基于一致性算法的微网无功控制及延时算法优化

针对孤岛微电网中无功功率分配、通讯延时等问题,文中提出了一种基于一致性算法的分层控制算法。各分布式电源在时钟周期下与相邻的分布式电源交换电压信息,通过本地电压一致性算法得到全网平均电压值,可随迭代周期更新电压状态值,以实现各分布式电源无功功率的精确分配。电压一致性算法中,本地节点与相邻节点存在通讯延时,由微电网系统的拓扑结构可得到相邻节点间最大通讯延时时间,并由PI算法动态补偿延时误差。在MATLAB/Simulink平台搭建孤岛型微电网仿真模型,实验结果证明了控制策略的有效性。     

矿井互逆双环光纤主干通信网研究

结合下一代矿区通信网分层模型和矿井通信网的总体架构,提出矿井通信网的整体拓扑结构应该是:主干部分沿主要巷道构成光纤自愈环,在地面与矿区通信环网相切,井下其它部分则根据巷道分布特点、信息流量和可靠性等要求,构成分支树型或局部环型,就近连接到主干环的结点上.矿井主干环采用互逆双环拓扑结构,通过空间重利用技术提高带宽利用率,采用插入缓冲技术实现数据的快速转发.     

基于电力线通信的网络拓扑结构重建技术

电力线通信在智能电网中起到了愈发重要的作用。除了传输信息以外,对电力线网络自身结构的感知也是电力线通信的重要功能之一。通过将电力线网络建模为一个树型网络,同时充分利用电力线通信“通过电网”的特性,恢复电力线网络拓扑结构的能力成为可能。利用电力线网络的信道模型,通过节点之间信号的收发实现了电力线网络拓扑结构的估计。先后利用了矩阵束方法和动态重建方法,仿真结果显示,两种方法可以高概率地正确恢复网络结构,并且高精度地对电力线网络拓扑结构的细节进行恢复。     

A hybrid relay control mechanism for ribbon topology in low‐voltage power line communication networks

The communication reliability and distance of the low‐voltage power line communication system are seriously affected by the channel interference and the time variant load impedance. Therefore, how to control the relay nodes to reduce the communication delay and improve the communication reliability is mainly considered in the design. A novel hybrid relay control mechanism (HRCM) that includes the static relay pre‐configuration and the dynamic relay selection is designed for the ribbon topology in the low‐voltage power line communication networks. In the ribbon topology, the initial configuration for the communication link is realized through the pre‐configure relay nodes, which guarantees that the concentrator can communicate with the furthest terminal node. During the normal operations, the dynamic relay node is selected according to the sequence number of the uplink or downlink data frame and the data discard strategy. With the relay node dynamical selected mechanism, the frame repeated transmission can be avoided and the communication delay is reduced. The actual test results show that the hybrid relay control mechanism can effectively extend the communication distance, improve the communication real‐time and the reliability of the low‐voltage power line communication. Copyright © 2014 John Wiley & Sons, Ltd.     

基于高频同步采集与边缘计算的低压配电网电气拓扑发现技术

首先介绍了低压配电网拓扑发现技术现状,其次详细介绍了基于高频同步采集与边缘计算的低压配电网电气拓扑发现技术,包括数据的高频同步采集、利用皮尔逊相关系数法进行台区识别、分析电表之间的互信息、通过生成树算法生成物理拓扑等,最后进行验证和结果展示。与其他通过纯软件算法实现拓扑发现的方法相比,所提方法既能保证数据的同时性又可及时反映拓扑的变化,使得低压台区电气拓扑判断更加精准。     

A Bluetooth Based Sensor Network for Civil Infrastructure Health Monitoring

Communicating with sensors has long been limited either to wired connections or to proprietary wireless communication protocols. Using a ubiquitous and inexpensive wireless communication technology to create Sensor Area Networks (SANs) will accelerate the extensive deployment of sensor technology. Bluetooth, an emerging, worldwide standard for inexpensive, local wireless communication is a viable choice for SANs because of its inherent support for some of the important requirements – low power, small form factor, low cost and sufficient communication range. In this paper we outline an approach, centered on the Bluetooth technology, to support a sensor network composed of fixed wireless sensors for health monitoring of highways, bridges and other civil infrastructures. We present a topology formation scheme that not only takes into account the traffic generated by different sensors but also the associated link strengths, buffer capacities and energy availability. The algorithm makes no particular assumptions as to the placement of nodes, and not all nodes need to be in radio proximity of each other. The output is a tree shaped scatternet rooted at the sensor hub (data logger) that is balanced in terms of traffic carried on each of the links. We also analyze the scheduling, routing and healing aspects of the resulting sensor-net topology.     

