Security Risk Assessment of Cyber Physical Power System Based on Rough Set and Gene Expression Programming

Risk assessment is essential for the safe and reliable operation of cyber physical power system. Traditional security risk assessment methods do not take integration of cyber system and physical system of power grid into account. In order to solve this problem, security risk assessment algorithm of cyber physical power system based on rough set and gene expression programming is proposed. Firstly, fast attribution reduction based on binary search algorithm is presented. Secondly, security risk assessment function for cyber physical power system is mined based on gene expression programming. Lastly, security risk levels of cyber physical power system are predicted and analyzed by the above function model. Experimental results show that security risk assessment function model based on the proposed algorithm has high efficiency of function mining, accuracy of security risk level prediction and strong practicality. © 2014 Chinese Association of Automation.

信息物理生产系统(CPPS)面临的安全挑战与解决思路

信息物理生产系统(CPPS)具有互联互通、高度集成、人机协同、数据驱动等特点,使其对工业生产过程可实施高效管控,同时也带来诸多安全挑战,包括传统预防/减轻措施降险能力减弱,信息物理深度融合、智能化等新技术和新产品带来的新的不可接受风险等,急需解决新形势下的功能安全问题、信息安全问题以及功能安全与信息安全协同问题。本文梳理了CPPS安全挑战与安全领域的映射关系,提出了协同功能安全和信息安全的安全一体化解决思路。

Cyber-Physical Systems as General Distributed Parameter Systems:Three Types of Fractional Order Models and Emerging Research Opportunities

Cyber-physical systems (CPSs) are man-made complex systems coupled with natural processes that, as a whole, should be described by distributed parameter systems (DPSs) in general forms. This paper presents three such general models for generalized DPSs that can be used to characterize complex CPSs. These three different types of fractional operators based DPS models are: fractional Laplacian operator, fractional power of operator or fractional derivative. This research investigation is motivated by many fractional order models describing natural, physical, and anomalous phenomena, such as sub-diffusion process or super-diffusion process. The relationships among these three different operators are explored and explained. Several potential future research opportunities are then articulated followed by some conclusions and remarks. © 2014 Chinese Association of Automation.

大数据技术下微电网CPPS发展研究挑战和展望

微电网及其控制系统是一种典型的信息物理系统(Cyber-Physical Power System,CPPS)。微电网智能化的深入发展,使得跨领域数据量激增,且数据的规模与特点符合大数据特征。文章以大数据分析技术为基础,探讨微电网电力物理信息融合发展下电力大数据技术的特征、研究挑战及其在相关领域的发展趋势。

基于网络依存关系的CPPS连锁故障分析及风险评估

信息系统的融合给电网安全运行带来了新的风险,因此有必要研究电力信息物理系统(cyber-physical power system,CPPS)连锁故障的产生及传播机理。首先建立CPPS部分相互依存模型,采用老化因素、潮流、隐性故障、偶然因素构建电网风险元,采用信息占用率、拓扑结构、网络攻击、节点负荷以及依存关系构建信息网风险元,从而将风险元理论应用于CPPS连锁故障预测过程。其次提出一种同时考虑两网失负荷率的风险计算方法,可以识别骨干层与接入层的关键节点。最后分析信息节点自身故障和网络攻击引起的信息节点失效对连锁故障的不同影响。算例分析表明:依存关系会促进故障在两网传播,增大系统的风险;对CPPS进行整体分析能较全面地评估连锁故障风险,识别关键信息节点;同时遭受网络攻击与信息节点自身故障的CPPS的平均风险最高,需采取措施提高其可靠性。

电力信息物理系统故障通信恢复策略

极端灾害将导致电力系统与通信系统同时发生大面积瘫痪,基于“保电救灾、通信先行”原则,优先恢复故障通信是支撑保障电力系统安全运行的关键。该文针对灾后电力通信高效恢复问题,提出了一种计及电力侧状态感知需求与运行调控能力保障的增广路径最大流电力通信网络恢复算法。首先考虑到电力通信系统与电力物理系统的紧耦合特性,设计了计及电力侧影响的状态感知与运行调控能力量化指标,辨识关键信息节点。然后,通过图论最大流理论,搜寻关键信息节点的增广路径集。在此基础上,引入恢复贡献度,从增广路径集中选择具有大容量、低延时以及少故障链路的通信路径进行优先重建,为灾后电力系统快速恢复过程提供可达、可靠的通信支撑。最后,以IEEE39标准系统作为仿真算例,验证了所提恢复策略下的通信系统具有更高的通信服务质量(quality of service,QoS),避免了在恢复过程中由于带宽容量不足而发生业务频繁掉线风险。

