Assessing power system security. A framework and a multi model approach

This paper presents a methodological framework using a multi model approach to assess power system security. System security is viewed here as a multidimensional systemic property of the entire energy system. The paper shows that the different dimensions of a secure energy system are correlated, and hence their behaviour cannot be explained solely by an understanding of the individual dimensions or by system elements in isolation. The implication of this is that a proper assessment of the security of a power system requires a combination of different techno-economic models. The paper develops a comprehensive multi-model approach for investigating energy security issues within power systems, and applies it to a case study focussing on the Italian power sector. The core research activity involves using an energy systems model of Italy (MONET) to build a dedicated power systems model (PLEXOS_IT) and then undertaking a soft-linking exercise between the two models. The purpose is to use PLEXOS_IT to investigate the system adequacy of the power system results produced by MONET for future possible energy system scenarios.     

组合电力系统概率安全性与概率充裕性综合评估

概率安全性与概率充裕性评估是组合电力系统可靠性研究的两个方面。由于建模的复杂性和巨大的计算量,二者在过去一直是分开研究的,这样造成所得的两类指标缺乏可比性和统一性。本文将二者协调统一在同一框架内,提出了一整套综合评估风险指标,建立了完整的基于序贯蒙特卡罗仿真的发输电合成系统可靠性综合评估新体系。算法结合自组织映射网络和合并相同系统状态加速计算技术,并在安全性评估中考虑了不对称故障等多种故障模式对可靠性指标的影响。对IEEE标准可靠性测试系统进行计算分析,结果表明所提算法可行有效。     

基于动态安全域的电力系统安全概率评估模型

针对电力系统安全性问题特性,提出一种基于动态安全域的安全概率评估模型。模型核心是不安全概率指标,并通过该指标来表征各电力元件以及整个电力系统的安全性状况。概率方法的引入,使得模型不仅计及系统中各种主要的不确定性因素,而且对系统的安全状况进行了定量的描述。动态安全域理论大大降低了安全概率评估的计算量,使得该模型具有实用性。评估结果可以用于指导运行人员在安全控制中制定正确的决策。用新英格兰10机39节点系统(New England 10-generator 39-bussystem)对该模型做了验证。     

A multiagent approach to power system normal operation

Recently, the electric utility industry worldwide has been facing pressure to be deregulated or restructured in order to increase its efficiency, to reduce operational cost, or to give consumers more alternatives. For this aspect, a great deal more research is needed to achieve a better, intelligent knowledge process. The present centralized system for power system control, operation, and planning must be remodeled to cope with these situations. With the promotion for the deregulation of the electric power system, the definition of the objective function for the optimization problem such as outage work operation for electric power systems is becoming critical. Currently, agents are an intense focus in many subfields of computer science and artificial intelligence. Agents are being used in an increasingly wide variety of applications. In this paper, we developed a power system normal operation application by multiagent architecture. Our multiagent system consists of several facilitator agents, equipment agents, and switch‐box agents. Facilitator agent acts as a manager for negotiation process between agents. Equipment agent corresponds to the element of the electric power system, such as bus, transformer, and transmission line, while switch‐box agent is the pseudo object which consists of neighboring current breakers and disconnecting switches. The proposed system realizes the appropriate switching operations by interacting with corresponding agents. The proposed approach is applied to a simple network, and the results show that the proposed multiagent system is an efficient decentralized approach for solving power system normal operations. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 26–33, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10227     

基于安全网关的电力二次系统安全防护

分析了电力二次系统安全区Ⅰ和安全区Ⅱ之间的主要业务系统的数据交换,以及存在的安全问题;设计了基于混沌序列算法的加密解密模块,模块的密钥基于时间同步自动产生;设计了基于主动防御和被动防御相结合的安全网关,将防火墙、加密、入侵检测和蜜网结合在一起。实验证明设计的安全网关达到了预期的效果,可以满足实时性的要求。     

A tableau approach to power system analysis and design

The tableau formulation of electronic circuit equations has been shown to be an efficient and useful formulation for circuit optimization. In this paper a tableau based formulation of the static power-flow equations for a power system is presented. Because of the explicit appearance of all quantities of interest the tableau formulation allows the general statement, and solution, of a variety of power system optimization and design problems without the need to resort to restrictive assumptions.     

