混流式水轮机内特性模型改进及在外特性曲线拓展中的应用

混流式水轮机综合特性曲线反映了水轮机高效率区域的特性,但不满足水轮机大范围内过渡过程仿真需求,在仿真前需要对水轮机低效率及负效率区域的特性进行拓展。目前常用的拓展方法其原理均是根据水轮机综合特性曲线中各参数的变化趋势并结合飞逸特性曲线等约束进行的拓展,没能充分考虑水轮机内在规律,拓展结果过度依赖个人经验,具有较大的随意性。该文通过分析水轮机各部件的能量损失建立了水轮机能量平衡关系式,结合流量调节方程对水轮机内特性模型进行了改进。针对改进后的内特性模型特点设计了一种遗传算法与最小二乘法相结合的参数辨识方法,采用水轮机综合特性曲线及飞逸特性曲线对模型参数进行了辨识,采用辨识后的水轮机模型绘制了较大...

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Bibliographic Details
Published in农业工程学报 Vol. 33; no. 7; pp. 58 - 66
Main Author 门闯社 南海鹏
Format Journal Article
LanguageChinese
Published 西安理工大学水利水电学院,西安,710048 2017
Subjects
参数辨识
模型
混流式水轮机
特性曲线
算法
计算机仿真
过渡过程
models
algorithms
特性曲线
模型
参数辨识
transient process
算法
characteristic curve
过渡过程
混流式水轮机
computer simulation
Francis turbine
计算机仿真
parameter identification
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ISSN1002-6819
DOI10.11975/j.issn.1002-6819.2017.07.008

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Summary:混流式水轮机综合特性曲线反映了水轮机高效率区域的特性,但不满足水轮机大范围内过渡过程仿真需求,在仿真前需要对水轮机低效率及负效率区域的特性进行拓展。目前常用的拓展方法其原理均是根据水轮机综合特性曲线中各参数的变化趋势并结合飞逸特性曲线等约束进行的拓展,没能充分考虑水轮机内在规律,拓展结果过度依赖个人经验,具有较大的随意性。该文通过分析水轮机各部件的能量损失建立了水轮机能量平衡关系式,结合流量调节方程对水轮机内特性模型进行了改进。针对改进后的内特性模型特点设计了一种遗传算法与最小二乘法相结合的参数辨识方法,采用水轮机综合特性曲线及飞逸特性曲线对模型参数进行了辨识,采用辨识后的水轮机模型绘制了较大范围的水轮机特性曲线并与实测特性曲线进行了比对,并结合实测结果对误差来源及误差对过渡过程影响进行了分析。结果表明改进后的混流式水轮机内特性模型能够正确描述水轮机特性,采用最小二乘法与遗传算法相结合的方法能够辨识模型中的参数,将该模型应用在水轮机外特性曲线拓展及过渡过程仿真中,机组过渡过程中最大转速上升率相对误差从2.11%降低到0.54%,最大压力上升率相对误差从10.70%降低到9.52%,说明该模型能够减小仿真误差、减小传统方法中对个人经验的依赖,对过渡过程计算提供了参考。
Bibliography:The combined characteristic curve of Francis turbine shows the performance of turbine working in the high efficiency area. But it isn＇t sufficient for simulating the system transmit process in a large area, such as turbine working in the low efficiency area and negative area in the rejection transient process. Therefore, expanding the combined characteristic curve of turbine to low efficiency and negative efficiency areas is necessary before the simulation. In general, the combined characteristic curve expanding methods, such as frequently used methods of back propagation of artificial neural network method and radial basis function neural network method, are based on the trend of each parameter in the high efficiency area. But the inherent laws in the turbine are not considered in those methods, and the expanding results are relying largely on personal experience. In this paper, the energy loss formulas on each component of turbine, such as guide vane inlet, blade inlet, blade outlet and so on, were obtained
ISSN:1002-6819
DOI:10.11975/j.issn.1002-6819.2017.07.008