Hamiltonian realization of power system dynamic models and its applications

Power system is a typical energy system. Because Hamiltonian approaches are closely related to the energy of the physical system, they have been widely researched in recent years. The realization of the Hamiltonian structure of the nonlinear dynamic system is the basis for the application of the Hamiltonian methods. However, there have been no systematically investigations on the Hamiltonian realization for different power system dynamic models so far. This paper researches the Hamiltonian realization in power systems dynamics. Starting from the widely used power system dynamic models, the paper reveals the intrinsic Hamiltonian structure of the nonlinear power system dynamics and also proposes approaches to formulate the power system Hamiltonian structure. Furthermore, this paper shows the application of the Hamiltonian structure of the power system dynamics to design non-smooth controller considering the nonlinear ceiling effects from the real physical limits. The general procedure to design controllers via the Hamiltonian structure is also summarized in the paper. The controller design based on the Hamiltonian structure is a completely nonlinear method and there is no linearization during the controller design process. Thus, the nonlinear characteristics of the dynamic system are completely kept and fully utilized. Supported in part by the National Natural Science Foundation of China (Grant Nos. 50707009 and 50525721), in part by Program for Changjiang Scholars and Innovative Research Team in University under IRT0515 and in part by Ministry of Education of China (Grant No. 20070079014)     

关于解决供电配电所问题的协调控制战略研究

提出了在主变压器事故、工作计划、过负荷、预防过负荷等问题在供电配电所出现的时候,以电力SCADA系统和配电SCADA的协作控制战略(CCT:Coord ination Control Strategy)为基础,研究运用负荷切换战略来消除事故波及效果的同时提高配电所运营安全性的方法.协调控制战略分为2阶段:第1阶段,通过利用母线重构解决方案(DSBRES:D istribution Substation Bus ReconfigurationExpert System)得出供电配电所的母线重构战略;第2阶段,根据从第1阶段得出的资料和配电系统重构解决方案(DSFRES:D istribution Systsem FeederReconfiguration Expert System)而得出配电系统线路重构.最后,给出了能表示供电、配电所和配电系统特性的代表性供电配电所模式和配电系统的模式.     

风电场SCADA系统的数据传输技术

为了使设备与设备之间以及设备与电网之间有良好的数据传输能力,根据风电场上、下位机之间数据传输的特点,对适合于风电场SCADA系统的数据传输方式进行了分析研究.阐述了专门面向风电场监控通信的IEC 61400 25标准的体系结构和适用范围,其中重点阐述了风电场监控通信的信息模型和信息交换模型及其建模方法.研究表明,风电场SCADA系统的数据传输必须满足远距离通信能力强、实时性洽可靠性高的要求,才能保证对风电场的统一管理、运营及维护.     

BITBUS监控系统在厂用变电站中的应用

本文阐述了BITBUS分布式微机监控系统的结构,及其在厂用变电站中的应用,这种系统具有性能优异、价格低廉等特点,已有一套用于兰炼厂的供电系统中。     

On engineering implementation of the digital power system

The narrow definition of the digital power system (DPS) is proposed. The architecture, features and key contents of the DPS are presented, which include intelligent dispatching system, hybrid automatic control system and data sharing platform. The successful construction of the DPS can greatly improve the performances of power system operating and dispatching, which mainly reflect a fundamental increase of the ability of avoiding catastrophes resulting from blackouts of power supply, a significant improvement of economic efficiency of power system operation, and an improvement of decision efficiency of power system developing. The DPS describes a vision of the development of power system and the way to achieve this vision. At the same time, the paper also proposes the principles of the design and implementation of the DPS. Supported by the National Natural Science Foundation of China (Grant Nos. 50595411 and 50377018) and the Major State Basic Research Development Program (973 Program) (Grant No. 2004CB217903)     

Novel approach for evaluation of service reliability for electricity customers

Understanding reliability value for electricity customer is important to market-based reliability management. This paper proposes a novel approach to evaluate the reliability for electricity customers by using indifference curve between economic compensation for power interruption and service reliability of electricity. Indifference curve is formed by calculating different planning schemes of network expansion for different reliability requirements of customers, which reveals the information about economic values for different reliability levels for electricity customers, so that the reliability based on market supply demand mechanism can be established and economic signals can be provided for reliability management and enhancement. Supported by the Program for New Century Excellent Talents in University (Grant No. NCET-07-0484), the National Natural Science Foundation of China (Grant No. 50777031) and the Fok Ying-Tong Education Foundation (Grant No. 104020)     

A transient energy function for power systems including the induction motor model

A construction method for power system transient energy function is studied in the paper, which is simple and universal, and can unify the forms of some current energy functions. A transient energy function including the induction motor model is derived using the method. The unintegrable term is dealt with to get an approximate energy function. Simulations in a 3-bus system and in the WSCC 4-generator system verify the validity of the proposed energy function. The function can be applied to direct transient stability analysis of multi-machine large power systems and provides a tool for analysis of the interaction between the generator angle stability and the load voltage stability. Recommended by Prof. LU Qiang, Member of Editorial Committee of Science in China, Series E: Technological Sciences Supported by the Special Fund of the National Priority Basic Research of China (Grant No. 2004CB217904) and the National Natural Science Foundation of China (Grant No. 50323002)     

