Improved-ELM method for detecting false data attack in smart grid

Power grid is a complex system which closely links the power generation and power consumer through transmission and distribution networks. With the development of smart grid, smart grid is more open to external communication systems, it also has exposed some problems in the network attacks. A new false data injection attack (called the unobservable attack) that can bypass the traditional BDD and inject random errors into state estimation. We propose an improved extreme learning machine (ELM) for attack detection. The artificial bee colony (ABC) incorporates the thought of differential evolution algorithm (DE) to optimize ELM for improving detection precision. In this paper, Autoencoder is used to reduce the dimensionality of the measurement data, which makes the low-dimensional data information basically and fully represent high-dimensional data. We verify the performance of the proposed method on IEEE bus systems, and prove that the proposed method can effectively detect such unobservable attack.     

变电站内传输IEC 62351通信密钥的加密传输方法

随着智能变电站信息化水平的提高，通信系统的网络安全问题日益凸显。而以认证加密为核心的网络安全解决方案，如IEC62351标准，需要借助特定的安全传输通道来传输应用密钥。提出了一种在对称加密下实现通信密钥自动协商的方法来构造应用密钥的安全传输通道。该方法以高级加密标准算法及对称密钥组为基础，通过初始密钥结合随机数验证的方式实现了通信密钥的协商机制。协商后的通信密钥具有随机性特征，解决了传统对称加密所有通信使用同一密钥可能带来的安全风险问题。还在防重放、加密强度、抵御密钥失窃攻击等方面进行了技术分析。该方法具有很好的安全性，易用性，可为智能变电站网络安全系统的密钥传输提供借鉴。     

基于业务流量的配电通信网可靠性分析

电力通信网业务可靠性主要以网络中的业务数量为依据进行分析,未考虑每条业务在业务流量上的差异。针对这一问题,通过分析配电通信网络的结构、业务类型及分布,建立了配电通信网业务传输模型,提出了一种基于业务流量的配电通信网业务可靠性分析方法。通过实例分析了此方法相比于原有基于业务数量的可靠性分析方法的优势。仿真结果验证了所提方法的可行性。     

基于结构熵的电力骨干通信网抗毁性研究

电力骨干通信网抗毁性分析对于评价电力通信网络的生存性能,制定网络的保护策略具有重要的意义。结合复杂网络异构性,基于电力骨干通信网拓扑结构,构建了网络节点差异性矩阵。依据电力通信的业务特点,将链路传输流量作为链路的权重,构建了网络链路差异性矩阵。融合节点及链路差异性定义了节点重要度及电力骨干通信网的结构熵。以一个实例网络对网络的节点重要度及蓄意攻击下以结构熵为指标的网络抗毁性进行了仿真分析,结果表明了所提方法的合理性和有效性。     

针对网络通信中认证和密钥建立协议的假冒攻击

为了保障信息在无线系统中的安全传输,用户和服务器在交换信息之前需要相互认证,并在建立1个共享的会话密钥。对邓方民提出的基于椭圆曲线的相互认证和密钥建立协议的安全性进行分析,指出协议本身存在的安全隐患。     

智能变电站嵌入式终端的网络攻击类型研究及验证

全面掌握智能变电站嵌入式终端可能遭受的网络攻击方式及其对电力一次系统的影响,是建立有效安全防护措施的基础。目前,有关智能变电站嵌入式终端网络攻击的研究大都针对单一类型的网络攻击,且仅停留在理论分析阶段,未对提出的网络攻击类型进行验证。在分析智能变电站嵌入式终端及其通信环境的脆弱性的基础上,从攻击检测所需要的数据源和检测方法角度总结了终端可能遭受的网络攻击类型;提出了实物与仿真相结合的攻击验证方案;分析了泛洪类和报文类主要攻击的原理,给出了相应攻击工具的构造方法;使用所构造的攻击工具在验证方案设计的实验环境中进行了测试,结果证明这些攻击会对智能变电站嵌入式终端及电力一次设备造成影响,且终端抵御泛洪类攻击能力较差。     

基于复杂网络的综合能源系统脆弱环节辨识

综合能源系统的脆弱环节辨识对于系统的安全经济运行具有重要意义,复杂网络理论为系统的脆弱环节辨识提供了思路。将应用于电网的带权重的线路介数概念引入到综合能源系统中,并根据综合能源系统特点进行了2点改进。在改进的带权重线路介数的基础上定义了带权重的节点介数。采用基于能源集线器的综合能源系统进行了脆弱性分析,衡量了脆弱环节受到破坏时对系统的影响。通过观察不同攻击策略下系统表现出的脆弱性,验证了所提方法的有效性。     

Effect of Marine Planktonic Algal Particles on the Communication Performance of Underwater Quantum Link

