区域市场中电力公司报价辅助决策系统设计

以华东区域电力市场为工程背景提出了一个电力公司报价辅助决策系统的整体技术方案,围绕系统功能、设计思想和软件构架进行了论述.通过分析当前市场环境,对现有研究进行了比较,提出了比较实用的核心算法,对各应用局限提出了相应的解决方案.对市场试运行阶段需求多变等问题,提出了系统与MATLAB工具箱整合等方案.     

Development of unbalanced load flow program for large power systems

The idea of unbalanced load flow calculation was proposed many years ago. At that time, however, the needs for such techniques was not urgent. Modern power system networks are comprised of long untransposed transmission lines. Therefore, for some kinds of analysis, it is now almost impossible to treat a system as though it were a symmetrical network. The aims of most previous studies were oriented to solve voltage/current imbalance in local or small systems, as local imbalance was a serious concern. This is still an important issue, but more recently needs have become concentrated on practical bulk power systems, since principal EHV lines are entirely untransposed. In this paper, the development of practical unbalanced load program and practical experience with it are reported. This program was developed for steady-state analysis of large-scale practical networks under many possible unbalanced conditions. The Newton-Raphson method in polar coordinates is used, since fast and moderate convergent characteristics are suitable for solving solutions. The program was applied to practical case studies. The models contain all of the 500-kV and most of the 275-kV overhead transmission lines in TEPCO. Since the density of the Jacobian matrix is higher than in single-phase load flows, the number of nonzero elements is extremely large. Convergent characteristics are excellent in all cases. The fear of numerical instability has been allayed.     

锅炉汽包瞬态温度场计算新方法

利用反推法求解锅炉启停及变负荷运行过程汽包温度场,建立数学模型,并将计算结果与理论计算结果相比较。结果表明,该方法计算准确度高,可以应用于实际工程。     

基于最小二乘支持向量机和自适应模拟退火算法的电磁场逆问题全局优化方法

分析了目前电磁场逆问题全局优化算法存在的收敛速度慢以及搜索时间长等问题的主要原因,并针对以上问题提出了基于最小二乘支持向量机和自适应模拟退火电磁场逆问题优化新算法,充分利用了自适应模拟退火算法中丢失的已搜索过点的信息,动态地建立和改进待求问题的数值模型,指导最优解的搜索过程,大大减少了求解电磁场正问题的求解次数,缩短了搜索到最优解的时间,通过仿真实验以及实际应用的对比,效果显著,提高了电磁场优化设计的实际应用能力。     

用于智能仪表温度测量的数值分析方法

温度传感器主要包括热电偶、热电阻.通常给出的热电偶的温度与热电势即t与E的转换关系及系数表[1],不能直接用于智能仪表中微处理器的温度运算与处理.本文提出了一种分段拟合多项式的数值分析方法,并使用C语言完成程序的编制及运行.此方法生成的热电偶的温度与热电势的反函数的多项式的阶数较低,适用于智能仪表中微处理器的温度计算及测量显示.实际温度测量验证了此数值分析方法的可行性和正确性.     

华东电网并网机组涉网保护相关标准及核查问题分析

随着电网和电源的快速发展,系统特性发生深刻变化,合理规范的并网机组涉网保护参数是保障电力系统安全稳定运行的重要因素。在指出涉网保护包含的具体内容后,结合华东电网实际,分析了标准相关条文的内涵,并针对频率异常保护、失磁保护等容易出现问题的环节提出了对应的标准执行意见。介绍了华东电网并网机组涉网保护专项核查工作依据的具体规范和实际工作方法,总结归纳了核查中出现的问题危害和解决方法,分享了典型问题核查案例。最后建议建立长效管理机制,保障相关核查工作持续滚动开展。     

“双碳”目标下我国碳捕集、利用与封存政策分析及建议

聚焦碳捕集、利用与封存(carbon capture, utilization and storage,CCUS)新兴低碳技术,介绍了近年来国外主要发达经济体的政策发展情况,另外着重从国家、地方政府层面入手对我国相关政策或规划进行了整理分析。过去10余年间,系列政策的适时发布有力促进了我国CCUS的布局与发展,技术目前总体处于工业示范阶段。然而,相较美国、欧盟等发达经济体,我国CCUS技术能力与项目规模仍有一定差距,并存在财税激励或补贴政策尚未出台、法律法规与标准体系建设缓慢、产业链布局不完善和国际合作话语权不强等主要不足。建议立足我国实际国情,在总结借鉴国外CCUS良好政策与实践经验的基础上,加快推动低成本、低能耗、安全可靠的CCUS关键技术研发与产业集群建设,深化国际合作,逐步建立产业发展主导优势,助力“双碳”目标实现。     