A frequency and duration approach for generation reliabilityevaluation using the method of stages

A frequency and duration approach for generation reliability evaluation using the method of stages is presented. Two separate expressions are provided, one for the loss of load expectation (LOLE) and the other for the loss of load frequency (LOLF). Explicit relationships for determining the parameters of these expressions from the generation system data are derived. Several studies to illustrate the accuracy and efficiency of the proposed approach are also reported     

ANN based integrated security assessment of power system using parallel computing

This paper presents the application of cascade neural network (CANN) based approach for integrated security (voltage and line flow security) assessment. The developed cascade neural network is a combination of one screening module and two ranking modules, which are Levenberg–Marquardt Algorithm based neural networks (LMANNs). All the single line outage contingency cases are applied to the screening module, which is 3-layered feed-forward ANN having two outputs. The screening module is trained to classify them either in critical contingency class or in non-critical contingency class from the viewpoint of voltage/line loading. The screened critical contingencies are passed to the corresponding ranking modules, which are developed simultaneously by using parallel computing. Parallel computing deals with the development of programs where multiple concurrent processes cooperate in the fulfillment of a common task. For contingency screening and ranking, two performance indices: one based on voltage security of power system (VPI) and other based on line flow (MWPI) are used. Effectiveness of the proposed cascade neural network based approach has been demonstrated by applying it for contingency selection and ranking at different loading conditions for IEEE 30-bus and a practical 75-bus Indian system. The results obtained clearly indicate the superiority of the proposed approach in terms of speedup in training time of neural networks as compared to the case when the two ranking neural networks were developed sequentially to estimate VPI and MWPI.     

一种SSE-CMM的电力通信系统风险度算法分析

结合电力通信网的现状,提出了一种基于系统安全工程能力成熟模型（SSE-CMM）的电力通信系统安全评估的方法.文章首先简要介绍了SSE-CMM模型,阐述了根据SSE-CMM对电力通信系统进行安全性能评估的步骤和方法,并结合模糊综合评判法对电力通信系统的风险度进行计算.计算结果显示,文中采用的方法具有指导性、实用性和可操作性.     

Reactive power market development considering power system security

In the new open access environment, in pursuit of profit, power producers tend to operate closer to the security boundaries and consequently, the voltage instability, which is caused by insufficient reactive power support, threats system security and reliability. This paper presents a day-ahead reactive power market based on uniform auction price scheme considering voltage security. First, expected payment function (EPF), identified earlier in the literature to construct a bidding framework for synchronous generators, is modified. Then, the modified EPF is used as the objective function of optimal power flow problem to clear reactive power market. Finally, the OPF, including overload, voltage drop and voltage stability margin in its constraints, is solved by binary coded genetic algorithm. The validity of the proposed reactive power market is studied based on the IEEE 24-bus reliability test system.     

A comprehensive approach for adequacy and security evaluation ofbulk power systems

A new approach is described for assessing the adequacy and security of bulk power systems. The method takes into account generation and transmission failures, load variation, generation economic dispatch, security limits, maintenance schedules, the control actions implemented in emergencies. and the impact of different operating schemes. Reliability indices for generation adequacy, transmission adequacy, and system security are defined. The proposed method is demonstrated by application to the IEEE Reliability Test System (RTS)     

A novel simplified approach to complexity of power system components including nonlinear controllers based model reduction

Based on differential algebraic (DA) subsystem models of power system components including the nonlinear controllers, which are called component structural complex models, this paper presents a model reduction method (MRM). For the dynamic differential equations, based on the property that the nonlinearity of the controller compensates that of the component completely (or partially), the presented method uses the linear dynamic equations to describe the compensated dynamics. For the algebraic connection equations, the new defined state variables are used to substitute the original state variables for keeping the connection relation invariable. By selecting generators and static var compensators (SVC) as examples, the paper presents the basic procedure of the proposed reduction method for power system component complex models in detail. The numerical simulation indicates that the derived simplified models matches the original one very well in both dynamic response behaviors and the connection relation with the external system.     