As one of the main application directions of quantum technology, underwater quantum communication is of great research significance. In order to study the influence of marine planktonic algal particles on the communication performance of underwater quantum links, based on the extinction characteristics of marine planktonic algal particles, the influence of changes in the chlorophyll concentration and particle number density of planktonic algal particles on the attenuation of underwater links is explored respectively, the influence of marine planktonic algal particles on the fidelity of underwater quantum links, the generation rate of the security key, and the utilization rate of the channel is analyzed, and simulation experiments are carried out. The results show that with the increase in chlorophyll concentration and particle density of aquatic planktonic algal particles, quantum communication channel link attenuation shows a gradually increasing trend. In addition, the security key generation rate, channel fidelity and utilization rate are gradually decreasing. Therefore, the performance of underwater quantum communication channel will be interfered by marine planktonic algal particles, and it is necessary to adjust the relevant parameter values in the quantum communication system according to different marine planktonic algal particle number density and chlorophyll concentration to improve the performance of quantum communication.     

考虑电网关联度的电力通信网关键环节识别

电力通信网作为电网的支撑网络,其可靠运行对电网安全可靠运行有着重要意义。为了识别电力通信网的关键环节,提出了一种考虑电网关联度的电力通信网关键环节识别方法。首先,构建电力-通信复合系统,其次,分别构建电力系统层节点评价体系、链路评价体系和通信系统层节点评价体系、链路评价体系,然后采用TOPSIS算法分别求得电力系统层节点重要度、链路重要度以及通信系统层节点重要度、链路重要度。最后,通过特定的代数运算,将电网关联度与通信网自身的重要度结合起来,分别求得考虑电网关联度的电力通信网节点、链路重要度值,并依据重要度值,识别出电力通信网关键环节。某省实际电力通信网仿真结果表明,该方法可以有效地识别出关键环节,证明了该方法的可行性。     

Control loops selection to damp inter-area oscillations ofelectrical networks

This paper reports on results of a study whose objectives is to demonstrate that a systematic, yet straightforward method based on well-known system theoretical analysis tools can be applied to select the control loops which improve the inter-area dynamic stability while minimizing the interactions among local and global controllers. Two complementary measures are involved in the measurement and control signals selection: the geometric measures which allow choice of signal pairs maximizing the controllability and observability of inter-area modes, and the singular-value based total interaction measure which focuses on minimizing the interactions between the local or global loops at the inter-area natural frequency. As a practical illustration of the proposed measurements and controllers pairing scheme, the linearized model of a nine areas twenty three generators power system involving nine inter-area modes is used. The results obtained show that communication links between areas may deem necessary on one hand to improve the inter-area modes observability-controllability and on the other hand to reduce the interaction between the control loops at the inter-area natural frequencies. The usefulness of such an analysis in minimizing the number of communication links without degrading the overall control system performance is highlighted     

一种电力通信网络运行质量量化评估方法及应用

研究了基于预期业务损失以及业务潜在风险程度评价的电力通信网络运行质量量化评估方法,提出失效业务比和影响业务比2个评价指标。基于该研究方法,以甘肃省电力骨干光通信网为实施案例,通过PSCPlanner网络仿真软件对骨干通信网实施N-1故障仿真分析,得出不同区域的骨干链路重要性以及运行质量分布情况,旨在为甘肃省公司各级电力光通信网的运行维护和升级改造提供指导。     

A Decision-Tree Scheme for Responding to Uncertainties in Microgrid Protection Coordination

In addition to the dynamic nature of microgrids, uncertainty in the proper operation of protection system and communication links are other challenges affecting the protection coordination of these networks. Therefore, in this paper, a new protection coordination plan based on decision tree for considering uncertainties in the topology of microgrid, protection system, and communication links is presented. The proposed method allows the adaptive protection to make global decisions and adopt the best strategy to clear faults depending on considered uncertainties. Since circuit breakers are the most prone to failure equipment in the protection system due to fault-caused stress, this paper models uncertainty in the protection system with uncertainty in the performance of circuit breakers. In order to consider uncertainty in circuit breakers and communication links, their probability of correct operation are not considered fixed but variable, respectively, proportional to the fault current flowing through the circuit breakers and the latency of communication links. The proposed plan was tested on a sample microgrid in DIgSILENT Power Factory. Results prove that using the proposed method, adaptive protection can establish an optimal sequence of strategies so that with the failure of each strategy, the best backup strategy is replaced given the uncertainties.     

The double-edged sword of secrecy in military weapon development

The Tomahawk missile is the United States Navy's premier land attack cruise missile and has enjoyed significant positive press during both Gulf Wars and in the recent strikes in Afghanistan. Considering the large and versatile weapon inventory of the U.S. military, it is no small achievement for a single weapon to be considered the "weapon of choice". In fact, the United States Air Force has its own land attack cruise missile called the Conventional Air-Launched Cruise Missile (CALCM). Both the Tomahawk and the CALCM were conceived and initially developed under the same Department of Defense (DoD) program, the Joint Military Cruise Program Office. These two missiles with nearly identical early development and missions experienced quite different fates. The success of the Navy's Tomahawk, a program with relatively low secrecy when compared to the Air Force's CALCM, should be a lesson to military managers of future weapons procurement programs.     