MMC-HVDC电网输电线路双极短路故障电流的实用计算

基于模块化多电平换流器的高压直流电网作为支撑高比例可再生能源接纳的有效手段,已经成为电网发展的重要方向。双极短路故障是输电线路发生的最严重故障,目前一般通过在s域内列写直流系统状态方程,然后再基于拉氏反变换求解故障电流,亟待提出短路电流的工程实用计算方法。为此,以张北柔性直流电网为研究对象,首先分析了输电线路双极短路的故障特性及耦合机理。在此基础上,将故障线路靠近阀侧的两端分别看作二端口,分析了故障电流与二端口两侧电压的关系。其次,基于正、负极线路二端口电压变化不大的思想,将环形直流电网简化为两端网络或开式网络,得到故障线路电流的实用计算方法,不再需要求解高阶的拉氏反变换而直接得到故障电流。最后,通过与电磁暂态仿真结果的对比,验证了实用计算方法的可行性与高效性。     

Optimization of multiobjective system reliability design using FLC controlled GA

A practical optimal reliability design of a system requiring high system reliability could be formulated as an appropriate mathematical programming model; however, in the real world, we should be concerned with some kinds of decision criteria. In particular, system reliability and construction cost are basically in conflict with each other, so that when taking both of them into consideration, the system reliability design model can be formulated as a bi‐objective mathematical programming model. In this research, we consider a bi‐criteria redundant system reliability design problem which is optimized by selecting and assigning system components among different valuable candidates for constructing a series‐parallel redundant system. Such a problem is formulated as a bi‐criteria nonlinear integer programming (bi‐nIP) model. In the past decade, several researchers have developed many heuristic algorithms including genetic algorithms (GAs) for solving multi‐criteria system reliability optimization problems and obtained acceptable and satisfactory results. Unfortunately, the Pareto solutions obtained by solving a multi‐objective optimization problem using a GA cannot guarantee its quality, and the number of Pareto solutions obtained is sometimes small. In order to overcome such problems, we propose a hybrid genetic algorithm combined with a Fuzzy Logic Controller (FLC) and a local search technique to obtain as many Pareto solutions and as good as possible. The efficiency of the proposed method is demonstrated through comparative numerical experiments. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(3): 72–80, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20319     

华东电力市场月度双向竞价模式

介绍了华东电力市场月度双向竞价模式,建立了相应的数学模型,根据实际算例以及华东电力市场第1次模拟运营的结果分析了这一交易方式的特点.市场交易情况表明,月度双向竞价模式是一种既能充分发挥市场优化资源配置作用、创造良好社会效益,又极为简明、易于实施的电力市场交易方式.并探讨了出现月度电量竞价这一具有中国特色的电力市场结构设计的背景,分析了月前市场的意义,讨论了电量竞价的合理性,指出在供求关系较为紧张的电力市场中,长周期、大批量的月度电能交易有利于电力市场的长期稳定运行.此外,针对华东电力市场月度竞价模式设计中遇到的一些实际问题,包括月度竞价的报价方式、月度竞价结果对应的契约关系等,提出了解决办法.     

基于蚁群最优的配电网网架规划方法

配电网规划问题是一个复杂的组合优化问题。蚁群算法是用于解决组合优化问题的一种高效的随机化内启发式全局搜索技术,能有效地求解大规模组合优化问题。文中结合单阶段配电网规划问题的特点,应用蚁群算法来解决配电网规划问题,建立了相应的数学模型,并给出求解算法。算例的计算结果表明了这种方法是可行、有效的。     

Systematic construction of vector solitons

We present a simple but powerful method for constructing multisolitons; of the integrable Manakov (coupled nonlinear Schrodinger) equation. Our method is essentially equivalent to the inverse scattering method (ISM) with the full strength generality but without the mathematical rigor of the ISM. This makes our method appropriate for practical purposes. A closed form of matrix determinant for the N-soliton solution in a nonvanishing background is found in this way. We work out explicitly the two dark vector soliton and the three bright vector soliton cases and demonstrate their novel behaviors     

The Decomposition Method in Issues of Researching Electric-Power Systems with Dry Friction

Electrical engines are widespread in all areas of industry and technology. Electrical actuators are widely used as an actuating motor regulating the interconnected controls of different machines. Increased demands for precision in interconnected controls make it very important to consider dry friction in the executive mechanism. The consideration of dry friction in a mathematical model of an automatic system considerably complicates its analysis. In all known practical cases of research into such issues, the research is carried out by means of computing or analytically, but using a considerably simplified model of the dry-friction law. This simplified presentation does not allow one to uncover and understand the true (or apparent) reasons for loss of stability in a system accompanied by friction self-oscillations of different kinds (periodical, chaotic etc.). The decomposition method of parameter space presented in the current work allows investigation of nonautonomous nonlinear multivariable systems via basic subsystems (both linear and nonlinear) that have a lower-order state space and are amenable to strict analysis.     

