抽水蓄能机组停机过程仿真及优化

抽水蓄能机组出口断路器通过合、分闸操作来控制抽水蓄能机组的启停及运行工况的切换,影响着抽水蓄能系统的运行情况;抽水蓄能机组出口断路器开断电流的大小决定其触头损耗的多寡,开断电流的减少可减缓断路器的损耗,延长其使用周期。通过建立抽水蓄能机组仿真模型,研究发电与抽水工况停机过程中有功和无功功率对断路器开断电流的影响,根据仿真结果,选取最优电压调节器放大倍数和最小导叶开度,优化停机流程,达到了减少断路器开断电流的目的。     

混合式抽水蓄能电站过渡过程研究

为了适应电网发展的需求,具备一定地形地质条件的常规水电站可考虑通过增装蓄能机组扩建成混合式抽水蓄能电站。针对共用引水系统的常规机组和蓄能机组实际运行特点,基于特征线法和瞬变流理论,建立了水力过渡过程计算模型,并结合工程实例模拟了混合式抽水蓄能电站可能发生的多种过渡过程工况,确定了合理的蓄能机组的关闭规律,复核了已建调压室的稳定性。结果表明,通过对新增蓄能机组导叶启闭规律的独立调控,一定程度上可维持混合式抽水蓄能电站输水发电系统的安全稳定,避免增设调节保证设施;蓄能机组导叶关闭时间延长,在降低自身蜗壳末端最大压力的同时,可抑制常规机组甩负荷后的蜗壳末端压力及最大转速上升;对于既有调保措施威胁最大的相继增负荷工况,引用流量较大的常规机组优先增负荷比引用流量较小的蓄能机组优先增负荷引起的调压室最低涌浪值更高,更有利于调压室的稳定运行。     

基于精细化模型的水泵断电工况导叶关闭规律多目标优化

为提高可逆式抽水蓄能机组水泵断电工况过渡过程动态品质,提出一种基于抽水蓄能机组精细化模型的导叶关闭规律多目标优化策略,即先建立能精确反映各水力单元水压特性的过水系统模型,采用基于改进Suter变换-BP神经网络的水泵水轮机插值求解机制保证机组转速在极端工况区(驼峰区和反"S"区)的准确求解;然后均衡考虑抽水蓄能机组水泵断电工况下转速上升率和全流道特定节点压力脉动值,提出涉及水力、机械复杂因素的多重约束条件;再将邻域搜索和混沌变异机制引入到改进引力搜索(IGSA)算法中,并对所建模型进行优化求解。仿真结果表明,该策略可为导叶关闭规律优化和水泵断电工况下机组安全稳定运行提供有效的技术指导。     

基于精细化模型的抽水蓄能机组低水头开机多目标优化

为提高抽水蓄能机组运行于水轮机工况时低水头开机的控制品质,提出了一种基于精细化模型的抽蓄机组低水头开机多目标优化策略。首先,充分考虑过水系统、水泵水轮机、液压执行机构等机构非线性,建立抽蓄机组调节系统精细化模型。在此基础上,针对机组转速上升时间和转速超调量双目标,引入多目标人工羊群算法(MOASA)对两段式导叶开启规律进行多目标优化,得到Pareto最优解集,并对优化结果进行仿真试验。仿真结果表明,提出的开机规律多目标优化策略能有效地抑制机组深入反"S"区域,优化结果可为抽蓄电站的安全稳定运行提供决策支持。     

基于时滞微分方程的过水系统描述及其水击计算方法

针对解析法和数值分析法均难以精确建立过水系统连续模型的问题,在水击基本方程组的基础上进行变形求解,分析并推导出基于时滞微分方程的过水系统描述理论。基于该理论建立复杂过水系统的时滞微分方程组,研究了其离散求解方法并证明了解的存在性和唯一性。结合实际电站进行仿真计算并与特征线法的计算结果进行比较,验证了所提方法的适用性与优越性,为精确建立水力发电机组连续模型及研究控制策略奠定了基础。     

广州蓄能水电厂自适应微机调速器控制算法研究

针对抽水蓄能机组调速器控制工况繁多、控制逻辑较常规水火电机组复杂的问题,以广州蓄能水电厂# 4蓄能机组调速器为倒,介绍了发电与抽水工况下蓄能机组调速器的控制逻辑、相关算法及监控系统与调速器配合完成机组的有功控制过程,可供其他抽水蓄能电厂控制调速器参考.     

