直流炉机组简化非线性动态模型

以某1000MW超超临界机组为例,基于机理分析并结合机组实际运行数据,通过分析制粉过程、锅炉受热系统、过热器系统和汽轮机的动态特性,建立了直流炉机组在大范围变工况运行下的简化三输入三输出非线性动态模型．该模型以燃料质量流量、总给水质量流量、汽轮机阀门开度为输入,以汽水分离器出口比焓、主蒸汽压力和汽轮机功率为输出．采用机组稳态运行数据确定模型的静态参数,利用负荷变化剧烈的数据辨识动态参数,对模型进行阶跃扰动实验,并与实际运行数据进行对比．结果表明：所建立的模型能够反映机组主要的动态特性和非线性特性,具有结构简单、参数求取容易、复现性好等优点．     

基于遗传算法的转桨式水轮机模型参数辨识

为准确测试转桨式水轮机参数,提出了一种转桨式水轮机数学模型的新表述方法,并探讨了基于遗传算法对新表述数学模型的参数辨识。算例与实际电站参数辨识结果表明,采用辨识参数的模型输出结果与现场实测数据(样本数据)具有较好的一致性,验证了该方法的正确性及在工程实际应用中的可行性,为转桨式水轮机模型参数辨识提供了一种新方法。     

基于迟延估计与Kalman状态跟踪的热工过程动态数据驱动建模

针对常规热工对象历史数据建模过程中稳态数据获取困难的问题,从数据选取、数据处理和方法设计3方面出发,提出一种基于迟延估计与Kalman状态跟踪的热工过程动态数据驱动建模方法。该方法选取动态历史数据作为建模数据,将数据末端输入值作为输入稳态分量,将纯迟延时间及输出的稳态分量作为寻优变量的2个维度,并依据各量的值对数据进行处理;应用Kalman滤波算法获取系统初始状态后,结合智能寻优算法对系统进行建模仿真,对某火电机组高温过热器惰性区进行建模。结果表明:该建模方法能够直接应用系统的动态历史数据进行模型辨识,且所建模型具有较好的模型精度,为动态历史数据建模提供了参考。     

基于功率响应特性的双馈风电场一次调频模型参数全局辨识

随着风电在电力系统中占比提高,其一次调频特性对电力系统频率稳定性的影响增大。为了实现风电场一次调频模型的参数辨识,设计了以实际功率响应数据为依据的辨识方法,基于多工况功率响应数据并采用狼群算法对模型参数进行全局最优辨识。应用所设计的参数辨识方法对某双馈风电场进行了参数辨识,模型仿真值与实测值的对比结果表明：采用该方法辨识得到的模型参数能够较好地反映风电场一次调频功率响应实际特性。     

锅炉燃烧系统的自适应预测函数控制

针对目前电厂锅炉燃烧系统的大滞后、强耦合及变工况等突出问题,提出了一种基于卡尔曼(CARMA)模型的自适应预测函数控制方法,通过实时辨识过程模型的参数,不断去修正预测函数控制器的参数.利用该方法对某电厂锅炉燃烧系统进行了仿真,结果表明:自适应预测函数控制方法对于多输入、多输出过程具有较好的控制效果,是一种计算简单、鲁棒性较强、控制精度高的控制方法.     

混合Box-Jenkins模型交替辨识及在电厂脱硝系统中的应用

混合的Box-Jenkins模型能够较好地表征含噪声干扰系统的特性,针对该模型提出了基于粒子群优化算法的过程模型与噪声模型交替估计辨识方法,避免了常规方法直接对过程模型和噪声模型共同辨识容易陷入局部最优的缺陷。仿真试验表明:交替估计算法可以达到对混合Box-Jenkins模型的精确辨识,其误差约为常规辨识的1/10。为验证方法的实用性,以某电厂机组烟气脱硝系统为对象,建立混合Box-Jenkins模型,利用粒子群算法进行交替辨识,所得过程模型与实际输出基本一致,取得了较好的参数辨识效果,该方法可应用到工业过程中这类系统的参数辨识。     

基于自适应竞争聚类的多输人多输出热工过程模糊辨识

针对多输入多输出（MIM0）热工过程的非线性、强耦合、变工况及参数时变等特点,提出了一种基于系统输入输出数据和模糊自适应竞争聚类的模型辨识新方法．该方法首先依据系统的各个典型运行工况,使用模糊自适应竞争聚类对输入输出数据进行聚类划分,并对T—S模糊模型进行结构辨识,以确定系统的模型结构和参数;然后采用最小二乘递推算法对模型后件参数进行辨识,同时对结构辨识参数进行精确修正．将所提出的模型辨识方法用于锅炉一汽轮机非线性系统的模型辨识,仿真结果验证了该方法的有效性．     