基于分层的在线生成电网调度操作票专家系统

通过对电网结构和电网调度操作票的建立机制进行分析，基于分层结构的规则设计，利用应用数据库与面向对象的编程（OOP）技术设计了电网调度操作票专家系统，采用多智能体系统（MAS）实现与SCADA系统实时共享数据。文章给出该方法的设计思想、应用和设计系统的主体框架。     

电网故障定位数据的WINSOCK实时通讯

介绍了实时数据通讯的Ｓｏｃｋｅｔ通讯方式,讨论了这种通讯方式的基本原理,系统的实现,以及采用该方法实现ＳＣＡＤＡ系统与高层软件系统之间数据通讯的优点。     

“变电站变压器经济运行检测系统”的应用

变电站变压器按经济运行是降低电力系统网损和节省变压器能损的重要措施,应用“变电站变压器经济运行检测系统”,通过对变电站负荷变化时的综合功率损耗的动态计算和分析比较,从而鉴别变电站是否处于经济运行方式,并使变电站实现按经济运行方式运行,对降低变电站内变压器损耗,节省电能,缓解我国电力紧张的状况是具有现实意义．     

变电站综合自动化系统问题浅析

采用变电站综合自动化技术是电网发展的趋势,但同样也带来了一些问题。基于运行经验,介绍了变电站综合自动化系统,从技术、管理、人员素质等方面阐述了当前变电站综合自动化系统实际应用中存在的若干问题．并针对这些问题提出了一些建议。     

基于IEC62351的变电站自动化系统通信安全的研究

随着信息技术的发展,电力工业的信息安全已成为影响电力系统稳定运行的重要问题,IEC62351标准的提出对变电站通信系统与网络安全提供了保障,通过对IEC 62351标准和安全访问的分析,提出建立安全标准典型应用的安全模型,并设计出拥有身份认证、机密性和完整性的安全模型。安全模型的设计紧跟IEC 62351在数据和通信安全中的要求,并且遵从电力系统自动化现行的信息安全机制。通过该模型应用实例的描述和分析,证明能满足网络环境下变电站IED的安全访问和控制。     

Development of multidimensional sequence operation theory with applications to risk evaluation in power system generation scheduling

Sequence operation theory (SOT) is a powerful tool for solving complex probabilistic problems in power system. However, the basic single dimension SOT cannot satisfy the requirement of multi-state and multi-attribute analysis, which is often the case in actual power system practice. To address this problem, multidimensional sequence operation theory (MSOT) is developed. On the basis of previous research, this paper first categorizes the situations by the number of state variables and the number of attribute values, and defines the multidimensional sequence for single state variable and multiple attribute values, as well as the multidimensional sequence for multiple state variables and multiple attribute values. Corresponding to those definitions, four types of operations between two discrete multidimensional sequences are derived respectively. Therefore, the sequence is extended from single dimensional to multidimensional, establishing an integrated theory of multidimensional sequence operation. In particular, the basic single dimension SOT can be viewed as a special case of MSOT with only one state variable and one attribute value. Finally, the paper demonstrates the effectiveness of MSOT through an example of risk evaluation in power system generation scheduling. Supported by the National Natural Science Foundation of China (Grant No. 50777031), Program for New Century Excellent Talents in University (Grant No. NCET-07-0484) and the Fok Ying-Tong Education Foundation (Grant No. 104020)     

可扩展型微电网SCADA系统关键技术

为了突破传统的微电网SCADA系统结构封闭、难以满足二次开发需求的局限性,提出可扩展的微电网SCADA系统模型,满足多种新能源元件的监测和计算需要,快速工程化,同时支持多种微网运行控制策略及扩展.系统基于面向服务架构（SOA）进行业务功能的封装与扩展,实现一体化模型维护方案,并且提供面向设备与模型的智能化计算与控制方法.针对传统微电网SCADA业务功能,应用基于SOA技术的重构,建立具备良好适应性与多重扩展性的微电网SCADA平台,提升SCADA技术的互联性、灵活性与多样性,应用于不同形态的微电网.通过南都储能电站案例,展现系统开放互联的应用效果.     