计及次生灾害影响的电力信息物理系统恢复方法研究

在极端自然灾害愈加频发的背景下,电网调度人员不仅需要考虑如何调度维修资源加快电力信息物理系统的恢复,还需要考虑如何降低引发的次生灾害造成的负面影响。针对上述问题,提出了一种计及次生灾害影响的电力信息物理系统恢复方法,根据信息物理协同的特点和次生灾害发生的概率调度维修资源至受灾区域,减少停电损失。首先,建立了基于以太无源光纤网络和应急电源协同的电力信息物理系统模型,研究信息网络和物理网络对系统韧性提升的效果。然后,提出了一种计及次生灾害影响的协同维修方法,并与单独维修方法进行对比。最后,搭建了一种求解所提恢复方法的分析框架,并在IEEE 33节点系统上进行仿真,确定最佳的维修资源调度策略。仿真结果表明,所提方法能降低次生灾害造成的负面影响、提高维修资源的利用率。

Modeling cascading failures and mitigation strategies in PMU based cyber-physical power systems

This paper presents a model of cascading failures in cyber-physical power systems(CPPSs) based on an improved percolation theory, and then proposes failure mitigation strategies. In this model, the dynamic development of cascading failures is divided into several iteration stages. The power flow in the power grid, along with the data transmission and delay in the cyber layer, is considered in the improved percolation theory. The interaction mechanism between two layers is interpreted as the observability and controllability analysis and data update analysis influencing the node state transformation and security command execution. The resilience indices of the failures reflect the influence of cascading failures on both topological integrity and operational state. The efficacy of the proposed mitigation strategies is validated, including strategies to convert some cyber layer nodes into autonomous nodes and embed unified power flow controller(UPFC) into the physical layer. The results obtained from simulations of cascading failures in a CPPS with increasing initial failure sizes are compared for various scenarios.Dynamic cascading failures can be separated into rapid and slow processes. The interdependencies and gap between the observable and controllable parts of the physical layer with the actual physical network are two fundamental reasons for first-order transition failures. Due to the complexity of the coupled topological and operational relations between the two layers, mitigation strategies should be simultaneously applied in both layers.

Concept and Research Framework for Coordinated Situation Awareness and Active Defense of Cyber-physical Power Systems Against Cyber-attacks

Due to the tight coupling between the cyber and physical sides of a cyber-physical power system(CPPS),the safe and reliable operation of CPPSs is being increasingly impacted by cyber security.This situation poses a challenge to traditional security defense systems,which considers the threat from only one side,i.e.,cyber or physical.To cope with cyberattacks,this paper reaches beyond the traditional one-side security defense systems and proposes the concept of cyber-physical coordinated situation awareness and active defense to improve the ability of CPPSs.An example of a regional frequency control system is used to show the validness and potential of this concept.Then,the research framework is presented for studying and implementing this concept.Finally,key technologies for cyber-physical coordinated situation awareness and active defense against cyber-attacks are introduced.

Progress and prospects of innovative coal-fired power plants within the energy internet

The development of electrical engineering and electronic, communications, smart power grid, and ultra-high voltage transmission technologies have driven the energy system revolution to the next generation: the energy internet. Progressive penetration of intermittent renewable energy sources into the energy system has led to unprecedented challenges to the currently wide use of coal-fired power generation technologies. Here, the applications and prospects of advanced coal-fired power generation technologies are analyzed. These technologies can be summarized into three categories:(1) large-scale and higher parameters coal-fired power generation technologies, including 620/650/700 oC ultra-supercritical thermal power and double reheat ultra-supercritical coal-fired power generation technologies;(2) system innovation and specific, highefficiency thermal cycles, which consist of renewable energy-aided coal-fired power generation technologies, a supercritical CO_2 Brayton cycle for coal-fired power plants, large-scale air-cooling coal-fired power plant technologies, and innovative layouts for waste heat utilization and enhanced energy cascade utilization;(3) coal-fired power generation combined with poly-generation technologies, which are represented by integrated gasification combined cycle(IGCC) and integrated gasification fuel cell(IGFC) technologies. Concerning the existing coal-fired power units, which are responsible for peak shaving, possible strategies for enhancing flexibility and operational stability are discussed. Furthermore, future trends for coal-fired power plants coupled with cyber-physical system(CPS) technologies are introduced. The development of advanced, coal-fired power generation technologies demonstrates the progress of science and is suitable for the sustainable development of human society.