Study on mathematical model for VHF partial discharge of typical insulated defects in GIS

Very high frequency (VHF) measurement is a valid technique for partial discharge (PD) detection, and PD mathematical models are very important to study PD denoising and waveshape pattern recognition etc. However, these mathematical models based on the traditional PD measurement have been established according to RC or LCR resistance detection so that they are not suitable for VHF measurements. PD signals are detected based on four typical physical models of defects in gas insulated substation (GIS) using VHF method. The VHF PD mathematical models are established, and the principles and methods of establishment are summarized. Furthermore, the parameters of the mathematical models are given and the validity of PD mathematical model is proved by fitting error, power spectrum and time-frequency analysis. Results show that the VHF PD mathematical models can facilitate theoretical simulation of different insulated defects by using the values of given parameters. In the end, applications of the VHF PD mathematical models and complex wavelet transform for extracting the relevant signals from a white noise background are illustrated     

数学建模活动的开展与探索

数学建模是用数学知识分析、解决实际问题的过程,从数学建模示范、数学建模训练、数学建模能力的评价、数学建模辅助活动等四个方面介绍了教学中数学建模活动的开展。通过数学建模活动,加深了学生对数学知识与方法的理解和掌握,激发了学生学习数学的兴趣与爱好,提高了学生应用数学知识解决实际问题的能力。     

新千年前十年铅酸蓄电池的发展方向

回顾了铅酸蓄电池(LAB)在所有电化学电源(EPS)中的地位以及电池市场对铅酸蓄电池新的要求。阀控式铅酸蓄电池(VRLAB)是需要最少维护的电池,重点讨论了已解决或正在解决的VRLA电池的基础性能,以满足未来10年电池市场对电化学电源的要求。在对那些对VRLAB性能有重要作用的过程进行详细论述之后,论述了研制铅酸蓄电池一般要考虑的问题。特别要注意附加反应对封闭氧气循环的利用率和热问题的影响。最后讨论了一些新型LAB设计,这些电池在未来10年的电池市场中将占有很重要的位置。     

智能变电站电压并列装置的改进

指出电压并列装置是实现变电站内电压回路切换的重要装置。阐述了在现有大多数智能变电站建设中,电压并列装置仍然沿用了传统变电站的设计方法,即通过控制把手进行手动切换,这样不仅不具备远方操作的功能,而且在与智能回路的配合使用中出现了一些明显的逻辑缺陷。提出了一种电压并列装置逻辑问题的解决办法,并提出了适合用于智能变电站智能电压并列装置的设计思路。     

Minority Women in Engineering Schools

A decade ago the general public had a very nebulous concept of an engineer. It ranged from one who drove a train to one who collected garbage-a sanitation engineer. Those who were more knowledgeable about engineers still looked upon them as people doing a highly specialized job but who had little other talent. Although engineering has gained prestige and made fantastic contributions to technology during the last decade, there still exist some very great inequities. One of the most significant of these is engineering education as it relates to the black female and to other minority groups studying both for an undergraduate and a graduate degree in some field of engineering.     

一种输电线路特殊接线方式对线路距离保护影响研究

建立了同杆双回输电线路串接入单回输电线路的数学模型,分析了常用的线路距离保护受到的影响。分析结果表明:距离保护会受到一定程度的影响,其影响程度与系统方式、线路参数以及故障点位置有关,定值整定时需对距离保护灵敏度进行校核。编制了全线故障点扫描软件,图形化展示灵敏度情况,供定值整定人员参考。针对距离保护灵敏度问题提出了两种解决方案。根据实际工程参数建立RTDS仿真模型并接入了实际使用线路保护装置,进行了验证性测试。测试表明,超范围整定的距离Ⅱ段或者纵联距离灵敏度整定不合适时,确有可能出现保护拒动的情况。最后再次强调了应尽量从一次系统规划上避免出现这种特殊的接线方式。     

电力系统稳定器投入引起机端功率振荡的研究分析

电力系统稳定器（（power system stabilizer,PSS）是解决电力系统低频振荡有效而又经济的重要手段,有利于提高电力系统的动态稳定性,但是技术的复杂和设备本身的参数设置可能带来系统运行安全可靠性问题,为此,介绍某励磁系统在 PSS投入时引起发电机机端功率振荡事故的具体经过,根据 PSS实际应用的技术模型,分析导致系统功率振荡的具体细节,提出相应的解决方法,避免相似事件再次发生,减少经济损失和提高系统安全性。