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Wavelet-based data compression for wide-area measurement data of oscillations

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Journal of Modern Power Systems and Clean Energy 2018年第6期6卷 1128-1140页

作者： Lin CHENG Xinchi JI Fang ZHANG He HUANG Song GAO State Key Laboratory of Control and Simulation of Power System and Generation Equipment Tsinghua University State Grid Jiangsu Electric Power Company

This paper proposes a wavelet-based data compression method to compress the recorded data of oscillations in power systems for wide-area measurement systems. Actual recorded oscillations and simulated oscillations are compressed and reconstructed by the waveletbased data compression method to select the best wavelet functions and decomposition scales according to the criterion of the minimum compression distortion composite index, for a balanced consideration of compression performance and reconstruction accuracy. Based on the selections, the relationship between the oscillation frequency and the corresponding optimal wavelet and scale is discussed, and a piecewise linear model of the base-2 logarithm of the frequency and the order of the wavelet is developed, in which different pieces represent different scales. As a result, the wavelet function and decomposition scale can be selected according to the oscillation frequency. Compared with the wavelet-based data compression method with a fixed wavelet scale for disturbance signals and the real-time data compression method based on exception compression and swing door trending for oscillations, the proposed method can provide high compression ratios and low distortion rates.

关键词： Data compression Oscillation Wavelet transform wide-area measurement system(WAMS)

Quasi-4-dimension ionospheric modeling and its application in PPP

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Satellite Navigation 2022年第3期3卷 207-220,I0005页

作者： Shengfeng Gu Chengkun Gan Chengpeng He Haixia Lyu Manuel Hernandez-Pajares Yidong Lou Jianghui Geng Qile Zhao GNSS Research Center Wuhan University129 Luoyu RoadWuhan430079China Hubei Luojia Laboratory Wuhan University129 Luoyu RoadWuhan430079China UPC-IonSAT/IEEC-UPC UPC Mod.C3 Campus Nord UPCc/Jordi Girona 1-3BarcelonaSpain

Ionospheric delay modeling is not only important for Global Navigation Satellite System(GNSS)based space weather study and monitoring,but also an efficient tool to speed up the convergence time of Precise Point Positioning(PPP).In this study,a novel model,denoted as Quasi-4-Dimension Ionospheric Modeling(Q4DIM)is proposed for wide-area high precision ionospheric delay correction.In Q4DIM,the Line Of Sight(LOS)ionospheric delays from a GNSS station network are divided into different clusters according to not only the location of latitude and longitude,but also satellite elevation and azimuth.Both Global Ionosphere Map(GIM)and Slant Ionospheric Delay(SID)models that are traditionally used for wide-area and regional ionospheric delay modeling,respectively,can be regarded as the special cases of Q4DIM by defining proper grids in latitude,longitude,elevation,and azimuth.Thus,Q4DIM presents a resilient model that is capable for both wide-area coverage and high precision.Four different sets of clusters are defined to illustrate the properties of Q4DIM based on 200 EUREF Permanent Network(EPN)stations.The results indicate that Q4DIM is compatible with the GIM products.Moreover,it is proved that by inducting the elevation and azimuth angle dependent residuals,the precision of the 2-dimensional GIM-like model,i.e.,Q4DIM 2-Dimensional(Q4DIM-2D),is improved from around 1.5 Total Electron Content Units(TECU)to better than 0.5 TECU.In addition,treating Q4DIM as a 4-dimensional matrix in latitude,longitude,elevation,and azimuth,whose sparsity is less than 5%,can result in its feasibility in a bandwidth-sensitive applications,e.g.,satellite-based Precising Point Positioning Real-Time Kinematic(PPP-RTK)service.Finally,the advantages of Q4DIM in PPP over the 2-dimensional models are demonstrated with the one month's data from 30 EPN stations in both high solar activity year 2014 and low solar activity year 2020.