Consensus of cyber-physical power systems based on multi-agent systems with communication constraints

The consensus protocol of cyber-physical power systems is proposed based on fractional-order multi-agent systems with communication constraints.It aims to enable each generator to reach a time-varying common rotor angle and rotor speed.Communication constraints including event-triggered sampling and partial information transmission are considered to render the consensus protocol more realistic.The Zeno behavior is excluded during the system sampling process.A sufficient condition is derived to solve the consensus problem.The effectiveness of the proposed consensus protocol is demonstrated by a numerical example.

Deducing cascading failures caused by cyberattacks based on attack gains and cost principle in cyber-physical power systems

To warn the cascading failures caused by cyberattacks(CFCAs)in real time and reduce their damage on cyber-physical power systems(CPPSs),a novel early warning method based on attack gains and cost principle(AGCP)is proposed.Firstly,according to the CFCA characteristics,the leading role of attackers in the whole evolutionary process is discussed.The breaking out of a CFCA is deduced based on the AGCP from the view of attackers,and the priority order of all CFCAs is then provided.Then,the method to calculate the probability of CFCAs is proposed,and an early warning model for CFCA is designed.Finally,to verify the effectiveness of this method,a variety of CFCAs are simulated in a local CPPS model based on the IEEE 39-bus system.The experimental results demonstrate that this method can be used as a reliable assistant analysis technology to facilitate early warning of CFCAs.

Risk-based method to secure power systems against cyberphysical faults with cascading impacts: a system protection scheme application

The utilization levels of the transmission network can be enhanced by the use of automated protection schemes that rapidly respond to disturbances. However,such corrective systems may suffer from malfunctions that have the potential to exacerbate the impact of the disturbance. This paper addresses the challenge of jointly optimizing the dispatch of generators and protection settings in this context. This requires a holistic assessment of the cyber(protection logic) and physical(network) systems,considering the failures in each part and their interplay.Special protection schemes are used as a prototypical example of such a system. An iterative optimization method is proposed that relies on power system response simulations in order to perform detailed impact assessments and compare candidate solutions. The candidate solutions are generated on the basis of a security-constrained dispatch that also secures the system against a set of cyber failure modes. A case study is developed for a generation rejection scheme on the IEEE reliability testsystem(RTS): candidate solutions are produced based on a mixed integer linear programming optimisation model, and loss-of-load costs are computed using a basic cascading outage algorithm. It is shown that the partial security approach is able to identify solutions that provide a good balance of operational costs and loss-of-load risks, both in a fixed dispatch and variable dispatch context.

“新型电力系统数字化关键技术综述”专辑评述

数字化是推动新型电力系统发展的重要动力,已成为广受学术界和产业界关注的热点技术。为此,《电力系统自动化》编辑部组织了“新型电力系统数字化关键技术综述”专辑,系统化介绍了新型电力系统数字化基础元件装备、边缘计算技术、通信安全与防护、智能化调度决策等一系列技术成果,代表了本领域最新技术成果和先进经验。文中立足于新型电力系统数字化发展的整体趋势,对专辑论文按研究方向进行了系统性梳理,对其核心成果与观点进行了归纳总结,希望能够完整呈现专辑成果对新型电力系统数字化关键技术体系的支撑作用,为相关技术研究的进一步深化提供参考。

电力信息物理系统中信息系统物理化的建模及分析方法

该文基于信息系统物理化的设想提出电力信息物理系统(cyber-physical power system,CPPS)中的信息流建模和计算分析方法。采用连续时间函数来刻画信息流的特征,并定义信息网络运行参数为流量累积函数、信息流速和时延。首先,基于遍历法搜索出信息流路径,建立信息流速矩阵的范式;然后利用改进的网络演算(network calculus,NC)特性赋值流速矩阵的元素;进一步采用流量累积函数表征信源数据发送规律,从而显式求解时延上界。最后将提出的信息流建模方法应用于智能变电站自动化系统的时延计算,通过与OPNET的仿真结果相比较,验证所提出模型的有效性,而且该方法可以提供定量分析指标以优化变电站组网方案设计中的信息流分布。