基于参数观测器的不确定混沌电力系统参数辨识

针对混沌电力系统参数辨识存在的稳定性差和易受干扰等问题,提出一种基于未知参数观测器的电力系统参数辨识方法。分析2阶电力系统和4阶电力系统混沌运行状态的数学模型,并分别针对这2种模型的稳定和混沌状态,将电力系统的未知参数看作系统的未知状态,利用非线性状态观测器和稳定性理论,通过构造非线性增益函数和辅助函数得到未知参数观测器,实现混沌电力系统的参数辨识。仿真结果表明该方法具有较好的辨识速度和精度,且具有较好的鲁棒性。     

失速型水平轴风力发电机的气动参数辨识

本文对失速型水平轴风力机气动参数辨识的问题进行了研究。首先利用辨识算法，在假设风轮功率曲线的函数形式已知的前提下，利用测量的输入，输出数据，辨识出功率曲线函数的参数，然后利用辨识出的曲线参数预估系统风轮转速，并与测量的转速对比，以验证辨识模型的准确性。     

风电场等值模型可辨识性研究

研究了风电场等值模型参数的可辨识性,对风电场模型参数的辨识具有重要的理论意义和实用价值。结果表明,利用风电场扰动前、后稳态条件和动态过程,证明了风电场等值模型参数是可唯一辨识的。     

Sensitivity Analysis on Neural Network Algorithm for Primary Superheater Spray Modeling

ABSTRACT

Nonlinear, large inertia with long dead time is always associated with the main steam temperature parameter in coal fired power plant. Successful control of the main steam temperature within ±2°C of its setpoint is the ultimate target for coal-fired power plant operators. Two of the most common main steam temperature circuit are primary superheater spray and secondary superheater spray. Various methods were used to model the primary superheater spray control valve opening, and the neural network remains one of the most popular choices among researchers. It remains inconclusive which neural network algorithm types, setup, number of layers, and training algorithm will give the best result. As such, the paper shows the best setup for the neural network algorithm based on sensitivity analysis methodology for one hidden layer. The inputs selected for the neural network are generator output, main steam flow, total spray flow, and secondary superheater outlet steam temperature, while the output selected is primary spray flow control valve opening.     

燃气轮机余热锅炉饱和蒸汽减温时过热器热力计算特点

在建立减温模型的基础上，分析了减温性能特点及其对过热器热工性能和受热面积布置的影”向；在介绍该模型下过热器热力计算方法的同时，推导了所用重要热工数据的计算公式，并应用于拟定的工程实例中；结合实例计算结果分析，阐明了采用该方法的作用，指出了燃气轮机余热锅炉在拟定计算工况时应结舍当地大气参数变化的特点来进行，从而保证了计算工况的全面性。     

Assessment of the Superheater Ash Fouling Using a Numerical Model of the Superheater

ABSTRACT

Superheaters are high-temperature cross-flow heat exchangers. Steam flows inside the tubes, and the flue gas outside in a direction perpendicular to the axes of the tubes. However, they differ very substantially from the other heat exchangers operating at low temperatures. Superheaters are characterized by complex flow system and high tube walls temperature. Superheaters are among the most exposed to damaging pressure elements of steam boilers. Damage to the superheater causes about 40% of emergency shutdowns of boilers. The paper presents the boiler superheater model with distributed parameters, which is used to determine on-line the degree of superheater fouling by ash.     

Improving Steam Boiler Operation by On-Line Monitoring of the Strength and Thermal Performance

The operation of steam boilers with high efficiency requires control of thermo-hydraulic and strength parameters in the on-line mode. During operation under transient conditions, there are significant temperature differences over the circumference of the horizontal pressure vessels. This occurrence is caused by the different values of heat transfer coefficients on the inner surface of the boiler drum in the water and steam region. Large thermal stresses can occur in partially filled horizontal vessels. This takes place in large steam generator drums, superheater headers, and steam pipelines. The paper presents a method for determination of thermo-flow parameters for steam boilers. This method allows performing the calculations of the boiler furnace chamber and heating flow rates absorbed by superheater stages. These parameters are important for monitoring the performance of the power unit and determining the degree of the furnace chamber slagging. Knowledge of these parameters allows determining the degree of the furnace chamber slagging. The calculation can be performed in online mode and use to monitoring of steam boiler. The presented method allows to the operation of steam boiler with high efficiency.     

