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水轮机调节系统的空载特性仿真 总被引:1,自引:1,他引:0
魏守平 《水电自动化与大坝监测》2009,33(5):20-25
介绍了水轮机调节系统空载动态特性的仿真结果,给出了空载频率波动和空载扰动的仿真曲线.仿真结果有助于加深对水轮机调节系统基本原理的理解,也有助于了解被控制系统参数(调节对象)和水轮机控制系统(调速器)参数对水轮机调节系统空载动态特性的影响. 相似文献
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为了更加全面地了解和掌握水轮机调速系统的组成结构和不同工况下的特性,在大量研究理想条件下水轮机调节系统建模与仿真结果的基础上,对水轮机调节系统进行线性和非线性建模,并运用matlab/simulink对水轮机调节系统的线性和非线性动态特性进行仿真研究,从而得到了线性条件下空载频率波动和功率扰动波动响应曲线以及非线性环节的系统响应,并对这2种条件下的转速和接力器行程曲线进行了对比分析。分析结果表明,在小波动情况下适合运用线性模型,在大波动情况下适合运用非线性模型,而且这2种情况下得到的结果相差无几,均能反映同一系统的动态过程。该结论将有助于水轮机调节系统在不同工况下的控制。 相似文献
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本文从国际电工委员会IEC61362(1998)“水轮机控 制系 统技术规程”中对水轮发电机组甩100%额定负荷后动态品质指标分析入手,运用MATLAB语言 及SIMULINK对水轮机调节系统甩负荷过程建模并进行仿真计算,分析了水轮机调速器典型结 构、调节参数和控制方式对控制性能影响。结果表明:在调速器中引入适当的非线性控制环 节,能够很好地解决大波动到小波动过程的平稳过渡,从而使甩负荷过程性能指标显著提 高;非线性与线性水轮机模型甩负荷仿真曲线的变化趋势相近,因而线性水轮机模型仿真结 果具有代表性。 相似文献
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水轮机调节系统的MATLAB仿真模型 总被引:6,自引:5,他引:1
魏守平 《水电自动化与大坝监测》2009,33(4):7-11
介绍了水轮机调节系统建模及其分析方法.仿真模型是基于MATLAB Simulink建立的,能实现水轮机调节系统空载运行、甩100%额定负荷、接力器不动时间、孤立电网运行和一次调频等动态过程的仿真.仿真结果有助于加深对水轮机调节系统基本原理的理解,也有助于了解被控制系统参数(调节对象)和水轮机控制系统(调速器)参数对水轮机调节系统动态特性的影响. 相似文献
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特征线法及其变体在水轮机及引水系统非线性建模中的对比研究 总被引:1,自引:0,他引:1
建立引水系统的水力变化模型是水电机组非线性建模和仿真中的重要内容,同时水力因素对水轮机调节系统过渡过程的影响也是研究机组和电网稳定性时需要系统性考虑的主要问题。本文提出了一种改进的特征线法,针对水轮机及引水系统建立了包含基本特征线法的联合非线性模型,以及包含可选水击模型的模块化非线性模型,以开展特征线法及其变体的对比研究,为今后水轮机调节系统的大小波动仿真提供一定的理论指导。在此基础上,以国内某大型水电站机组孤网运行模式为例,在频率和负载的大、小扰动作用下,研究了刚性和弹性水击、特征线法及其变体模型的仿真结果,分析了各模型计算的瞬时水头的差别,得出了不同模型参数的调节规律和影响效果。结果表明,在大小波动条件下不同引水系统模型对于机组水头变化趋势的描述基本一致,仅在局部极值附近的计算结果有所差别,且在大波动条件下较为明显,但可通过调整具体的模型参数减小这种差别。 相似文献
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Comparative Evaluation of Genetic Programming and Neural Network as Potential Surrogate Models for Coastal Aquifer Management 总被引:5,自引:3,他引:2
Determining the optimal rates of groundwater extraction for the sustainable use of coastal aquifers is a complex water resources
management problem. It necessitates the application of a 3D simulation model for coupled flow and transport simulation together
with an optimization algorithm in a linked simulation-optimization framework. The use of numerical models for aquifer simulation
within optimization models is constrained by the huge computational burden involved. Approximation surrogates are widely used
to replace the numerical simulation model, the widely used surrogate model being Artificial Neural Networks (ANN). This study
evaluates genetic programming (GP) as a potential surrogate modeling tool and compares the advantages and disadvantages with
the neural network based surrogate modeling approach. Two linked simulation optimization models based on ANN and GP surrogate
models are developed to determine the optimal groundwater extraction rates for an illustrative coastal aquifer. The surrogate
models are linked to a genetic algorithm for optimization. The optimal solutions obtained using the two approaches are compared
and the advantages of GP over the ANN surrogates evaluated. 相似文献
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刘淑娟 《水利与建筑工程学报》2010,8(3):96-100
