热力机组系统热经济性矩阵向量分析法

以火电机组热力系统状态方程为基础推导得出各种辅助汽水扰动下的热经济性分析通式。提出系统增益向量及热扰动向量的概念及构造计算方法。基于热力系统热经济状态方程的向量分析法与传统理论方法假设基础相同,即都假定系统状态参数保持不变,因此二者的适用范围相同。但前者经过推导变换统一了分析思路和计算手段,对满足假设条件的各类扰动分析普遍适用,概念清楚、简捷易用。     

多输入、输出耦合系统的改进线性自抗扰控制及参数整定方法

针对火电机组燃烧系统耦合性强、工况复杂、强扰动和参数调节困难的问题,在现有线性自抗扰控制(LADRC)基础上,提出一种改进线性自抗扰控制(ILADRC)。首先,根据热工系统大时滞、大惯性的特点,在LADRC线性扩张状态观测器(LESO)控制输入端串联惯性时滞前馈补偿器,实现LESO前馈和反馈信号同步,提升信号跟随和扰动抑制性能;然后,通过开环频域稳定性分析得出系统稳定性指标和控制器参数关系,进而推导出基于系统稳定性指标的定量化参数整定规则,简化参数调节过程。将所设计的ILADRC应用于火电机组床温和主蒸汽压力耦合控制仿真系统,并与比例积分微分(PID)控制、LADRC、模型辅助线性自抗扰控制(MLADRC)进行对比。结果表明：提出的ILADRC在定值跟随、扰动抑制方面具有明显优势,蒙特卡洛试验进一步证明了所提出ILADRC的鲁棒性优势。     

火电机组的热经济性分析

为进行整个火电机组的能量系统热经济性分析及考察其组元变化的影响，提出了以热经济学和边际成本概念为基础的热经济性分析方法。对复杂能量系统主要以功能划分后形成的组元，考察其组元的输出炯流变化引起整个系统的能耗变化，可以通过边际炯成本、单位炯成本和组元产品的函数来表达，来衡量整个系统所有组元的输出炯流变化对系统外部输入燃料的影响，便于火电机组的运行经济状态动态评估。通过300MW机组主蒸汽参数变化的计算表明：参数变化时将引起系统的煤耗增加，降低了经济性，因而从本质上进行了热经济性的全面综合分析，以优化机组运行，进行性能诊断。图1表2参10     

大型火电机组热力系统变工况经济性分析

基于热力系统的小扰动理论,在热系统变工况计算中考虑汽轮机内汽态膨胀线变化,建立了大型火电机组热力系统变工况计算的数学模型。利用该模型计算得到了主蒸汽温度、主蒸汽压力、真空、再热汽温度、过热器喷水量和再热器喷水量发生扰动时,对机组效率和标准煤耗的定量影响。结果表明,主汽温度、再热汽温度、过热器喷水、再热器喷水的影响基本呈线性关系,而主汽压力和汽轮机真空对机组的影响则是非线性的。     

A modern method for analyzing thermal energy system with system state equation and analytical formula of performance index

This paper addresses overall performance analysis of coal-fired power unit.From the point of view of system en-gineering,a general steam-water distribution equation of the thermal plant system is presented.This system stateequation is an exact expression combining system topological structure and system properties.Through propermathematic transform,the inner relationship and interaction between the main system and auxiliary system arerevealed and its general form is given.An analytical formula for the heat consumption rate of thermal power plantis one direct fruit of the equation,which greatly facilitate the online analyzing and optimizing of complex thermalsystem.The new approach,with the aid of modern data acquiring technology,is a perfect extension of the tradi-tional analysis method based on the First Law of Thermodynamics.     

Modeling of a pressure modulated desalination system using bond graph methodology

A desalination system is a complex multi energy domain system comprising power/energy flow across several domains such as electrical, thermal, and hydraulic. The dynamic modeling of a desalination system that comprehensively addresses all these multi energy domains is not adequately addressed in the literature. This paper proposes to address the issue of modeling the various energy domains for the case of a single stage flash evaporation desalination system. This paper presents a detailed bond graph modeling of a desalination unit with seamless integration of the power flow across electrical, thermal, and hydraulic domains. The paper further proposes a performance index function that leads to the tracking of the optimal chamber pressure giving the optimal flow rate for a given unit of energy expended. The model has been validated in steady state conditions by simulation and experimentation.     

Integration of a fuel cell into the power system using an optimal controller based on disturbance accommodation control theory

In this paper, the integration of a fuel cell into the power system is treated as a load frequency control (LFC) problem with the fuel cell acting as a load disturbance source. The integration of a fuel cell into the power system results into a change in real power. But changes in real power affect the system frequency. Thus, the integration will result into a change of frequency of the synchronous machines. Hence, we need to design a control scheme for keeping the system in the steady state. An optimal controller based on the disturbance accommodation control (DAC) theory is proposed for this load frequency control problem. For demonstrating the effectiveness of the proposed controller, we have considered a two-area power system with the fuel cell introduced in area 1. The fuel cell is considered as an external disturbance to each subsystem. A mathematical model is derived for each subsystem and based upon these models controllers are designed for keeping each subsystem stable, which in turn stabilizes the overall system. So, the proposed controller is decentralized in nature. To account for the modeling uncertainties, an observer is designed to estimate each subsystem’s own and interfacing variables. The controller uses these estimates to optimize a given performance index and allocate generating unit outputs according to the requirements.     

