用户供电质量需求识别与优质供电增值服务策略

优质供电的增值服务是电力公司提高售电竞争力的一项重要途径。优质供电是一个定性概念,采用供电质量指标进行定量刻画时,不同用户对优质供电的需求差异很大,供电企业不可能对每个用户提供完全不同的供电,基于对优质供电的需求类别,提供增值服务是更可行的方式。首先,研究用户对优质供电的多样性需求和供电公司的服务愿望,提出电能质量分类指标体系,包括用户价值指标和电能质量效用指标,刻画用户的电能质量需求;其次,基于所提的指标体系和各指标重要程度,建立用户供电质量需求类别识别模型,采用定性与定量相结合的方式,对用户供电质量类别进行划分,并设计了优质供电差异化增值服务套餐;最后,提出增值服务套餐成本-收益模型,实现对单个用户的增值服务内容的确定和增值服务价格的计算。实例分析证明了所提方法的合理性和有效性,为售电企业吸引新用户、开展差异化增值服务提供了参考。     

基于非侵入式负荷监测的用户行为精细化分析

随着非侵入式电力负荷监测的发展,如何利用用户负荷用电细节信息,分析用户用电行为特征成为重要的研究方向。本文提出了基于非侵入式负荷监测的用户行为精细化分析方法,根据历史数据建立用户行为特性指标,提出基于因子分析与支持向量机的用户聚类方法。在此基础上,建立基于精细化负荷数据的用户需求响应潜力评估指标。算例结果表明,所研究内容可以准确分析用户行为,为电力公司施行需求侧管理提供科学指导。     

基于用电效用与电器参数特征化的用户侧节能自趋优方法及其应用

用户侧管理节能是智能电网实现节能减排的重要环节,如何在保障用户用电体验的同时实现能源高效利用是用户侧能量管理系统的核心问题。理论分析上,基于用电效用的概念与电器参数化分析方法提出用户侧节能自趋优方法:引入效用函数作为评价用电满意度评价指标,并改进电器用电效用分级评价方法;基于自趋优思想提出用电侧节能自趋优优化思路;结合电器运行参数化思想提出电器运行节能指标的挖掘方法,包括电器运行状态自识别与用电需求挖掘;技术实现上,以时间扰动型电器为例,探讨用户侧节能自趋优方法理论的应用与电器特征参数化的技术实现方式;工程应用上,在广州某办公楼建设智能用电环境并部署节能策略,运行结果验证了该文方法在规模化工程应用方面的可行性与有效性。     

Flicker Source Tracing by Wavelet Transform

In the present day, voltage fluctuations (flicker) have received more attention by both utilities and consumers. Flicker mitigation needs identification of the flicker sources. After identifying the flicker sources, it would also be possible to penalize the relevant utility or the consumers. In this article, a new method based on flicker power theory and wavelet transform is proposed to identify the locations of single and multiple flicker sources in a multi-flicker source power network. The wavelet transform is utilized for demodulation and then the total flicker powers are computed by adding the flicker power belongs to individual flicker frequency components. The method also computes the contributions of each consumer and utility to the global flicker level of a common coupling busbar. For validation, the IEEE 13-bus network is simulated and an algorithm for flicker sources tracing is tested. Time-domain simulations in MATLAB/Simulink (The MathWorks, Natick, Massachusetts, USA) are performed to examine the accuracy of the proposed method. Simulation results show that by using the proposed method, all flicker sources and their contributions on the global flicker level can be detected correctly. To assess the performance of the proposed algorithm, the comparison with the most well-known methods has been presented.     

超密集物联网中的多蜂窝网络选择算法

随着物联网终端爆炸式的增加,物联网致密化成为发展的必然。在海量终端数量和资源严重受限的情况下,如何确定物联网终端设备的接入基站以及如何有效地为接入的用户进行资源分配,成为超密集物联网系统所需解决的重要问题。文章在吞吐量和系统能耗之间进行折中,以系统能效为优化目标,设计了一种超密集物联网中的多蜂窝网络选择算法。该算法为用户和基站设置效用函数,基于匹配理论完成用户的选择过程。最后对该算法和对比算法进行仿真,结果表明,多蜂窝网络选择算法在能耗和能效性能上均优于对比算法。     