Dynamic security risk assessment and optimization of power transmission system

The paper presents a practical dynamic security region (PDSR) based dynamic security risk assessment and optimization model for power transmission system. The cost of comprehensive security control and the influence of uncertainties of power injections are considered in the model of dynamic security risk assessment. The transient stability constraints and uncertainties of power injections can be considered easily by PDSR in form of hyper-box. A method to define and classify contingency set is presented, and a risk control optimization model is given which takes total dynamic insecurity risk as the objective function for a dominant contingency set. An optimal solution of dynamic insecurity risk is obtained by optimizing preventive and emergency control cost and contingency set decomposition. The effectiveness of this model has been proved by test results on the New England 10-genarator 39-bus system. Supported by the key research of the National Natural Science Foundation of China (Grant No. 50595413) and The National Basic Research Program of China (973 Program) (Grant No. 2004CB217904)     

Relaxor behavior and electrical properties of high dielectric constant materials

Several typical high dielectric constant materials are reviewed to study the electrical properties and relaxation mechanism. It is found that a Lorenz-type law can be used to describe the dielectric permittivity of either the normal ferroelectrics with or without diffuse phase transitions (DPT) or the typical ferroelectric relaxors. The ferroelectric DPT can be well described by just one fitting process using the Lorenz-type law, while the relaxor ferroelectric transition needs two independent fitting processes. The Lorenz-type law fails at the low temperature side of the dielectric maximum of a first-order ferroelectric phase transition. Above the transition temperature, the dielectric curves of all the studied materials can be well described by a Lorenz-type law. Supported by the National Natural Science Foundation of China (Grant No. 50672075), New Century Excellent Talents (Grant No. 05-087), Natural Science Foundation of Northwestern Polytechnical University (Grant No. 200703), Xi’an Science & Technology Foundation (Grant No. CXY08006) and 111 Project (Grant No. B08040)     

三维虚拟变电站数字可视化管理与监控系统

研究面向变电站营运管理的三维虚拟数字可视化系统,将三维虚拟和数字可视化技术与变电站现有系统与信息集成起来,包括PMIS系统、实时监控系统、实时视频监控系统、火灾报警系统、安全防护系统等,实现变电站各种信息的一体化多维展示,解决目前变电站各种系统以二维方式离散展示信息的缺陷,提高变电站的运行管理与监控水平.     

Design of a control system for a macro-micro dual-drive high acceleration high precision positioning stage for IC packaging

A macro-micro dual-drive positioning system showing good potential for high acceleration and high precision positioning required in IC packaging applications is devised in this paper. The dual-drive positioning stage uses a VCM (voice coil motor) driven macro positioning stage and a PZT piezo-electric driven micro positioning stage. The coupling characteristics of the system are analyzed to produce a control structure with a micro positioning stage that can dynamically compensate for the positioning error produced by the macro positioning stage. Models of the two positioning stages are described. The models cover both the mechanism and the actuator. For the macro positioning stage, friction characteristics are taken into account, and a controller with an LQG (linear-quadratic-Gaussian) control algorithm combining a feed-forward compensation algorithm is derived. A PID controller is used to control the micro positioning stage. Detailed designs are derived for the proposed approach, and the performance is validated by simulation. Supported by the National Natural Science Foundation of China (Grant No. 50705027), the National High Technology Research and Development Program of China (“863” Program) (Grant No. 2007AA04Z315) and Self-Planned Task of State Key Laboratory of Robotics and System (HIT) (Grant No. SKLRS200804B)     

某变电站遥控误出口原因分析与改进措施

针对陕西110kV沙坡变电站RTU发生的遥控误出口故障,通过现场设备检测和实验室故障再现等手段分析了产生故障的原因.发现I/O单元电源故障是导致误出口的直接原因,遥控过程通道的驱动电路设计也存在缺陷.提出遥控输出驱动电路的设计方案,避免电源电压波动造成误动;改造原装置的电源系统,设计出防电源异常导致遥控误出口的闭锁电路,防止电源故障造成遥控单元误出口.实验室验证和工程实施的结果表明,改造后的RTU不会再出现类似的故障.     

Acoustic properties of sintered FeCrAlY foams with open cells (II): Sound attenuation

Open-celled metal foams fabricated through metal sintering offers novel mechanical, thermal and acoustic properties. Previously, polymer foams were used as a means of absorbing acoustic energy. However, the structural applications of these foams are inherently limited. The metal sintering approach provides a cost-effective means for the mass-production of open-cell foams from a range of materials, including high-temperature steel alloys. The low Reynolds number fluid properties of sintered steel alloy (FeCrAlY) foams were investigated in a previous study. The static flow resistance of the foams was modeled based on a cylinder and a sphere arranged in a periodic lattice at general incidence to the flow, with the resulting predictions correlating well to measurements. The application of the flow resistance in an acoustic model is the primary focus of the present study. The predictions for the static flow resistance of the sintered foams are first used in a theoretical model to determine the characteristic impedances, as well as the propagation constants of the foams. Subsequently, the predicted acoustic performance of the foams is compared to experimental results. Finally, the design space for a simple acoustic absorber incorporating sintered foams is examined, with the effects of absorber size, foam selection, and foam spacing explored. Supported by the National Basic Research Program of China (Grant Nos. 2006CB601202, 2006CB601204), the National 111 Project of China (Grant No. B06024), US Office of Naval Research (Grant No. N000140210117), the National Natural Science Foundation of China (Grant Nos. 10572111, 10632060), and the National H-Tech Research and Development Program of China (Grant No. 2006AA03Z519)