关键词： Undifferenced and uncombined observation Ionosphere delay modeling PPP Design wide-area

Positioning with wide-area GNSS Networks: Concept and Application

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Positioning 2012年第1期3卷 1-6页

作者： Tarig A. Ali Department of Civil Engineering American University of Sharjah Sharjah United Arab Emirates

The use of Global Navigation Satellite Systems (GNSS) for positioning has revolutionized the way location data is be- ing collected. The NAVigation System with Time And Ranging Global Positioning System (GPS), which is a principal component of the global navigation satellite system (GNSS);is a satellite-based radio navigation system that provides positions of points of interest and time information to users. GPS positional accuracy can be improved by using differential corrections obtained through a technique called Differential GPS (DGPS), which is known to provide the most accurate positioning results. Differential correction can be applied in real time at the data collection phase or in the of- fice, at the post-processing phase. DGPS is generally used for positioning purposes through static or kinematics GPS surveys. In static GPS surveys, one receiver is placed at a point whose coordinates are known and the other receiver is placed over a point whose coordinates are desired. In kinematic surveys, one receiver remains at one point (base station) normally with known coordinates, and the other receiver (rover) moves from point to point in the project area. Kinematic surveys in which points positions are computed on-the-fly (OTF) are known as real-time kinematic (RTK). RTK surveys provide real-time locations of points of interest needed in many applications. Positioning with wide-area GNSS networks is basically based on the DGPS and RTK concepts. Observables from a network of a finite number of GPS receivers over an area are processed by a server at a central location (network server) and made available to the users of the network later or in real-time through radio-based, satellite, or wireless communications. This article provides a review of the concept and application of positioning with wide-area GNSS networks.

关键词： wide-area GNSS Network Virtual Reference Station (VRS)

Communication Networking Schemes for wide area Electric Vehicle Energy Service Network

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Energy and Power Engineering 2013年第4期5卷 1415-1420页

作者： Dequan Gao Jinping Cao Yiying Zhang Xiuli Wang 1Beijing University of Posts and Telecommunications Beijing 100876 China 2State Grid Information & Telecommunication Company Ltd. Beijing 100761 China China Electric Power Research Institute Beijing 100192 China Information Communication Branch of Beijing Electric Power Company Beijing 100031 China

Electric vehicles (EVs) are an emerging type of mobile intelligent power consumption devices in Smart Grid as new green transport tools. In order to provide a powerful automation and intelligence support for wide area electric vehicles energy service network, we analyze the network infrastructure and communications demands of various terminals, devices and monitoring systems distributed in wide area electric vehicle energy service network. According to interactive user services scenarios and energy operations intelligent monitoring, we propose multimode communication integration architecture for wide area electric vehicle energy service network by means of the fusion of the Internet of Things (IoT) technology. Then, we design different networking schemes in access networks and backbone transmission networks meeting multi-scene and multi-operation interaction requirements. The networking schemes will provide efficient technical support to implement intelligent, cross-regional, interactive energy services for electric vehicle users.

关键词： Electric Vehicle wide-area Energy Service Network Communication Networking Internet of Things

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强迫功率振荡源的在线定位分析技术

中国电机工程学报 2014年第34期34卷 6209-6215页

作者：王茂海孙昊国家电网华北电力调控分中心北京市西城区100053 国网新源控股有限公司北京市西城区100053

强迫功率振荡源的在线定位对电网安全稳定运行具有至关重要的作用。基于相量测量装置(phasor measurement unit,PMU)的实测数据和同步发电机转子运动方程,给出振荡过程中发电机机械输入功率波动的计算方法。通过对振荡过程中发电机机械... 详细信息

强迫功率振荡源的在线定位对电网安全稳定运行具有至关重要的作用。基于相量测量装置(phasor measurement unit,PMU)的实测数据和同步发电机转子运动方程,给出振荡过程中发电机机械输入功率波动的计算方法。通过对振荡过程中发电机机械输入功率波动、电气输出功率波动、转速(频率)波动的相位关系的理论分析,给出强迫功率振荡的在线监测分析方法。如果原动机不是强迫扰动源,发电机组因响应外界扰动而处于振荡过程中时,机械功率的波动相位滞后于电气功率的波动相位。由于引进PMU实测数据,所提方法可实现各个发电机组独立分析、相互解耦,避免了引入全网模型带来的分析误差和可靠性降低,减少了在线监测分析的复杂程度。实际算例表明,所提方法能有效判断同步发电机是否为强迫功率振荡源,为低频振荡的分析、控制提供可靠参考。

关键词：低频振荡强迫功率振荡在线定位广域测量系统 wide-area measurement system (WAMS)

基于相对增益和改进粒子群算法的PSS与直流调制协调策略

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中国电机工程学报 2014年第34期34卷 6177-6184页