K-means clustering and correlation coefficient based methods for detection of flicker sources in non-radial power system

Nowadays electric power quality problems such as flicker (voltage fluctuation) are major concern of electric companies and industrial consumers. Identification of flicker sources is an important stage in customers convincing and in flicker reduction process. For equal fluctuation frequency of flicker sources, detection of coupling points of these sources is not an easy task. In this paper, voltage envelope is extracted by Enhanced Phase-Locked Loop (EPLL), which acts as a nonlinear adaptive filter, and then the amplitude of flicker tone is used as a flicker index. The power system with arbitrary flicker sources is assumed and simulated to generate a set of training data. Then two methods based on K-means clustering algorithm and correlation coefficient are introduced to identify the location of flicker sources in a non-radial power system. Using proposed methods location of flicker sources with similar fluctuation frequency in non-radial power system is determined. In a typical test system, several simulations have been conducted. The simulation results show the performance of the proposed method is very promising and flicker sources can be detected tolerably.     

RAM versus CAM

Fifty years ago John von Neumann proposed the concept of the stored-program computer in which both instructions and data are confined within the boundaries of a storage device called memory. Today a computer architect is faced with a bewildering variety of memory-types to choose from when implementing this concept in the hardware. The most commonly used storage device is called random-access memory (RAM). That is, the process of locating a word within the storage array involves giving its address. The time needed to retrieve the word remains the same irrespective of the physical location of the word in the array. However, many data processing applications require searching items in some data structure, such as a table, stored in the memory. The established procedure to search a table is: 1) to store all the items where they can be accessed in sequence; 2) choose a sequence of addresses; 3) read the contents of memory at each address, and 4) compare the information read with the item being searched until a match occurs. This is exorbitantly time-consuming if the table is very large and/or the search algorithm is relatively inefficient. This time can be significantly reduced if the stored data can be identified for access by the content of the data itself rather than by an address. A memory unit accessed by content is called an associative memory or content addressable memory (CAM). This type of memory is accessed simultaneously and in parallel on the basis of the data content. This paper addresses the question: Is content addressability better than random-accessibility?     

基于用户行为分析的视频推荐算法研究

视频推荐属于互联网推荐系统的应用之一,传统的互联网推荐技术中,协同过滤技术是应用最多和最广泛的.但是区别于其他内容的推荐,(如文本信息、音乐、Web网页以及电子商务领域的推荐等)视频内容的数据量偏大,在推荐的时效性上存在很大的缺陷.较大的视频数据使得算法的时间和空间复杂度较大,推荐效果不佳.根据这一特点,提出了一种基于用户行为信息分析的视频推荐.该方法充分挖掘用户行为信息,以用户行为信息代替视频内容大数据作为推荐的数据集,可以将用户可能感兴趣的视频内容主动推送给用户.实验结果也验证了文中提出的方法的有效性和高效性.     

基于数据挖掘的风电功率预测特征选择方法

输入特征向量的选择是建立风电功率预测模型中至关重要的第一步,但由于风电机组的待选监测量项目过多、部分监测量与风电功率的相关性不明显甚至不相关、信息冗余量大等因素造成输入向量集的选取不够合理,进一步影响功率预测模型的准确性。针对这一问题,在综合对比研究了邻域粗糙集、随机森林和互信息这三种较为有效的用于特征选择的数据挖掘算法的基础上,提出了一种综合性能较好的基于随机森林筛选风电功率预测模型输入向量的方法,并分析了另两种方法的特点和适用范围,最后使用风机的实际运行数据,基于最小二乘支持向量回归算法对文中所提出的方法进行了验证。仿真结果表明,该方法能够通过减少功率预测模型的输入向量有效地降低模型复杂度,不仅加快了模型的预测速度而且提高了预测的精度。     

Dynamic optimal route search algorithm for car navigation systems with preferences by dynamic programming