Energy efficient network design tool for green IP/Ethernet networks

An innovative energy-efficient network design algorithm and a tool to lower the network power consumption are proposed. The goal is an energy efficient network that carries its rated communication load while meeting the QoS requirements by using the minimum set of nodes and links. QoS metrics include hop limit, bandwidth limit reliability and stability. The proposed algorithm addresses the set-covered problem. To discover the optimum network configuration efficiently, we propose a network configuration generation algorithm that utilizes DAPDNA-2, a parallel data flow type reconfigurable processer. The processor automatically produces the node/link set in n-digit binary form where links are modeled as “1” for power on and “0” for power off; it also confirms that the QoS requirements are satisfied. Evaluation results show that DAPDNA-2 is 2-orders faster than the conventional sequential method running on a Pentium-4 processor. Prototype Gigabit Layer-2 switches having remote link power on/off and traffic monitoring functions are developed. Using these switches, we successfully demonstrate an energy efficient IP/Ethernet network. The evaluation results show that network power savings of up to 30% can be realized under the NFSNET topology model. The proposed algorithm and power efficient network architecture can be applied to realize the future green network.     

塑料光纤在智能电网通信中的应用分析

我国＂十二五＂电网发展规划明确指出,要加快智能电网的建设,实现电力光纤入户。智能电网建设的关键技术之一是电力通信。目前,由于我国电力通信专用网呈现＂骨干网强、接入网弱＂、＂高（电压）端强,低端弱＂的态势,配电、用电环节的通信水平相对输电网而言差距较大,而智能配电和用电建设是智能电网用电环节的一个重要组成部分。因此,智能电网中的＂最后一百米＂显得尤为重要。伴随着光纤生产技术的发展,塑料光纤以其芯径大、柔韧性好、接续方便等特点,即将成为接入网的传输媒质。     

电力光通信网中风险均衡路由算法研究

在大力发展智能电网的背景下,支撑电网运转的电力光通信网规模日趋庞大,其承载的业务更加多样化.然而电力光通信网的业务路由规划主要以最短路径算法为主,导致电力光通信网存在业务重要度分布不均衡,从而导致网络局部风险过高的问题.针对上述现状,文章采用深度强化学习技术,以网络业务风险均衡为目标,提出了基于强化学习的电力光通信网风...     

A design technique for reliable networks under a nonuniform trafficdistribution

Many network-reliability analysis techniques define and compute a variety of reliability measures. Most techniques assume that network connectivity is the only determining factor in network reliability; and merely analyze an existing network structure but do not provide any methodology for reliable design. This paper presents a heuristic design algorithm to enhance the reliability of existing communication networks by modifying their topology. This algorithm improves the reliability of the least reliable node (reliability is the probability that messages transmitted from a given node reach their destination). To use this algorithm on large networks, a reliability analysis method is developed which determines approximate network reliability values in linear-time when an upper bound is placed upon the in-degree of all network nodes. The heuristic network design algorithm uses this approximate reliability analysis technique to place additional links. The goal of this link placement is to improve the reliability of the least-reliable node. The placement of additional links is a function of both the traffic distribution and the connectivity of the network. This process continues until either a desired level of network reliability is achieved or a maximum number of additional links has been added. A unique feature of this design strategy is that it has quadratic time-complexity when the maximum in-degree of all network nodes is limited     

一种基于最短路径树的无线Ad hoc网络拓扑维护算法

该文主要研究了无线Ad hoc网络中节点失效的情况下,如何维护网络的连通性和拓扑的性能,并且尽可能地降低拓扑维护的开销。提出了基于最短路径树的拓扑维护算法。该算法在拓扑变化时首先触发失效节点的邻节点响应(即重新运行拓扑控制算法),在不增加额外通信开销的情况下,响应的节点根据相互发送的Hello分组来判断网络是否连通;如果不能确定网络是连通的,再触发失效节点的其它可达邻近节点响应。仿真研究表明,算法显著地减少了拓扑维护的开销,维护后的拓扑结构在功率有效性和功率扩展因子等方面也取得了好的性能。     

基于链路可靠性的无线虚拟网络分配方法

针对无线网络链路可靠性差影响无线虚拟网络的分配这一问题,提出了一种基于链路可靠性的无线虚拟网络分配算法（WVNEA-LR）。该算法通过物理网络拓扑预处理和允许同一个虚拟请求中的多个虚拟节点映射到同一个物理节点上的方法,提高了Vn构建成功率和节约了物理链路资源。利用Q因子改善了因拓扑分配稀疏时Vn构建成功率低的问题。此外,WVNEA-LR的节点分配为链路分配作了准备,并通过选择可靠性高的承载路径保证了分配后的Vn具有高可靠性。仿真结果表明, WVNEA-LR获得较好的虚拟网络构建成功率、较高的收益成本比和资源利用率。     