国内大跨径曲线箱梁多采用悬臂浇筑施工,为了了解其施工过程受力状态及变化规律,该文利用大型空间有限元程序ANSYS和ALGOR建立结构仿真分析数学模型,对变截面曲线箱梁T构的空间受力进行分析,并将仿真分析与实测结果进行对比[1]。结果表明,悬臂施工阶段在自重作用下,在悬臂根部截面内弧侧弯曲应力大于外弧侧,在靠近悬臂端截面则相反,不均匀程度随半径的减小而增加;在悬臂阶段对称布置的预应力作用下,T构应力基本不随曲率半径变化;合拢预应力束产生的正应力在箱梁横截面上明显不对称,半径越小不对称越明显。仿真分析与实测结果基本一致。 相似文献
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在气候变化和人类活动的双重影响下,我国城市洪涝问题日趋严重。在对城市水循环规律深入研究的基础上,开发城市水文水动力模型模拟城市洪涝过程,是弄清城市洪涝致灾机理、减轻洪涝灾害和评估海绵城市减灾效果的重要工具。本文从我国城市洪涝现状和海绵城市建设出发,总结了城市洪涝模拟方法,对水文模型、水动力模型以及二者的耦合机理进行了较为深入的分析,并介绍了目前常用的城市洪涝模拟模型。在此基础上,梳理了当前与城市洪涝模拟相关的热点研究领域,并对其未来发展趋势进行了展望。 相似文献
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《水动力学研究与进展(B辑)》2017,(6)
This paper reviews the numerical models of various cavitating flows around hydrofoils. Numerical models relating to cavitation flows, including mass transfer models and turbulence models, are summarized at first. Then numerical results and analysis of flow characteristics for the cavitating flows around twisted hydrofoils, truncated hydrofoil and tip leakage are discussed respectively. For mean flow fields, Reynolds averaged Navier-Stokes(RANS) simulation associated with a kind of nonlinear turbulence model is found to be an economic and robust numerical approach for different kinds of cavitating flows including cloud cavitation, tip cavitation and tip leakage cavitation. To predict the fluctuations of pressure and velocity, large eddy simulation(LES) and detached eddy simulation(DES) are two effective approaches. Finally, a few open questions are proposed for future research. 相似文献
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Operational modifications at existing reservoir projects can be quite beneficial in responding to changing conditions and intensifying demands on limited resources. Computer simulation models are readily available for analysing reservoir operations. A case study is presented which illustrates a general simulation modelling approach for evaluating reallocation of storage capacity in existing reservoir systems. A set of generalized simulation models, developed by the USACE Hydrologic Engineering Center, are used with monthly hydrologic data. 相似文献
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为了提升水库水位模拟的精度,通过1D CNN-LSTM模型与五种常用的机器学习模型对安徽省红旗水库历史水位数据和降雨量数据实现未来7天的水位模拟并进行对比验证。CNN和LSTM能够表现出比较好的模拟性能,结合两种模型的优势能够更加显著的提升模型的模拟效果;1D CNN-LSTM具有较高鲁棒性,对于未来3天以内水位模拟都有较好的预测效果和精度,虽然3天以后的模拟效果有明显下降,但对未来第7天的模拟NSE和KGE依然能够达到0.8以上,在不发生极端天气的情况下,模型对于水位趋势的模拟依然具有相当的参考价值。1D CNN-LSTM模型对于红旗水库的水位模拟优于其他五种传统的机器学习模型,并具有相当高的精度。 相似文献
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Vladimir M. Shnaydman 《Water Resources Management》1992,6(2):135-148
This is a discussion about constructing simulation models for complex water resources systems (WRS). They are based on the piecewise linear aggregates theory developed in the U.S.S.R. The method allows us to lay down general principles for the construction of such simulation models and automate water resources calculations. Water resources systems simulation models incorporate balance equations, describe water resources inputs into and outputs from sites and reservoirs, and algorithms for both reservoir control and water distribution at sites. Water reservoir control is based on rule curves. The aggregative approach is especially efficient in constructing such algorithms for coordinated control of reservoirs. 相似文献
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