Optimal route search to the destination is one of the most important functions of car navigation devices. The development of road traffic infrastructure has made it possible to receive real‐time information of the traffic situation. Route search algorithms for car navigation devices make use of this information to avoid the traffic congestions. Such algorithms should find the new optimal route efficiently when the traffic situation changes. Usually, the minimum traveling time or distance is considered to define the optimal route. However, the minimum traveling time or distance is not always what the user is looking for. The user may prefer to travel on a certain route even at the cost of traveling time or distance. Car navigation devices should consider such preferences when finding the optimal route. In this paper, we propose a dynamic programming algorithm to find the optimal route considering that it should deal with the changes of the traffic situation and multiple criteria. The proposed method uses the information from the previous computation to find the new optimal route considering user preferences when the traveling time of the road section changes. The proposed method was applied to a real road network to find the optimal route. Results show that the proposed method can find the user‐preferred optimal route. Simulation results also show better calculation time of the proposed method compared to the Dijkstra algorithm. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

考虑多源信息实时交互和用户后悔心理的电动汽车充电负荷预测

文章提出了一种考虑多源信息实时交互和用户后悔心理的电动汽车充电负荷预测方法。首先,通过出行链理论和起止点(origin-destination,OD)矩阵法分别获得私家车和出租车出行的起讫点,利用Dijistra算法规划行驶路径;然后,构建基于路网实时车流量统计的速度-流量实用模型,计算路网各路段实时车速。构建考虑环境温度和车速的电动汽车单位里程耗电量模型,计算耗电量;接着考虑充电电价、时间、沿途耗电量等因素,提出基于后悔理论的电动汽车用户充电站选择模型;随后基于交通路网、车辆、公共快充站以及配电网等多源信息,建立多源信息实时交互的电动汽车充电负荷预测框架。最后采用蒙特卡洛法模拟了私家车和出租车的出行和充电过程,得到了区域内充电负荷时空分布。以某区域交通路网和典型配电网为例进行仿真,验证了所提充电负荷预测方法的有效性。仿真结果表明多源信息的及时交互以及考虑用户的后悔心理,会对充电负荷的时空分布产生影响。     

基于多源信息和遗传算法的配电网故障定位模型

准确地定位配电网的故障区段对于用户供电可靠性有十分重大的意义。目前所提出的配电网故障定位算法有一定的局限性,当信号发生畸变时,很容易出现误判,导致无法快速准确定位到故障区段。针对现有算法的局限性,考虑增加信息多源性,在遗传算法的基础上引入低压侧用户信息,构建了一个高鲁棒性的故障定位模型。通过算例仿真分析,最终证明了该算法相比于不考虑低压侧用户停电信息的算法具有更高的准确性,更加适用于实际工程。     

基于IABC和聚类优化RBF神经网络的电力信息网络安全态势评估

为提高电力信息网络安全态势评估的精度,提出一种基于改进人工蜂群（IABC）算法和密度峰值聚类（DPC）算法优化径向基函数（RBF）神经网络的电力信息网络安全态势评估方法。首先,引入改进密度峰值聚类（IDPC）算法对人工蜂群（ABC）算法的种群空间多样性进行聚类分析,重新定义个体更新机制以提高算法的全局搜索能力。然后,构建分类RBF神经网络安全态势评估模型,利用IDPC算法对输入指标数据进行聚类分析,采用IABC算法对分类拓扑结构和参数学习过程进行优化,得到输入评估指标与输出安全态势值的最佳映射关系。最后,通过实例仿真证明所提方法的有效性。     

计及用户综合用能行为和政策导向的广域综合能源系统联合规划方法

针对日益加深的能源环境问题,从更大范围的宏观角度来研究综合能源系统规划具有重要意义。提出一种计及用户综合用能行为和政策导向的广域综合能源系统规划方法。首先,建立用户用能决策的效用模型。然后,分别构建综合能源系统中各类市场主体的规划收益模型。同时考虑供能改造的环境效益,建立政府对供需双侧污染排放的评估模型。在此基础上,基于不同主体间的博弈机理分析,构建面向广域综合能源系统的双层动态博弈规划模型。最后,利用迭代搜索法对模型进行求解。仿真结果验证了该方法的正确性和有效性。     

非线性负荷谐波贡献畸变功率评估指标与方法

以谐波电压或谐波电流为依据的现有谐波贡献度评估指标对电网侧和用户侧阻抗参数敏感,对特定情况有效,但普适性不强。针对这一问题,从电力系统是电能量转换和传输系统的实质出发,研究电压或电流畸变条件下电功率流的物理机制。基于坡印廷矢量分析法,比较现有不同畸变功率的定义,提出一种基于非基波视在功率的多谐波源贡献度量化指标,并结合电流矢量法进行了求解算法研究。通过理论仿真和实验测试,并与传统的电压、电流指标评估结果进行比较,证明了所提贡献度评估指标的合理性和可行性。     

