Design calculation of three-loop combined-cycle plants with steam reheating

We describe a procedure for carrying out an end-to-end calculation of the parameters of media and technical and economic indicators of three-loop heat-recovery-type combined-cycle plants with steam reheating that makes it possible to determine the parameters of gases and working fluid of a heat-recovery boiler and the thermal power of its heating surfaces, and to carry out an approximate calculation of the steam turbine for compartments and then for stages at the stage of design calculations using the parameters of gases exhausted from the gas turbine unit as initial data. The procedure is implemented in the form of a computer program in the DELPHI environment and makes it possible to quickly and reliably optimize a combined-cycle plant’s thermal circuit and steam turbine design.     

Selecting the parameters and carrying out design calculations of three-loop combined-cycle plants equipped with a vacuum deaerator and steam reheat system

A procedure for carrying out end-to-end calculation of the parameters of media and technical-and-economic indicators characterizing three-loop heat-recovery combined-cycle plants equipped with a vacuum deaerator and steam reheating system is described. The procedure makes it possible to determine the parameters of gases and working fluid of a heat-recovery boiler, the thermal power of its heating surfaces, and carry out an approximate calculation of the steam turbine and then its stage-wise calculation, all during the design calculation phase.     

Application of the singular perturbation method to a steam power system

A fifth-order steam power system with reheat unit is considered. The discrete model of the continuous system is cast in the singularity perturbed form. A perturbation method is applied to the discrete model. The important features of singular perturbations in discrete systems are clearly illustrated. The numerical values represent a typical set of real data. The results show a new avenue for the application of the singular perturbation method to discrete models of large-scale power systems.     

一种新型控制器在主蒸汽温度控制系统中的应用

利用一种新型非线性比例积分微分（NLPID）控制器进行反馈控制．并与神经网络前馈控制相结合,对传统的主蒸汽温度控制系统进行改进．以提高其适应性和鲁棒性。仿真研究表明,新控制方案比常规比例积分微分（PID）控制表现出更好的控制品质。     

采用H∞性能指标的锅炉过热汽温鲁棒控制

对某超临界600MW直流锅炉高温过热器导前区及惰性区均具有多模型摄动的过热汽温H^∞鲁棒控制问题进行了研究。该被控对象在工况大范围变化时，模型(包括时间常数、增益、甚至对象阶次等)有很大的变化。对此提出了H^∞鲁棒PID汽温控制系统设计方法。讨论了该模型摄动不确定性权函数及性能权函数的选择，求解了H^∞鲁棒PI控制器。该控制器的实现，不需要增加现有控制设备额外的开支。仿真结果表明，设计的汽温控制系统具有较好的鲁棒性能。     

Studying the effect the parameters of steam power cycle have on the economic efficiency and reliability of three-loop combined-cycle plants with steam reheating

We consider the effect the temperatures and pressures in the high- and intermediate-pressure loops have on the economic characteristics of the heat-recovery boiler, steam turbine cylinders, and steam turbine unit of the combined-cycle plant and on the final content of moisture in the steam turbine.     

Advanced control algorithms for steam temperature regulation of thermal power plants

A model-based controller (Dynamic Matrix Control) and an intelligent controller (Fuzzy Logic Control) have been designed and implemented for steam temperature regulation of a 300 MW thermal power plant. The temperature regulation is considered the most demanded control loop in the steam generation process. Both proposed controllers Dynamic Matrix Controller (DMC) and Fuzzy Logic Controller (FLC) were applied to regulate superheated and reheated steam temperature. The results show that the FLC controller has a better performance than advanced model-based controller, such as DMC or a conventional PID controller. The main benefits are the reduction of the overshoot and the tighter regulation of the steam temperatures. FLC controllers can achieve good result for complex nonlinear processes with dynamic variation or with long delay times.     

