Worldwide underground transmission cable practices

Underground transmission cables are a vital part of any power transmission system which means that the selection of a particular cable must be based upon many considerations ranging from the cost of losses to environmental concerns. The focus of this paper is on the design, selection and testing of power transmission cables within specific geographic regions. Design considerations on a regional basis includes temperature constraints, voltage and voltage stress limits, capacity and ampacity, backfill requirements, cooling and bonding. The material presented in this paper covers land based transmission cables only. Submarine cables, URD or UD cables are not included     

Series-impedance of underground transmission systems

A general solution for the magnetic field in the soil is developed that satisfies arbitrary boundary conditions on an underground cylindrical surface at a finite depth below an earth/air plane surface. A quasi-steady state hypothesis is assumed. The series impedance of an underground cable with a perfectly conducting sheath is evaluated taking into account skin effect in the soil. The numerical results are compared with F. Pollaczek's (1926) classical solution     

输变电设备的检修策略

针对当前检修定义混乱的情况,提出将检修过程分成检修策略层、检修安排层和检修具体实施层,检修策略主要是确定设备采取何种检修方式.论述三方面内容:一是明确检修策略与检修、检修方式和检修优化的关系;二是简要综述了检修策略的研究现状;最后提出了检修策略模型的建立过程.     

配电网网损分析与控制方法

针对中低压配电网的网损分析和运行优化,从理论线损计算方法、基于损耗最小化的运行优化措施和线损管理三方面对现有研究成果进行了综述和分析。因理论线损计算是配电网经济运行的基础,为此。重点综述了近几年理论线损计算方法所取得的最新研究进展,包括：针对传统线损算法的改进。改进前推回代法,最大网络流法的应用以及人工智能技术在中压配电网线损计算中的应用。同时从技术和管理两方面对线损控制措施进行了分析,指出了配电网经济运行和线损管理研究中有待解决的问题。     

输配电价改革之探讨

依据汕头电网以及国内外的实际资料．论述了输配电价改革是解决当前电网企业融资能力差、电网建设滞后等问题,使企业走上良性发展的必然选择。从电网企业目前的资产状况、投融资方式、成本核算、税收政策、输配电划分界面等方面,较为全面地分析了当前输配电价改革面临的问题,并有针对性地提出了解决问题的建议。     

Detection and location of dielectric fluid leaks on pipe-type cablesystems

The feasibility of using a hydrocarbon sensing wire to detect and accurately locate dielectric fluid leaks in power cables is shown. The construction of sensor cables developed for this purpose is described. The tests carried out on the cable are also described, and field trial results are reported. Because retrofitting old and operational feeders requires costly excavations, the system is suitable for installation on new feeders. However, use of boring techniques, which eliminate the disruption and expense of surface excavation by producing a small diameter tunnel beneath the surface, is an alternative option that is presently under investigation     

输变电设备在线监测装置的试验体系和项目

为了检验输变电设备在线监测系统的功能和可靠性,需要进行一系列试验.在总结在线监测系统的应用经验和参考相关标准的基础上,首次全面提出了试验体系包括型式试验、出厂试验、交接试验、特殊试验和抽样试验,以及包括准确度试验、模拟试验、绝缘试验、环境试验、电磁兼容试验、机械性能试验、连续通电试验和可靠性试验等试验项目的具体内容和指标要求.     

高温超导交流输电电缆导体层电流分布研究

本文通过对高温超导输电电缆导体各层电磁平衡方程组的建立,结合高温超导材料的电磁特性,提出影响导体各层电流均匀分布的相关结构参数关系表达式。通过对这些结构参数组合的调整,提出了使导体各层电流均匀的原则和方法。拟合及有详试验表明,本文的研究原则和方法是可行的。     

500 kV浏河-徐行输变电工程系统调试

500kV浏河-徐行输变电工程是上海电网由外部受电的第3条通道,对增加上海电网区外受电能力、满足地区用电增长有着重要的作用.为确保系统调试顺利进行,在设计、基建、调试、运行、调度等各个环节都加强管理,相关单位密切配合,落实了大量的组织和技术管理工作,并严格按照华东电网调试规范的要求,考核了各类新投运的500kV一、二次设备,为电网安全生产运行提供了重要技术依据.     