基于SDN的配电网信息-物理协同恢复策略

随着智能电网的快速发展,配电网中信息物理耦合关系日益紧密。这种耦合性使得配电网更容易被多方面极端事件所影响,在通信网络发生故障时会降低系统的态势感知和控制能力,从而制约配电网的灾后负荷恢复能力,因此通信网络恢复对灾后配电网负荷恢复至关重要。该文提出一种通信网络恢复和负荷恢复的协同优化决策方案,该方案将环网通信网络与软件定义网络(software defined networking,SDN)技术相结合,灵活恢复灾后的配电网通信网络,进而控制配电网拓扑重构形成以分布式电源为中心的微电网以恢复负荷电力供应,并进一步使用一种信息物理协同的启发式计算方法实现恢复方案的快速计算。最后,使用IEEE 33节点和IEEE 123节点测试系统验证所提出方法的优点和有效性。

电力信息物理系统跨域攻击协同防御架构及机制研究

我国电力基础设施已经发展成为具有高度信息化、自动化、智能化特征的信息物理融合系统.信息-物理交互在显著提升电力供给效率和性能的同时,也引入了新型网络安全威胁,通过发生于信息域并明确作用于物理域的跨域攻击,可造成电力基础设施系统性瘫痪,继而引发大面积停电事故,而当前孤立的信息侧或物理侧防御体系难以有效应对跨域攻击威胁.本文介绍了电力系统面临的信息物理跨域攻击威胁现状,分析了传统防御方法面对跨域攻击时存在的不足,提出了一种信息物理协同的跨域攻击防御架构,在针对跨域攻击传播的不同阶段,从感知、辨识、阻断三个角度设计了防御方法,通过算例验证了所提信息物理协同防御架构能够有效保障电力系统安全稳定运行.

基于CPSS视角的需求响应能力评估综述

对信息—物理—社会系统与需求响应评估的结合进行综述。首先对信息物理系统的历史和框架进行分析。接着总结了现有的需求响应研究现状,包括需求响应潜力评估的意义、分类和评估方法。对于需求响应能力评估的数据来源进行总结,包括问卷调查和运行数据采集。在信息—物理—社会系统与需求响应结合方面,分别分析需求响应的物理域、信息域和社会域基础,介绍相应的建模方法和研究内容。最后,对未来的研究展望进行讨论,包括市场考核机制、快速仿真与建模技术以及综合能源下的需求响应管理。

考虑信息物理融合系统的韧性电网风险研究现状及发展趋势可视化分析

为探究韧性电网信息物理融合系统风险研究现状及发展趋势,基于中国知网(CNKI)和Web of Science(WoS)数据库2011—2023年的文献数据,利用CiteSpace对该领域研究的研究热点、前沿及演化趋势进行可视化分析。研究结果表明:国内研究形成以“风险预警与控制”和“电力系统智能化建设”为主题的研究热点,国外研究形成以“信息物理融合”和“连锁故障演化”为主题的研究热点;“智能电网的信息物理耦合”和“信息网络攻击风险分析”是国内研究的前沿方向,“信息物理融合系统安全状态估计”和“风险防控模型”是国外研究的前沿方向;国内研究可分为安全性理论研究期、信息物理攻击风险研究期和故障防御恢复研究期3个时间阶段,国外研究可分为信息物理融合研究期和信息物理安全应用期2个时间阶段;后续研究应加强改进电力信息物理融合系统建模、完善电力信息物理融合系统规划、推进电力信息物理融合系统应用,推进数字化韧性电网稳定运行。研究结果可为韧性电网风险识别和风险预警研究提供一定参考。

信息-物理-社会视角下的电力-交通耦合网络建模与协同优化

近年来,电动汽车(EV)、快速充电设施的高速增长将电力系统和交通系统这两个复杂的基础设施网络紧密耦合。EV具备充电时间和充电位置的灵活性,对于新型电力系统正是理想的移动储能资源,可提供规模巨大的时间、空间灵活调节能力。然而,宏观的电力-交通耦合背后是海量EV用户在各类信息引导下做出的微观社会化决策,构成了复杂的信息-物理-社会系统。从这一视角对电力-交通耦合网络建模分析与协同优化的相关研究进行了梳理。首先,对两网耦合的基本场景和关键挑战进行了介绍;接着,以社会层与物理层为重点归纳了融合微观车主决策与宏观网络动态的EV群体出行-充电行为建模方法;然后,进一步纳入信息层,总结了多类定价主体与EV间的策略交互与协同优化;最后,对电力-交通耦合网络建模分析与协同优化相关方向的研究进行展望。