汽轮机及热装置性能评估系统研究

以某石化电厂双抽凝汽式汽轮机及热系统为研究对象,开发了以“热力参数诊断”为中心的旋转机械热力性能评估体系。通过对该汽轮机组运行性能和经济性能的计算分析,实时显示汽轮机组工作状态、当前热经济指标、当前工况下的节能潜力及热设备能损诊断结果,提出优化运行建议,并从热力学角度为电站设备的状态监测和预知性维修提供科学依据,实时指导汽轮机组经济运行。     

Performance improvement of a slip energy recovery drive system by a voltage-controlled technique

This paper introduces the performance improvement of a slip energy recovery drive system for the speed control of a wound rotor induction motor by a voltage-controlled technique. The slip energy occurred in the rotor circuit is transferred back to ac mains supply through a reactor instead of a step up transformer. The objective of the voltage-controlled technique is to increase power factor of the system and to reduce low order harmonics of the input line current. The drive system is designed and implemented using a voltage source inverter in conjunction with a boost chopper for DC link voltage, instead of a conventional drive using a 6 pulse converter or a Scherbius system. The slip power is recovered by the help of a voltage source inverter (VSI) based on a space vector pulse width modulation (SVPWM) technique. In order to keep the speed of the wound rotor induction motor constant over a certain range of operating conditions, the servo state feedback controller designed by a linear quadratic regulator (LQR) is also introduced in this paper. The overall control system is implemented on DSP, DS1104’TMS320F240 controller board. The performance improvement of the proposed system is tested in comparison with the conventional Scherbius system and the modified conventional Scherbius system by a 12 pulse converter in conjunction with a chopper at steady state and at dynamic conditions. A 220 W wound motor is employed for testing. It is found that the motor speed can be controlled to be constant in the operating range of 450–1200 rpm at no load and full load. It is also found that the efficiency of the proposed system is remarkably increased since the harmonics of the input ac line current is reduced while the ac line input power factor is increased.     

火电机组一次调频性能实时监测系统

为了实时监测和评价火电机组一次调频性能,开发了火电机组一次调频性能实测监测系统。该系统具有一次调频参数异动感知、一次调频性能量化预测及自适应校正等关键功能。某机组的实际应用表明,该系统能够实现火电机组一次调频关键参数的实时监测和调频性能的准确预测。     

Artificial neural network power system stabilizers in multi-machinepower system environment

The effectiveness of an artificial neural network (ANN), functioning as a power system stabilizer (PSS), in damping multi-mode oscillations in a five-machine power system environment is investigated in this paper. Accelerating power of the generating unit is used as the input to the ANN PSS. The proposed ANN PSS using a multilayer neural network with error-backpropagation training method was trained over the full working range of the generating unit with a large variety of disturbances. The ANN was trained to memorize the reverse input/output mapping of the synchronous machine. Results show that the proposed ANN PSS can provide good damping for both local and inter-area modes of oscillations     

多能源数据驱动的电力信息物理系统综合态势感知模型

针对高比例可再生能源以及多类型能源设备接入的电网,以电力信息物理融合为基础,研究面向可靠性评估的电力信息物理系统运行状态综合分析方法,提出多能源数据驱动的电力信息物理系统综合态势感知模型。首先,考虑电力信息物理系统中影响系统运行状态的关键因素,研究面向可靠性评估的电力信息物理系统运行状态变化过程;其次,针对电力信息物理系统不同运行状态下关键设备扰动问题,研究基于改进鲁棒估计的电力信息物理系统正常状态、临界状态、紧急状态和恢复状态辨识方法,在此基础上,建立多能源数据驱动的电力信息物理系统综合态势感知模型;最后,以东北某地区电网运行数据为例进行验证。仿真结果表明,文章所提出的方法能够实现以可靠性辨识为目标的电力信息物理系统综合态势感知,并能保证较高的准确性和实时性。     

A reliable and practical reference objective for the deviation diagnosis of energy system parameters

The core objective to optimize a complex energy system is to set the reference target to guide the parameter adjustment of system operation. In this paper, a new case-based approach is proposed based on an online performance assessment program and its long-term operation data for a large power unit. The online model of a coal-fired power unit’s performance assessment is demonstrated, and the distribution pattern of the performance index is revealed by statistical analysis of the abundant data. The fundamental issues (representation of the similarity of two thermal processes, similarity measure, etc.) are tackled. The key sections and key parameters for the completion of similarity determination are proposed, which are essential to realize a case-based strategy. A full-scope simulator of power unit is used to test the availability of the method. The advantage of the case-based approach is the integrality of information over other methods.     