基于抽水蓄能的新型电力系统惯量优化控制方法

针对大规模新能源接入下导致新型电力系统惯性水平较低的问题,为满足电网准确、安全、快速的调频需求,文章提出了一种含抽水蓄能的新型电力系统惯性增强分布式控制方法。首先,研究电力系统发生暂态情况下抽水蓄能的转动惯量调节能力以及机组响应能力,从水力系统方向出发分析抽水蓄能调频能力,得到抽水蓄能的有功-频率特性;然后,采用频率变化率分别量化频率惯性,提出一种具有约束变化率的新型电力系统惯量完全分布式优化控制方法,可以在提高电网惯性的同时解决控制系统一致性问题;最后,以改进的IEEE34节点电力系统进行算例仿真,仿真结果表明,抽水蓄能机组能够改善电网频率和电压特性,并验证了所提控制方法的有效性。     

基于多回路理论的交流励磁电机转子绕组内部故障仿真与实验研究

交流励磁电机正逐步应用于变速抽水蓄能机组.与和常规水电机组相比,抽水蓄能机组由于转速高且启停频繁,它的转子绕组振动更剧烈,也更容易发生磨损并导致内部故障,因而需要研究针对变速抽水蓄能机组转子 绕组内部故障的主保护方案.本文研究交流励磁电机的转子绕组内部故障时采用多回路理论,首先将多回路建模法应用于交流励磁电机并编写程序以进行暂态故障仿真;然后在特制的交流励磁样机上进行不同工况下,转子绕组内部不同短路类型的故障实验,验证仿真计算的正确性.为了制定针对性强的主保护方案,本文进一步分析交流励磁电机转子绕组内部故障时的物理机理和电气特征,并据此提出监测定子分支环流的新型保护方案.     

基于Multi-Agent遗传算法风电-抽水蓄能联合优化运行

文章以经济和环境的综合效益最大化为目标,建立风电-抽水蓄能联合优化运行模型,考虑抽水蓄能机组和火电机组的各种运行限制,研究不同权重因子下电网效益、风电利用率和机组的出力情况,并研究了求解所建立优化模型的多Agent遗传算法,通过算例仿真验证所建模型及方法的有效性和实用性。结果表明风电场与抽水蓄能电站配合,可以降低风电对电网的影响,提高电网消纳风电的能力,还能够对火电厂机组功率起到平滑作用。     

某250MW抽水蓄能机组计算机监控系统控制流程及优化

鉴于抽水蓄能机组运行工况多,机组启停及工况转换频繁,控制流程相对复杂,对某250 MW抽水蓄能机组计算机监控系统顺序控制及工况转换流程进行梳理分析,并针对整组启动试运行期间出现的问题,对机组控制流程进行修改优化,结果可为新建抽水蓄能机组控制流程的设计或已投运机组控制流程的优化改造提供参考。     

等效焓降扩展算法的比较和联合应用

等效焓降法用于分析热力系统、计算热经济性指标时,十分简便、迅速,而且运算结果准确,所以应用也很广泛。面对热力系统中不同的问题和要求,我国学者在等效焓降法的基础上,提出了很多不同的改进算法。与等效焓降法相比,它们在具体问题和要求上更有针对性。对其中的部分算法进行分析和比较,并得出一个改进的等效抽汽法的计算模型,最后给出一个运用这个方法的算例。     

Equivalent circuit components of nickel-cadmium battery at different states of charge

Equations that describe the voltage variations with time of a rechargeable battery during charging and discharging were used to determine the component values of the equivalent circuit of nickel-cadmium batteries under different states of charge (SOC). The equivalent circuit of the battery was described as an ideal voltage source in series with a resistor and the parallel combination of a resistor and a capacitor. The battery model used different values of resistance and capacitance, in the parallel combination, during the different phases of the discharge-rest-charge-rest sequence. The results show that the series resistance is approximately constant with variations in the SOC while the resistor in the parallel RC circuit increases as the SOC decreases. For the discharge and charge phases the capacitor value increased and decreased, respectively, as the SOC decreased. The value of the resistor or capacitor in the parallel RC circuit is an indicator of the battery SOC.     

RC equivalent circuit model of lumped parameters for lithium ion batteries in electric vehicles

本项目以纯电动汽车锂离子动力电池集总参数RC等效电路模型为研究对象,在传统模型基础上,考虑了电池的极化效应特性和迟滞电压特性,创建一种新的锂离子动力电池动态等效电路模型;基于实验测试,对该模型参数进行了辨识,并通过实验分析验证,该模型的估算误差为2%,比传统一阶及二阶模型准确,比三阶RC模型简单。     

Equivalent circuit components of nickel-metal hydride battery at different states of charge

Equations that describe the voltage variations with time of rechargeable batteries during charging and discharging were used to determine the component values of the equivalent circuit of nickel-metal hydride batteries under different states of charge (SOC). The equivalent circuit of the battery was described as an ideal voltage source in series with a resistor and the parallel combination of a resistor and a capacitor. The battery model used different values of resistance and capacitance, in the parallel combination, during the different phases of the discharge-rest-charge-rest sequence. The results show that the resistances in the equivalent circuit are approximately constant with variations in the SOC. For the discharge and charge phases the capacitor value increased and decreased, respectively, as the SOC decreased. The value of the capacitor in the parallel RC circuit is an indicator of the battery SOC.     