Getting agents to help with the research

Intelligent agents are software programs that act on behalf of human users or other systems to carry out arduous information gathering and processing tasks. Thus, an agent-oriented approach is well suited for helping "a human" to find needed information on the Internet. This article describes the design of a multi-agent system and its cooperation with existing search engines. The proposed system is set up as a middle-layer agent between the user and the search engines. This system tracks the users activity and creates a pattern using association-rule mining as a text categorization technique. Depending on how well this pattern is drawn, the system provides more reliable, accurate and well-organized results for the user than if the user goes it alone. This system is in its initial implementation phase. We believe that it is a step towards a complete multi-agent based system for searching on the Internet.     

谐波污染用户建模及危害评估

评估谐波污染用户危害及治理效果,首先需要建立合理的用户谐波污染模型,再从监测数据辨识模型参数,进而建立合适的危害评估场景,定义并计算谐波污染指标,最后评价用户对电网的谐波注入污染程度。文中论述了目前各种谐波污染用户模型的基本原理和特点,归纳了现有评估谐波污染的方法,分析指出了各种模型的适用性和各种方法的优缺点,并通过仿真比较分析了各种评估方法。     

Exploiting opinion distribution for topic recommendation in Twitter

The popular social networking service Twitter provides rapidly updated information and online trends, which enriches and benefits people's daily life. At the same time, how to find out the really interesting and relevant topics from the massive streams of tweets, to provide precise topic recommendation for users, becomes a challenging problem in the real world. Previous collaborative filtering methods give solutions to traditional recommendation tasks considering users' positive reviews to help recommend items. However, to the problem ‘what is interesting to whom’ in Twitter, positive opinions toward a topic do not imply that the user will be interested in it with high probability, for the user probably prefers to know those controversial topics or hot events with a large number of negative posts. In this paper, we exploit the characteristics of topical opinion distribution for improving the performance of recommendation. The experimental results on a real‐world Twitter dataset show that the proposed opinion‐distribution‐aware topic recommendation (ODA‐TR) approach outperforms the state‐of‐the‐art collaborative recommendation methods. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Heuristic rule-based phase balancing of distribution systems by considering customer load patterns

In this paper, a heuristic backtracking search algorithm is proposed to adjust the phasing arrangement of primary feeders and laterals for phase balancing of distribution systems. The phase unbalance index of distribution feeders is calculated based on the phasing current magnitude of each line segment and branch, which has been solved by a three-phase load flow program. The database of an automated mapping/facility management (AM/FM) system is used to retrieve the component attributes, and the topology process is executed to determine the electrical network configuration and the customers served by each distribution transformer. By using the monthly energy consumption of customers in customer information system (CIS) and the typical daily load patterns of customer classes, the hourly loading profiles of distribution transformers and service zones can be derived to solve the individual phase loadings of each primary feeder and lateral. The phase balancing of distribution systems is enhanced by heuristic rule-based searching process to minimize the phase unbalance index. To demonstrate the effectiveness of proposed methodology, a practical distribution feeder with 2754 customers is selected for computer simulation to enhance three-phase balancing of distribution systems. It is concluded that three-phase balancing of distribution systems can be obtained by considering customer load characteristics.     

基于电路等效变换的二极管箝位式模块化多电平换流器电磁暂态并行仿真模型

针对模块化多电平换流器（modular multilevel converter,MMC）常规电磁暂态仿真模型计算资源消耗较大的问题,基于电路等效变换原理,提出了二极管箝位式模块化多电平换流器电磁暂态仿真的并行等效模型。首先将换流器子模块等效为受控源,实现子模块与换流器主电路的解耦,便于应用并行计算方法;其次根据子模块电路结构预先分析出各种可能的工作模式,以避免开关动作时重新生成计算矩阵,便于根据桥臂电流与开关状态等信息实时计算出模块端口电压。对一个12电平MMC换流器的仿真结果,验证了所提方法的有效性以及该等效模型的正确性。