500MW机组简化的非线性动态模型

建立火电机组的简化模型，可以为控制系统的设计提供依据，也可以作为一个通用仿真平台用来评价各种控制算法的性能。针对机组负荷／压力对象，依据基本的质量平衡、容积平衡和能量平衡关系，采用机理分析和实验数据拟合相结合的方法，分析制粉过程、锅炉蓄热、过热器差压、汽轮机动态的特点，建立得到机组在大范围变工况运行下简化的非线性动态模型。模型采用机组稳定运行工况点的数据确定静态参数，利用汽轮机调门开度扰动和燃料量扰动实验确定动态参数。实验表明，模型能够反映机组主要的动态特性和非线性特性，具有很好的复现性。图7参9     

Optimization of boiler start-up using a nonlinear boiler model and hard constraints

The basis for control optimization is a nonlinear modeling for a drum-type boiler consisting of furnace, economizer, evaporator, superheaters, attemperator, turbine bypass and thick-walled components such as boiler drum and superheater header. After the mathematical formulation of the boiler start-up optimization problem and of the cost function, including the related hard constraints for inputs and states, the optimal reference and input control are calculated using a multi-stage control vector parameterization method and SQP techniques. The results of this optimization process are optimal reference values and the corresponding input trajectories. The control structures applied minimize both the fuel consumption and start-up time of the boiler.     

基于神经网络的电站锅炉空气预热器积灰在线监测模型研究

针对大型电站锅炉空气预热器受热面积灰状况进行了分析研究。应用3层神经网络构建了300MW电站锅炉空气预热器受热面积灰监测数学模型,选择锅炉负荷、烟气差压、排烟温度等参数作为输入向量,以反映空气预热器积灰状况的污染系数作为输出向量,利用电厂DCS系统采集的机组实时数据,经规格化处理后作为样本集对网络进行训练。训练过程中,通过添加动量项和变步长改进了BP算法。将建立的模型应用于华电国际青岛发电公司#2炉的空气预热器在线积灰监测,取得了较好的结果。     

Mathematical Modeling of Cross-Flow Tube Heat Exchangers With a Complex Flow Arrangement

The general principles of mathematical modeling of heat transfer in cross-flow tube heat exchangers with complex flow arrangements that allow the simulation of multipass heat exchangers with many tube rows are presented. The finite-volume method is used to solve the system of differential equations for temperature of the both fluids and the tube wall with appropriate boundary conditions. A numerical model of a multipass steam superheater with 12 passes is presented. The convection and radiation heat transfer on the flue gas side are accounted for. In addition, the deposit layer is assumed to cover the outer surface of the tubes. Comparing the computed and measured steam temperature increase over the entire superheater allows for determining the thermal resistance of the deposits layer on the outer surface of the superheater. The developed modeling technique can especially be used for modeling tube heat exchangers when detailed information on the tube wall temperature distribution is needed.     

两类过热器壁温分布特性的仿真研究

以一种分布式传热模型为基础,对后屏过热器和高温过热器的壁温分布特性进行了仿真研究.结果表明:这两类过热器的壁温分布特性存在较明显的差异:对于后屏过热器,随着高度方向烟温偏差的增大,各个管圈出口段壁温下降,水平段壁温显著升高;对于高温过热器,当高度方向烟温偏差较小时,壁温最高点位于尾部上升段内,且各点壁温相近;随着这一偏差的增大,壁温最高点逆工质流程向管屏下部移动.     

Dynamic behavior of superheated steam and ways of control

A simple way of calculating the dynamic behavior of a superheater is presented. A comparison of the measured data with the calculated result verifies the accuracy of this simple method. It is the first time that a phase compensation for real roots, i.e., the twin lead/lag loop which is facile for engineering applications, is used in superheated steam temperature control. Numerous simulation results show that both the response time lapse and maximal dynamic deviation are greatly reduced. Moreover, a formula to calculate the setting parameters is presented, together with a practical example of its engineering application in superheated steam temperature control with single-stage attemperation in a power plant boiler. This method can remarkably improve the control performance of superheated steam temperature and makes it possible for one stage attemperation to be sufficient for the superheater of power plant boilers, thus simplifying the superheater system and reducing investment. Because the control performance is remarkably raised, the set values of the steam temperature control system can be raised above rated values and also the operational economy, without impairing the operation safety.