电压注入式移相器建模研究

根据电压注入式移相器电路结构,基于变压器的基本原理推导得到了其稳态的三序等值电路。结合一个含电压注入式移相器的单机无穷大系统,对得到的等值电路进行了仿真验证,结果证实了所得等值电路的正确性。     

太阳电池内部电阻对其输出特性影响的仿真

通过对太阳电池的等效电路进行分析,建立了太阳电池的计算机仿真模型,定量地模拟了在一定光照下太阳电池内部的等效并联电阻及串联电阻对其伏安特性、开路电压、短路电流及填充因子的影响的程度。仿真结果表明：等效并联电阻产生的漏电流会影响太阳电池的反向特性和正向小偏压特性,且并联电阻影响其开路电压,但对短路电流基本没有影响；等效串联电阻会影响太阳电池的正向伏安特性和短路电流,而对开路电压没有影响；另外,并联电阻的减小和串联电阻的增大都会使太阳电池的填充因子和光电转换效率降低。仿真结果与实际测量的数据取得了相一致的结论。     

Equivalent circuit representation of a vortex-induced vibration-based energy harvester using a semi-empirical lumped parameter approach

Small-scale wind energy harvesting from vortex-induced vibrations (VIV) has been introduced in recent years as a renewable power source for microelectronics and wireless sensors. Previous studies have focused on modeling and optimizing the VIV-based piezoelectric energy harvester (VIVPEH) structures and simplified the complicated interface circuits as pure resistors with an alternating current (AC) output. In practice, an AC output is required to be transformed into a direct current (DC) followed by further regulations before being used for real applications. Incorporating the rectification and regulation, traditional theoretical and numerical models will become extremely cumbersome and even impossible. To address this issue, this work proposes an equivalent circuit model (ECM) for a typical VIVPEH. The Scanlan-Ehsan aerodynamic force model is employed to describe the fluid-structure interaction. Wind tunnel experiments are carried out to validate the derived model. The performances of the VIVPEH with AC and DC interface circuits are subsequently analyzed and compared to understand the influences of these circuits on the operational wind speed bandwidth, power output, vibration amplitude, and electrical damping.     

Three order state space modeling of proton exchange membrane fuel cell with energy function definition

The fuel cell is a complex system which is the centre of a lot of multidisciplinary research activities since it involves intricate application of various fields of study. The operation of a fuel cell depends on a wide range of parameters. The effect of one cannot be studied in isolation without disturbing the system which makes it very difficult to comprehend, analyze and predict various phenomena occurring in the fuel cell. In the current work, we present an equivalent electrical circuit of the pneumatics and fluidics in a fuel cell stack. The proposed model is based on the physical phenomena occurring inside fuel cell stack where we define the fluidic-electrical and pneumatic-electrical analogy. The effect of variation in temperature and relative humidity on the cell are considered in this model. The proposed model, according to the considered hypothesis, is a simple three order state space model which is suitable for the control purpose where a desired control structure can be formulated for high-end applications of the fuel cell as a subpart of a larger system, for instance, in hybrid propulsion of vehicles coupled with batteries and supercapacitors. Another key point of our work is the definition of the natural fuel cell stack energy function. The circuit analysis equations are presented and the simulated model is validated using the experimental data obtained using the fuel cell test bench available in Fuel Cell Laboratory, France.     

基于等价煤耗法的热电联产机组热经济性分析

热电联产机组热经济性代表了热电厂能量利用水平、热功转换技术的先进水平和运行的经济水平,因而准确地分析热电联产机组热经济性显得尤为重要.等价煤耗法是把电厂实际发电效益和供热效益通过热、电等价转换,得到等价发电量,进而得到等价煤耗率.结合300 MW机组,首先分别用热量法、实际焓降法和等价煤耗法对热电联产机组煤耗率进行计算,并通过分析比较,证明了等价煤耗法在评价热电联产机组方面的可行性和准确性;其次比较了同一热电联产机组在供热期和非供热期的煤耗率——供热期煤耗率比非供热期煤耗率低,从而证明了热电联产机组在节能方面优于纯凝机组.     

Modelling of Transduction Heaters Using Transformer Equivalent Circuit and Finite Element Analysis

This paper presents the modelling of transduction heaters using the TEC （transformer equivalent circuit） model and FEA （finite element analysis）. Each model was used to simulate a set oftransduction heating experiments and the results compared. Analysis of the TEC calculated results suggested modification of three parameters： the secondary resistance, the core tube eddy current resistance and the core tube magnetizing reactance. The improved TEC model was then used to design, build and test a 6 kW transduction heater. The measured results are compared with calculated results from the TEC and FEA models. The TEC model accurately predicts the performance of the heater.