35 kV及以下输配电线路重要跨越改造

针对35 kV及以下线路重要跨越改造的特点,对采用搭设跨越架、专业跨越架工具、编织防护网等3种典型方式进行线路跨越改造工作进行阐述。并举例说明10 kV及以下线路重要跨越改造的典型措施。     

输配电设备在线监测系统的评价和选用

调查了国家电网公司中输配电设备在线监测系统的应用情况,包括在线监测系统的类型、数量及型号和制造厂家,以及被测设备的电压等级,总结了监测系统发现的输变电设备故障以及在线监测系统本身的故障.在调研基础上,对国家电网公司应用的在线监测系统进行了评价,并对输配电设备在线监测参数选用和输配电设备配置在线监测系统的原则提出了建议.     

提高输变电设施可用系数与状态维修

通过分析输变电设施的可靠性可用系数,将相关指标作为比较生产运行管理水平的一部分,指出科学实施输变电设施状态检修技术是进一步提高可靠性可用系数指标水平的重要途径之一,并提出设备经济成本、系统安全风险对更高指标适度性要求等方面的见解.     

New developments in systems for transmission and distribution substation control and protection

This paper contains the edited records of four presentations on Transmission and Distribution Substation Automation. These presentations were made at the 1980 Summer Power Meeting of the Power Engineering Society under the sponsorhip of the Application of New Technologies Working Group of the Automatic and Supervisory Systems Subcommittee of the PES Substations Committee. The organization and structure of transmission and distribution control and protection systems utilizing computer based technology are described in detail. The perspective of utility companies concerning the need and practicality of such systems is described. The problem of electromagnetic interference in transmission substations is also presented.     

高压地下电缆自适应继电保护方案的研究

针对电力电缆与架空线路电气参数的不同,分别从电力电缆分布电容以及零序阻抗两方面出发,提出了适用于高压地下电缆的自适应保护方案.通过对采用电容电流补偿和不采用电容电流补偿的分相电流差动保护的动作行为的比较分析,证明了电容电流补偿的必要性,提出了基于电容电流半补偿的分相电流差动保护方案.由于电缆线路零序阻抗非线性特性对保护性能产生很大的影响,精确计算电缆线路零序阻抗是非常必要的,故提出了基于迭代算法的自适应零序电流保护方案的思路与步骤.     

一种用于输电系统可靠性评估的软件TPLAN

介绍了输电系统可靠性评估软件TPLAN的结构及特点,TPLAN可以进行确定性事件分析、概率性事件分析、概率性切负荷评估和经济损失评估等.以概率性切负荷评估为例详细描述了TPLAN的可靠性评估过程.同时也对2009年丰大方式云南电网进行了可靠性评估.     

Multiconductor analysis of underground power transmission systems: EHV AC cables

It is widely ascertained that the multiconductor analysis is a powerful tool which can solve any structurally complex circuit (e.g., high-speed railway supply system, gas insulated lines, etc.). Moreover, this method can be also used as an in-depth analysis of the electric networks after the power-flow studies when they introduce simplifying hypotheses especially in the presence of asymmetry. In this paper, the multiconductor cell analysis has been applied to AC underground cable lines (UGC). This multiconductor procedure based on the use of admittance matrices, which account for the line cells (with earth return currents), different types of sheath bonding, possible multiple circuits, allows predicting the steady-state (and faulty) regime of any cable system. The method calculates the proportion and behavior of the phase currents carried by each parallel conductor, the circulating current in the sheath of each cable and the stray current in the earth. Moreover, some comparisons have been made with traditional programs showing the great accuracy of multiconductor cell model.     

EM-MWD系统无线传输技术探讨

本文从井下激励装置、无线传输信道、编码和调制以及地面接收四个方面探讨了电磁波随钻测量系统无线传输技术。指出国内的研究与实际应用存在一定的差距,并以俄罗斯ZTS电磁波随钻测量系统为例,分析了国外先进的井下无线传输技术。     

Development of fault point locating system for underground transmission lines using optical fiber current sensors

Fault point locating systems based on surge current detection have recently been used for fast recovery of underground transmission lines from faults. Electromagnetic induction type sensors have mainly been used for the detection of surge current. However, they are susceptible to electromagnetic noise which causes unstable system operation. To solve this problem, Tokyo Electric Power Co., Toko Electric Corporation, and Fujikura Ltd. jointly developed a new system using optical fiber current sensors. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 178(1): 21–28, 2012; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.20981