered a rapiddevelopment period and there have been an increasing number of air-cooling unitsput into operation. However, the heat exchange process of an air cooling unit takesplace in a surface heat exchanger and the backpressure of air cooling condenser willbe greatly affected by environmental factors. Air cooling unit’s generating abilitywill be greatly restricted at high backpressure, thus affecting the power generatedand the frequency of the grid. In the past, this problem wasn’t taken seriously forthere wasn’t much air cooling units connected to the grid. As more and more aircooling units are connected to the grid, to ensure the safe and stable operation ofregional power grid, the study of frequency regulation problem of regional powergrid including air cooling units is needed.Firstly, the meteorological information of the location of air cooling units canbe obtained by processing the weather forecast data using GRIDDATA interpolation.Then the model of regional power grid including air cooling units is constructed bythe mechanism modeling method and identification method on the basis of previousresearch. The model is divided into nonlinear model which is used for simulation inthe time domain and linear model which is used for analysis in the frequencydomain. The simulation in the time domain is the simulation of frequency regulationprocess under the conditions of changing environment temperature and face velocityof cooling air. The analysis in the frequency domain is the analysis of the effects ofenvironment temperature, face velocity of cooling air and power proportion of aircooling unit on the frequency characteristics of regional power systems byobserving the bode diagram of primary frequency regulation and secondaryfrequency regulation. To further quantitatively study the environmental factors’effects on the performances of frequency regulation of regional power grid, theprimary and secondary frequency regulation ability are defined and the analyticalformulas are obtained. By changing the environmental temperature, face velocity of cooling air and power proportion of air cooling units in the power grid, the effects ofthese factors on frequency regulation ability of regional power grid is studied. Theprimary frequency regulation process of regional power grid under specialconditions is simulated in the time domain using Matlab/Simulink software, fromwhich the maximum capacity of air cooling unit connecting to the grid and theminimum value of frequency regulation ability can be evaluated.Finally, the methods to improve the performances of regional power systemincluding air cooling units are proposed, such as dispatching according to numericalweather forecast and change the opening of steam stop valve, the validity of whichare erified by the simulation in the time domain.The research is financed by The National Key Basic Research Program ofChina (973Program)(NO.2012CB215201), The Natural Science Foundation ofChina (NO.51107014) and The National High Technology Research andDevelopment Program (863Program)(NO.2011AA05A105).更多还原