Distance-differential protection of transmission lines connected to wind farms

Distance relays are often used in the protection of the transmission lines connected to the wind farms. The distance relay using the transmission line impedance measurement identifies the type and location of the fault. However any other factors that cause the failure of the measured impedance, makes the relay detect the fault in incorrect location or do not detect the fault at all. One of these factors is the fault resistance which directly increases the measured impedance by the relay. One of the methods to eliminate relay under-reach effect is using of the trip boundaries. Trip boundaries are changing with wind variation and following with output power of the wind farms. Therefore, trip boundaries should continuously change proportional by the wind speed. In this paper, a method is provided based on the combination of distance and differential protection. In this method, using active power calculation in both ends of the transmission line, fault resistance is calculated and its effects are directly deducted from the calculated impedance by the relay. Therefore, variable trip boundaries are not needed anymore. Also in this method, unlike the technique that the trip boundaries are used, the exact location of fault and its distance from the relay also is calculated. Detailed model of a doubly-fed induction generator (DFIG) driven by a wind turbine is used in the modelling. Results of studies show that the presented method eliminates properly the mal-operation of relays under all different fault resistance conditions.     

LTb电梯系统运行参数分析及工程应用

LTb电梯是在高层建筑物中新近开始研究和应用的一种新梯种．有广阔应用前景。本文对LTb电梯系统运行参数在大楼各层相同和各层不同条件下．用统计分析方法分别证明了其可能停站概率忍用单轿厢可能停站数fi和服务楼层数n的表示公式,并进一步提出和证明了用轿厢乘客人数r和服务楼层数n表示的公式;阐述了上述公式的工程应用;并给出了LTb电梯和其他多轿厢电梯的的使用比较例。     

Optimal allocation for electric vehicle charging stations using Trip Success Ratio

This paper proposes a new model for optimally allocating Plug–in Electric Vehicle (PEV) Charging Stations (CSs) in the network. The model considers Trip Success Ratio (TSR) in order to enhance CS accessibility for PEV drivers. Diversity of usage and different driving habits are considered in the presented model, as well as different trip types (In-city, Highway). The allocation model has two stages: modeling TSR to estimate Charging Station Service Range (CSSR), and the CS allocation stage. In the first stage, the service range of charging stations has been estimated using TSR with consideration of the uncertainty of trip distances (In-city, Highway) and the uncertainty in the Remaining Electric Range (RER) of PEVs. The estimated CSSR is utilized in the CS allocation stage in order to optimize the CS location set that covers the network with a certain guaranteed TSR level. The allocation problem has been formulated as the Maximum Covering Location Problem (MCLP) in order to make the optimal decision for allocating CSs in the network.     

A Co-Point Mapping-Based Approach to Drivable Area Detection for Self-Driving Cars

The randomness and complexity of urban traffic scenes make it a difficult task for self-driving cars to detect drivable areas. Inspired by human driving behaviors, we propose a novel method of drivable area detection for self-driving cars based on fusing pixel information from a monocular camera with spatial information from a light detection and ranging (LIDAR) scanner. Similar to the bijection of collineation, a new concept called co-point mapping, which is a bijection that maps points from the LIDAR scanner to points on the edge of the image segmentation, is introduced in the proposed method. Our method positions candidate drivable areas through self-learning models based on the initial drivable areas that are obtained by fusing obstacle information with superpixels. In addition, a fusion of four features is applied in order to achieve a more robust performance. In particular, a feature called drivable degree (DD) is proposed to characterize the drivable degree of the LIDAR points. After the initial drivable area is characterized by the features obtained through self-learning, a Bayesian framework is utilized to calculate the final probability map of the drivable area. Our approach introduces no common hypothesis and requires no training steps; yet it yields a state-of-art performance when tested on the ROAD-KITTI benchmark. Experimental results demonstrate that the proposed method is a general and efficient approach for detecting drivable area.     

基于OREMS的核电厂址撤离时间估计

为了更好地制定核电厂应急计划,指导可能的公众应急撤离事件,根据我国关于核电厂应急撤离的法规,参考美国NRC和其他国家对核电厂址撤离时间估计（ETE）的要求,结合我国基本国情,提出适合我国核电厂ETE的基本方法。采用NRC推荐的OREMS宏观交通模拟软件计算ETE的通行时间,对国内某内陆核电厂址进行实例计算,并根据计算结...     

600MW机组锅炉灭火不停机操作优化

针对宁夏大唐国际大坝发电有限责任公司2×600 MW火电机组设备状况,总结了锅炉灭火后的操作方法,对锅炉灭火后不停机的可行性进行了讨论,并提出了优化建议。     

基于网络日志内容分析的自驾游时空行为研究 ——以陕西汉中市为例

本文以陕西汉中市为研究案例,通 过网络日志采集市域范围内的自驾游出行信 息,并采用数据挖掘方式对自驾游时空行为进 行分析。结果表明：一、来汉中市自驾游的出 游时间集中在4月和10月,平均逗留时间为2.098 天,日均访问节点个数为1.80个,以短途、短时 观光出游为主,具有长时维度的季相模式和 短时维度的周末模式;二、在区域自驾游空间 结构方面,形成游憩点轴—闭环模式,表现为 来汉中自驾游游客的客源地呈近域集中特征, 游客来自西安市方向的特征显著,自驾旅游流 线和路径以高等级道路为主骨架,来汉中市自 驾游以西汉高速和G108为主体交通廊道,辐 射周边国道和省道沿线;三、在内部自驾游空 间结构方面,形成城景放射—互动模式,汉中 市境内自驾游游客行为访问热点呈现高聚集 特征,以汉中市区、南郑县城和勉县县城周边 景区（点）为主,辐射带动围绕城市和景区近 邻集群区域;四、结合旅游时空行为的发生机 制,发现来汉中自驾旅游时空行为以时间规 限、交通指向、设施贴近、营销刺激四大机制 影响其形成和组织。     

基于物联网技术的城市交通出行管理与服务体系研究

随着城市人口的增多和汽车数量的持续增加,交通堵塞现象日趋严重,由此引发了环境噪声、大气污染、能源消耗等严峻问题,为解决这些问题可从源头上进行思考。城市交通出行问题作为源头上的重要交通事件,对其进行深入研究、合理引导,将能有效改善城市交通问题。该文对交通出行的制约因素及其解决方法进行了综合分析,提出了基于物联网技术的交通出行解决方案,建立了面向交通出行管理与服务模型框架体系,通过对制约交通出行因素信息的全面采集,综合分析,实现对交通参与者的实时诱导与服务,从而提高公安机关交通管理与服务水平。     

Trip to IEC

正For long impressed by the time-cherished IEC,I have been inspired to learn more about this international organization since my first interview with Mr.James Matthews III,the Vice-President of IEC in March 2012,which was followed by several more important interviews with IEC senior officers including former IEC President Dr.Klaus Wucherer,IEC Vice-President Shu Yinbiao and IEC General SecretaryCEO Frans Vreeswijk.I was really looking forward to visiting and exploring the IEC someday by myself.     

FSSS在镇海发电有限公司200MW机组DCS改造中的应用

介绍了浙江镇海发电有限公司200MW火电机组热控DCS改造中的基于北京和利时公司MACS系统进行组态的炉膛安全监察系统FSSS方案的改造和投运情况。把FSSS系统纳入了DCS可减少故障率，提高了FSSS系统的可靠性。