New approach to power system stabilizer design

A generalized method for the design of excitation control or a power system stabilizer (PSS) based on complex frequency is described. The method selects PSS parameters such that exact assignment of eigenvalues associated with the mechanical modes of oscillation to desired locations is achieved. Numerical examples are used to illustrate the concepts of the proposed new technique.     

基于数据挖掘的电力信息系统网络安全态势评估

为了解决当前电力信息系统网络安全态势评估建模过程存在的一些难题,提出基于数据挖掘的电力信息系统网络安全态势评估模型。首先对电力信息系统网络安全态势评估现状进行分析,构建电力信息系统网络安全态势评估指标体系,然后采用灰色关分析法确定电力信息系统网络安全态势评估指标体系的权重值,并采用数据挖掘技术—支持向量机建立电力信息系统网络安全态势评估模型,最后进行了电力信息系统网络安全态势评估仿真测试。结果表明,本文模型可以描述电力信息系统网络安全态势,获得了高精度的电力信息系统网络安全态势评估结果,而且电力信息系统网络安全态势评估综合性能要优于其它模型,具有更高的实际应用价值。     

基于人工神经网络的电力系统精细化安全运行规则

随着大规模可再生能源不断并网,对电网的实时调控能力提出了更高的要求。传统的基于在线关键断面自动发现以及基于连续潮流的在线极限传输容量计算方法,模型复杂、计算周期长,难以做到在线运行。从数据驱动的角度出发,首先将电网实时运行状态的潮流量抽象为该时刻电网的运行特征;然后对所有特征进行聚类和分布式特征选择;最后运用人工神经网络建立所选特征与关键断面极限传输容量之间的对应关系。算例分析表明,所提基于人工神经网络的电力系统精细化安全运行规则,在保证时间效率的前提下,能够在一定程度上提高关键断面极限传输容量的预测准确度。     

A nonlinear geometric approach to power system excitation control and stabilization

In this paper, a unified approach to the design of a nonlinear excitation controller/power system stabilizer for a synchronous generator/infinite bus power system is presented. The approach is based on a form of state feedback linearization, known as input–output feedback linearization, which provides an exact semi-global state transformation that is valid for a large class of operating points of the power system. With this transformation, the terminal voltage becomes a linear function of the control input. The excitation controller/power system stabilizer is then synthesized by using linear controller design techniques. The controller is proven to provide small signal stability and to provide local asymptotic tracking of admissible constant reference signals for a large class of operating points. A procedure is given to tune the controller gains to provide significant damping of the power angle oscillations.     

A multiobjective approach to the short-term scheduling of ahydroelectric power system

This paper is concerned with the short-term scheduling of the Iguacu river hydroelectric power system, in Southern Brazil. The system comprises four power plants with an unusual high coupling, held by two different utilities. Even though government regulations establishes operation guidelines, electric utilities have their own interests. A multiobjective framework is adopted to study the operation of the power system. Dynamic programming is used to find optimal solutions, with an implementation based on the concept of differential dynamic programming. A case study shows the possibility of obtaining energetic gains with the adoption of nonconventional operation rules and the need of negotiation to avoid wasting energy     

电力系统应急通信电源装置的研制

为提高通信设备应急保电工作的效率,保障各变电站及各县、市供电局通信设备后备电源供电可靠性,针对通信保电工作模式存在的问题,研制了电力系统应急通信电源装置。并对装置进行了性能测试。应用结果表明：该装置有效地解决了应急通信设备保电工作中设备接线速度慢,可靠性、稳定性差的问题,简化了应急保电工作步骤,便于应急保电工作人员操作。     

基于GPRS的电力SCADA系统安全功能设计

介绍了一种利用GPRS无线技术对远程设备进行数据采集和监控的系统解决方案，以及在此基础上针对电力系统实际应用环境设计的安全功能。还介绍了其在实际中的实现方法，这种方法很好的解决了远程监测系统的通信问题。