配电网中故障指示器的低功耗无线同步技术

随着故障指示器在配电网中的广泛应用,国家电网对三相采集单元之间的同步误差及无电流时采集单元的最低功耗的要求越来越高。本文介绍了故障指示器的特点与应用需求,通过引入无线传感器网络的TPSN算法和时间片轮转通信机制,提出了一种高精度低功耗的无线同步通信技术,并进行了具体的设计和系统测试,测试结果表明该无线同步通信技术同步精度高、功耗低,完全满足国网对故障指示器提出的标准,现场运行证明了系统设计的可靠性。     

Reliability Evaluation of a Network with Delay

In a computer or communication network, the reliability and transfer-delay of communication are important measures of performance. This paper describes a method of evaluating the reliability of a network with delay. When network elements fail, delay is defined as the length of the shortest remaining path between two specified nodes. We find the occurrence probability of events that a central node can communicate with a group of terminal nodes so that a specified delay is not exceeded. The desired events are mutually exclusive and contain a tree. Our algorithm efficiently generates all the events by noting network topology. The paper includes the case of several central nodes.     

Reliability optimization of computer-communication networks

The evaluation of the reliability of a given computer communication network is a NP-hard problem. Hence, the problem of assigning reliabilities to links of a fixed computer communication network topology to optimize the system reliability is also NP-hard. A heuristic method is developed to assign links to a given topology so that the system reliability of the network is near optimal. The method provides a way to assign reliability measures to the links of a network to increase overall reliability. It is based on the principle that the most reliable link should be assigned to the most vulnerable edge. The method computes an importance order for the edges of the network and uses the order to assign link reliabilities. If there are fewer than six links in a network, it can be shown that the method gives optimal assignment     

考虑负载均衡的系统保护通信专网路由规划方法

针对系统保护通信专网局部节点与链路业务负载过重的问题,提出一种考虑负载均衡的系统保护通信专网路由规划方法.首先,阐述了系统保护通信专网的概念,分析了局部节点和链路业务负载过重的问题;然后,构建了综合考虑业务特性和备份路径的负载均衡路由规划优化模型,实现了模型的负载均衡路由规划求解;最后,以某省系统保护通信专网光传送网(...     

基于LEACH路由协议的混合光无线传感网络研究

分析了基于低功耗自适应分簇(LEACH)路由协议的无线传感网络(WSN)在不同拓扑形状下的生命周期,并改进了长方形拓扑形状的路由协议。进而针对WSN在某些场合能量有限、易受干扰和安全性差等缺点,在长方形区域中引入分布式光纤传感结构。将传感光纤铺设在环境复杂和外界电磁波干扰大的监测区域,从而提高整个传感网络的生命周期和可靠性。理论分析和仿真结果表明,改进的拓扑和协议在提高可靠性的同时,有效地延长了光WSN的生存时间,性能优于传统LEACH协议。     

一种基于链路质量的自维护拓扑控制博弈算法

针对无线传感器网络拓扑性能优化单一的问题,本文首先定义了表征双向通信质量的指标.其后将链路质量,节点干扰,剩余能量均衡性等参数融入收益函数,设计了一种基于链路质量的自维护拓扑控制博弈算法SMGLQ.理论证明该算法能保证各节点收敛到帕累托最优.仿真实验表明它能为网络选择通信质量较好的链路,并降低能耗.     

求网络总可靠度的状态空间树法和精确分解算法

本文提出了求通信网络总可靠度的状态空间树法。它直接产生网络图的一个不交化树多层多项式,优点是计算量较小[计算时间复杂度为0(?),(?)为边数,n_1为叶数],所得表达式较短。在此基础上应用超图理论提出了求通信网络总可靠度的精确分解算法。用它进行网络图的m次分解,一台计算机所能计算的通信网络规模可以扩大m倍。     

IEEE802.15.4标准的无线传感器网络自组网方案

无线传感器网络需要低功耗短距离的无线通信技术,IEEE 802.15.4标准就是针对低速无线个人区域网络的无线通信标准,把低功耗、低成本作为设计的主要目标,由于IEEE 802.15.4标准定义的LR-WPAN网和无线传感器网络存在很多相似之处.所以把它作为无线传感器的无线通信平台.在分析LR-WPAN网的网络拓扑及形成过程的基础上,实现无线传感器网络的自组网方案.