作者：王曦李兴源赵睿四川大学电气信息学院四川省成都市610065

现有电力系统稳定器(power system stabilizer,PSS)和直流调制多使用本地信号作为控制器反馈输入信号,控制器间的交互作用可能降低甚至破坏系统稳定性。提出了一种基于广域测量信号的PSS与直流调制协调策略,首先通过留数法选择对于振荡... 详细信息

现有电力系统稳定器(power system stabilizer,PSS)和直流调制多使用本地信号作为控制器反馈输入信号,控制器间的交互作用可能降低甚至破坏系统稳定性。提出了一种基于广域测量信号的PSS与直流调制协调策略,首先通过留数法选择对于振荡模态可观性较强的广域信号作为阻尼控制器备选反馈信号;其次通过相对增益方法选择使PSS和直流调制交互影响最小的备选信号作为最佳反馈信号;而后设计分散控制器,并运用基于混沌和差分进化的混合粒子群优化算法对PSS和直流调制控制器参数进行协调优化。最后,通过EPRI 36节点系统仿真验证了协调策略的正确性和有效性。

关键词：协调控制广域测量系统相对增益混沌和差分进化的混合粒子群反馈信号 wide-area measurement system (WAMS) chaos and differential evolution particle swarm optimization algorithm (CDEHPSO)

多时滞广域测量电力系统稳定分析与协调控制器设计

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电工技术学报 2014年第2期29卷 279-289页

作者：古丽扎提.海拉提王杰上海交通大学电子信息与电气工程学院上海200240

根据电力系统存在时滞的差异性,将控制器信号分为本地无时滞控制输入信号和广域异地多时滞控制输入信号两部分,建立了多时滞电力系统的模型。运用Lyapunov-Krasovskii泛函理论推导出了含有时滞分量的线性多时滞电力系统稳定判据,将控制... 详细信息

根据电力系统存在时滞的差异性,将控制器信号分为本地无时滞控制输入信号和广域异地多时滞控制输入信号两部分,建立了多时滞电力系统的模型。运用Lyapunov-Krasovskii泛函理论推导出了含有时滞分量的线性多时滞电力系统稳定判据,将控制问题转换为线性矩阵不等式的可行性问题,并采用模型降阶方法对原系统进行降阶,实现了含有多个时滞的广域输出反馈控制,并计算出了能够使闭环电力系统稳定的最大时滞时间。讨论了系统稳定判据中时滞分量与广域控制器参数之间的关系,以及对区域间振荡的控制效果。最后以两区域四机系统为例,用时域仿真的结果说明了本文所提出的多时滞控制方法的有效性。

关键词：电力系统广域测量系统多时滞输出反馈控制器线性矩阵不等式时滞分量 wide-area measurement system(WAMS) linear matrix inequality(LMI)

A Fundamental Study on Multi-agent Pedestrian Model Based on Risk Avoidance Behavior during Road Blockage and Evacuation Simulation of Regional Urban Disaster

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Journal of Civil Engineering and Architecture 2019年第4期13卷 219-237页

作者： Hideaki Takayanagi Tatsuto Kihara Yosuke Kurita Kazuhide Kawaguchi Hidetoshi Kawaguchi Takaaki Furukawa Takuhi Ono Shogo Yamada Department of Urban Life Studies Tokyo City UniversityTokyo 158-8586Japan General Design Planning KIHARA Tokyo157-0067Japan Chuo Fukken Consultants co. LTD.Osaka533-0033Japan The Graduate of Environmental and Information Tokyo202-0006Japan

Regional cities in Japan are at the risk of experiencing big fire accidents or earthquakes every day.However,neither the number nor the capacity of shelters has increased because local governments might not consider them owing to budget shortfall.By contrast,wide-area evacuation simulations can easily provide an antagonizing image of regional urban disasters.After a disaster,the city collapses and the evacuation routes are closed;consequently,evacuees feel anxious and they cannot move as usual.This anxiety behavior has not been considered in previous related studies and simulations.In this study,a wide-area evacuation simulation is developed;this model can not only calculate the possibility of blocking escape routes when the city is broken but also provide safe and more realistic evacuation plans before a disaster occurs by incorporating into the simulation the risk avoidance behaviors of evacuees from road blockage,such as“the route re-seeking behavior”and“the shelter re-selecting behavior”.

关键词： wide-area evacuation simulation multi-agent model risk avoidance behavior regional disaster prevention plan