Optimal generation scheduling in power system using frequency prediction through ANN under ABT environment

In a competitive and deregulated power scenario, the utilities try to maintain their real electric power generation in balance with the load demand, which creates a need for the precise real time generation scheduling (GS). In this paper, the GS problem is solved to perform the unit commitment (UC) based on frequency prediction by using artificial neural network (ANN) with the objective to minimize the overall system cost of the state utility. The introduction of availability-based tariff (ABT) signifies the importance of frequency in GS. Under-prediction or over-prediction will result in an unnecessary commitment of generating units or buying power from central generating units at a higher cost. Therefore, an accurate frequency prediction is the first step toward optimal GS. The dependency of frequency on various parameters such as actual generation, load demand, wind power and power deficit has been considered in this paper. The proposed technique provides a reliable solution for the input parameter different from the one presented in the training data. The performance of the frequency predictor model has been evaluated based on the absolute percentage error (APE) and the mean absolute percentage error (MAPE). The proposed predicted frequency sensitive GS model is applied to the system of Indian state of Tamilnadu, which reduces the overall system cost of the state utility by keeping off the dearer units selected based on the predicted frequency.     

A reliable and practical reference objective for the deviation diagnosis of energy system parameters

The core objective to optimize a complex energy system is to set the reference target to guide the parameter adjustment of system operation. In this paper, a new case-based approach is proposed based on an online performance assessment program and its long-term operation data for a large power unit. The online model of a coal-fired power unit’s performance assessment is demonstrated, and the distribution pattern of the performance index is revealed by statistical analysis of the abundant data. The fundamental issues (representation of the similarity of two thermal processes, similarity measure, etc.) are tackled. The key sections and key parameters for the completion of similarity determination are proposed, which are essential to realize a case-based strategy. A full-scope simulator of power unit is used to test the availability of the method. The advantage of the case-based approach is the integrality of information over other methods.     

基于C/S模式的火电机组耗差分析系统

利用火电厂现有的信息资源，开发了Client/Server模式下的火电机组耗差分析系统，该系统采用了先进的数学模型和模块化思想，具有在线计算准确性高、运行维护方便、节约火电厂计算机资源等优点。该系统实现了热力试验的自动进行，这就极大地减少了火电厂用于热力试验方面的开支。实践表明，该系统的投运能为现场运行人员提供一个明确的运行调整方向，以确保机组始终处于经济运行状态。     

Performance of low temperature solar rankine power generation system

The overall performance of a solar thermal electrical power generation system is governed by the performance of the energy collection system and the power conversion unit. Any system operating under given meteorological and solar radiation conditions has a unique energy collection temperature for which the electrical output of the system will be a maximum. An engineering analysis of the system was carried out to obtain general correlations which can be used for determining such an optimum temperature. Factual experience on the design and operation of a Rankine system, using flat plate collectors and the climatological data, was used to obtain numerical estimates for the net energy conversion capability of such systems operating in Kuwait.     

Nonlinear multivariable modeling of locomotive proton exchange membrane fuel cell system

A nonlinear multivariable model of a locomotive proton exchange membrane fuel cell (PEMFC) system based on a support vector regression (SVR) is proposed to study the effect of different operating conditions on dynamic behavior of a locomotive PEMFC power unit. Furthermore, an effective informed adaptive particle swarm optimization (EIA-PSO) algorithm which is an adaptive swarm intelligence optimization with preferable search ability and search rate is utilized to tune the hyper-parameters of the SVR model for the improvement of model performance. The comparisons with the experimental data demonstrate that the SVR model based on EIA-PSO can efficiently approximate the dynamic behaviors of locomotive PEMFC power unit and is capable of predicting dynamic performance in terms of the output voltage and power with a high accuracy.     

原动机周期性扰动引发强迫功率振荡特性研究

大型水电、火电集中外送系统存在的功率振荡是中国能源外送面临的突出难题,严重限制了外送功率的提升。近年来,实际电网中多次发生强迫功率振荡,前期研究表明,原动机周期性扰动很容易引起电网强迫功率振荡。结合计及原动机调速系统的Phillips-Heffron模型,分析得出共振时扰动源机组的机械负阻尼转矩系数KRE为较大正值;同时进行能量分析,振荡时扰动源机组的势能与非扰动源机组的势能变化呈现明显不同的增长趋势。因此,结合发生强迫功率振荡时各机组的转矩和能量性质,能够实现对原动机周期性扰动类型扰动源的定位。     

日本松浦发电厂2号机组的湿法烟气脱硫

介绍了1997年7月建成的日本松浦火力发电厂2号机组的湿法烟气脱硫装置。装置应用脱硫氧化、除尘系统，减少了占地面积，简化了工艺和控制设备。系统配置1000MW容量的吸收塔，其喷淋塔是世界上最大的。通过对装置试运行的性能测试和计算表明，系统运行良好，达到了设计要求。