钻机电控系统PROFIBUS-DP总线通讯故障树分析

钻机电控系统PROFIBUS-DP总线通讯故障树分析,是快速诊断总线通讯故障的一种新方法。针对总线通讯网络并结合现场使用情况,建立PROFIBUS-DP总线通讯故障树。利用定性分析,求出总线通讯故障的最小割集和结构重要度。并对通讯故障影响因数进行了重要度排序,找出了薄弱环节,为钻机电控系统管理和维护人员提供参考依据。     

考虑多代理供电恢复系统通信失效的配电网CPS风险评估

提出一种考虑多代理供电恢复系统通信失效的配电网信息物理系统(CPS)风险评估方法。该方法将整个供电恢复过程分解为多个包含输入和输出的子任务,当通信系统失效时,依赖于失效通信链路的子任务将输出无效值,进而影响供电恢复的效果。通过计算不同供电恢复系统失效状态下的负荷缺额、恢复容量以及各个状态的概率,可以得到供电恢复后的电力不足期望值,并据此构建配电网CPS风险评价指标。通过计算并比较风险指标对各条通信链路丢包率的灵敏度大小,可以确定关键通信链路,并指出在通信系统的设计中应差异化提升这些通信链路的可靠性。最后,通过典型算例验证了所述方法的有效性。     

网络模式下配电物联网载波通信匹配组网方法

为进一步完善电力线载波通信技术在配电网中组网的灵活性及可靠性,结合拓扑实例,提出网络模式下配电物联网载波通信系统自适应匹配组网方法.构建配电网络链路通信质量矩阵,根据矩阵元素对网络中各通信节点进行区域网的划分及中继节点的选取,完成网络各通信节点的初步组网;在网络模式下采用混沌粒子群优化算法,依次对各区域网内部节点进行节...     

基于边临毁度的电力通信网脆弱性分析

电力通信网脆弱性分析对确保电力系统安全运行和加强电网健壮性具有重要意义。首先建立了电力通信网络模型,从网络的业务层、网络传输层和物理层指标出发,建立了基于临毁度和网络损失度的电力通信网的脆弱性评估和分析模型。接着对边的业务传输时延指标、带宽占比指标和物理故障概率指标评估得出网络部件(节点、边)的临毁度。最后结合网络部件失效后的系统损失度,得出网络部件的脆弱度评估值。以IEEE-30节点系统为例进行仿真,完成了通信网络部件的脆弱性评估分析,结果表明通信链路的长度和业务分配方案与电力通信网的脆弱性密切相关。     

Software technology issues for a US National Missile Defense System

The United States is currently developing a national missile defense (NMD) system designed to protect its territory from attack by strategic (long-range) ballistic missiles. In September 2000, President Clinton decided to defer the NMD deployment decision to the next president. President George W. Bush reaffirmed his administration's commitment to deploying a ballistic missile-defense shield by advocating an even larger NMD system in a speech at the National Defense University on May 1, 2001. The terrorist attacks of September 11, 2001, brought both the sense of deployment urgency for protection, and the call to transfer resources, from NMD to more likely terrorist threats. We focus exclusively on identifying and examining key technical challenges, primarily software-related, inherent to NMD     

Optical modeling of MEMS corner cube retroreflectors withmisalignment and nonflatness

Micromachined corner cube retroreflectors (CCRs) can be employed as transmitters in free-space optical communication links. In this application, a CCR is illuminated by an unmodulated beam, and one mirror of the CCR is intentionally misaligned to modulate the intensity of the retroreflected beam. The low power consumption, small size, and ease of operation of a CCR makes it an attractive option for certain types of optical links. However, curvature and misalignment of the micromachined mirrors can cause CCRs to perform far from theoretical limits. In this paper, we develop two methods to predict the optical performance of CCRs having ideal or nonideal mirrors. We first introduce a discretized analysis method based on ray tracing and scalar diffraction theory. We then propose a simpler phase-shift model under the assumptions that the misalignment and surface nonflatness are small and that they do not alter the optical topology of the CCR. These assumptions are satisfied by typical CCRs to be used in free-space optical links. Using our two methods, we determine tolerances on mirror curvature and misalignment for representative micromachined CCRs     

Stochastic security testing of chaos‐based communication systems against error function attack

This paper proposes two stochastic testing methods for the security analysis of a secure communication scheme based on continuous‐time chaotic systems. First, we define an instantaneous EFA (error function attack) function that does not include the average operation. Second, we propose a statistical testing for cryptanalysis, which calculates a standard deviation of the EFA function obtained by random trial keys. As another stochastic testing, moreover, we propose a stochastic evolutional attack to find a secret key. Finally, simulation results for the proposed security testing are presented. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.