基于间接能量平衡的锅炉汽温GPC-PID串级控制

针对电站锅炉汽温对象由于存在大惯性、大时滞、非线性和难以建立精确模型,使得传统串级PID控制算法在满足AGC负荷响应快速性和准确性方面存在较大不足等问题,基于直接能量平衡思想,提出一种间接能量平衡法(IEBM)。通过IEBM构造并预测整定出反映变负荷工况的导前汽温设定值,把原串级控制系统中副控制器的随动控制功能改变为定值控制,从而达到间接控制锅炉主汽温和再热汽温的目的。由于系统能及时"预测"到汽温迟延受不同负荷的影响,导前汽温成为控制的主体,采用广义预测控制策略(GPC),而主回路仍然采用PID控制器,构成新型基于多模型RBF神经网络离线辨识的IEBM-GPC-PID串级控制系统。经现场实测数据仿真结果表明,提出的方法能够明显地提升汽温的控制效果,改善控制系统的鲁棒性。     

Tuning of power system stabilizers using genetic algorithms

Several techniques exist for developing optimal controllers. This paper investigates the tuning of power system stabilizers (PSS) using genetic algorithms (GA). A digital simulation of a linearized model of a single-machine infinite bus power system at some operating point is used in conjunction with the genetic algorithm optimization process. The integral of the square of the error and the time-multiplied absolute value of the error performance indices are considered in the search for the optimal PSS parameters. In order to have good damping characteristics over a wide range of operating conditions, the PSS parameters are optimized off-line for a selected set of grid points in the real power (P)-reactive power (Q) domain. The optimal settings thus obtained can then be stored and retrieved on-line to update the PSS parameters based on measurements of the generator real and reactive power. Time domain simulations of the system with GA-tuned PSS show the improved dynamic performance under widely varying load conditions.     

光伏并网逆变器的三环控制策略研究

在光伏并网逆变系统中,常用的双闭环电流控制会导致系统存在动态响应速度慢或开关频率不稳定的缺陷.鉴于此,提出一种电压外环,电流内环,频率中间环的三环控制方法.通过对整个逆变系统进行深入的理论分析,利用Matlab/Simulink搭建仿真模块进行仿真实验,并搭建1 kW的实验平台进行实验分析.实验的结果表明,三环控制下的逆变系统简化了滤波器设计,保证了逆变器输出电流波形质量,使其只含有少量的高次谐波,使系统的输出电流和电网电压同频同向,并网的功率因数接近于1.     

基于脉冲转换温度传感方法的电力设备温度监测系统研究

为了准确测量电力系统中设备关键节点的温度变化,综合考虑绝缘和电磁兼容要求,提出一种基于脉冲转换温度传感芯片的电力设备温度监测系统。该系统采用射频识别技术进行通信,同时采用蒙特卡洛分析法确定了传感器芯片误差修正方法,并提出误差修正公式。最后,在开关柜上进行实际测试。结果显示,本系统可真实反映温度变化,提升了温度测量精度,为准确实现电力设备温度监测提供了一种有效方法。     

Tuning of power system stabilizers using optimization techniques

The application of a numerical optimization scheme to the tuning of power system stabilizers is studied. The scheme is based on minimax optimization techniques with multiple objectives given by relevant system perturbations, aggregated by means of a weighted sum. The large number of constraints is handled by separating the optimization and simulation in two levels which interchange limited information. Three different optimization techniques were tested with applications to the Venezuelan power system for the years 1989 and 2005. The overall method is shown to be accurate and reliable     

用于温度控制系统的计算机数字仿真

把计算机数字仿真技术运用于生产过程的PID控制系统中,实现对控制系统的最优化控制,是信息技术应用于控制系统的一个范例。本文提出一种适用于一般PID控制系统的数字仿真系统的建立方法,并对其数学根据进行了阐述。通过一个在实际PID温度控制系统中应用数字仿真的实例,给出了实际PID控制系统中建立数学模型和实现最优控制的一般方法和技术。并给出了以MCS-51微控制器为核心建立实际PID温度控制系统的技术和方法,此系统的实际控制效果表明:PID控制数字仿真系统对于实际控制系统的控制具有很好的指导意义。     

电厂主蒸汽系统实时仿真模型研究

介绍电厂主蒸汽系统与汽轮机功率，转速全工况实时模型，该模型基于能量，质量，动量守恒方程和水蒸汽物性，考虑了蒸汽的可压缩性，机内实际膨胀过程和调节级及末级组变工况特性的影响，兼顺火电厂锅炉热惯性大，主蒸汽参数高及压水堆型机组主蒸汽参数低，容积流量大的特点，利用图形化流体网络进行求解，仿真结果表明该模型应用范围广，稳态精度高，动态趋势合理，模型适用于电厂全工况范围正常运行和异常事故运行，可为新一代机组的研制提供良好的试验环境。     

Diagnostics of steam turbine disks using the metal magnetic memory method

The possibilities of applying the metal magnetic memory method in combination with ultrasonic examination for diagnosing the main components of steam-turbine rotor disks are considered.     

主蒸汽温度控制系统前馈的优化

针对电网“两个细则”[1]实施下因各电厂提高燃料率的动态超调量对主蒸汽温度控制的影响,基于主蒸汽温度控制动态模型设计了新型主蒸汽温度控制系统的前馈控制器,给出了该控制器的动态配比整定原则和算法,并对该算法进行了模型仿真验证.将前馈控制器用于主蒸汽温度串级控制系统构成主蒸汽温度前馈-串级控制系统,采用该系统对某600 MW机组主蒸汽温度控制系统进行了优化.优化后的控制系统,在机组稳态时主蒸汽温度在±3℃(设定值)的范围内波动;在机组负荷变化率为2.5％MCR时主蒸汽温度在±5℃(设定值)的范围内波动.从而克服了煤量和风量对主蒸汽温度的干扰,消除了“两个细则”实施下提高燃料率的动态超调量对主蒸汽温度的影响.     

基于动态矩阵控制的再热汽温控制系统

预测控制具有良好的动态响应和跟踪性能,但抗干扰性和鲁棒性差.针对火电厂再热器出口温度的大惯性、大延迟的特点,提出了一种改进的动态矩阵控制(DMC)算法,并采用串级控制结构,即内回路采用PID控制快速消除给水流量的扰动,外回路采用带前馈补偿的DMC控制克服蒸汽流量的扰动.将DMC算法和串级控制相结合,充分发挥了PID抗干扰性和DMC对惯性、延迟适应能力强的优点.仿真结果表明,该方案对再热汽温控制系统具有较强的鲁棒性及良好的抗扰动性能,提高了系统的动、静态性能指标,DMC-PID串级控制系统总体性能优于PID-PID串级控制系统.     

电力系统的水力模拟

提出电力系统的水力模拟方法。基于模型与系统物理相似或数学相似的模拟是进行电力系统研究的主要方法。电力系统的水力模拟，则是在数学相似基础上的物理系统模拟。通过分析电力系统与水力系统物理量之间的对应关系及实际问题域和求解过程的相似性。提出应用水力网络进行电力网络模拟的研究方法。给出了一个电力系统水力模拟实例。     

火电厂主汽温系统扰动消除设计方法

火电厂主汽温系统具有大惯性、大延迟和时变等特性,采用常规PID串级控制方法解决主汽温系统的扰动消除问题,结果不甚满意。基于自适应逆控制理论,研究了主汽温系统扰动消除方法,并对实际600MW锅炉高温过热器的动态特性进行了仿真分析。针对主汽温系统导前区和惰性区的内、外2个回路,单独设计相应的扰动消除滤波器,导前区内回路的扰动被从内反馈回路滤波得到的扰动参考信号消除;惰性区输出端扰动从外反馈回路滤波得到扰动参考信号,在对象输入端实现扰动消除。仿真结果表明,该方案可较好地解决主汽温系统存在的内、外扰动问题,对主汽温系统的扰动消除具有较强的鲁棒性和自适应能力。     

模糊RBF自整定PID控制器在过热汽温控制中应用

过热汽温控制是电厂锅炉控制系统的一个重要环节。针对电厂过热汽温对象具有较大的惯性、时滞、非线性和动态特性随运行工况变化的特点,提出一种模糊径向基函数(RBF)神经网络的自整定PID控制器应用于过热汽温控制中,它结合了传统PID及神经网络和模糊控制的优点,可在线调整得到一组最优的PID控制参数。介绍了所提控制器在超临界机组过热汽温控制中的应用。对负荷为100%、88%、62%、44%的仿真结果表明,所提控制器能获得满意结果,优于PID控制器。