电力光缆现状及展望

ADSS光缆和OPGW光缆是当前电力通信系统普遍使用的两种特殊的电力光缆，在对中国电力光缆目前使用和规划情况进行概述的基础上，总结了这些常用光缆的特性，同时介绍了我国在电力光缆生产、研究和产品标准制定等情况，最后对电力光缆的发展提出了具体希望。     

Thermal modeling of portable power cables

The US Bureau of Mines investigated the performance of portable power cables under time-varying load conditions. This research had a twofold purpose: (1) to define the thermal characteristics of electrically overloaded trailing cables; and (2) to construct a thermal model for cables to predict cable temperature rises resulting from load currents. Several tasks were undertaken in support of these goals during the three-year research effort. Overload tests ranging from 2 to 12 times rated ampacity were conducted in the Pittsburgh Research Center's Mine Electrical Laboratory. A thermal model of energized type G-GC trailing cables was constructed based upon empirical data from the US Bureau of Mines load tests. This model was then incorporated into an interactive computer program that can assist designers and approvers of mining machines in selecting the appropriate size trailing cable. This program can be the basis for a cable protection system which ensures that cables are not the source of fires, ignitions, burns, or explosions underground     

Insulation coordination of MV power cables

In medium voltage power cables, the concept of cost/reliability has been current since the end of the 1980s when the Brazilian Standards introduced ethylene-propylene-rubber (EPR) insulated cables, with different thicknesses of insulation for conventional cables and for those with blocked conductors or with water tightness constructions. However, despite the benefits obtainable by use of such cables, they have had limited use by electrical power utilities; perhaps because the concept has not become widely recognized. This paper intends to clarify and submit a new approach for design of the dielectric system of medium voltage cables, for use in underground and insulated overhead distribution feeders. Theoretical aspects of sizing the dielectric system, by means of coordinating the insulation, and also using reliability parameters, is dealt with in the paper. Results of practical applications are also presented and discussed     

Thermal performance of underground power cables with constant andcyclic currents in presence of moisture migration in the surroundingsoil

A numerical methodology for thermal analysis of buried power cables in presence of heat and moisture migration in the surrounding soil is presented. The governing equations are solved via a finite volume methodology and both cable and soil are incorporated in the problem formulation. The developed program is versatile and user-friendly, and was implemented in a personal computer. Results are presented for constant and cyclic loads, stressing the importance of moisture migration in power cable design     

Retrofitting-new high voltage XLPE cables substitutingpaper-insulated power cables in steel pipes

Many utilities still have paper-insulated pipe type cables in service. In the near future they may have to replace some of these systems due to local increases in electric power demand or aged cable insulation. In many cases the steel pipes are well protected against corrosion and thus suitable for further use. For retrofitting in such installations, XLPE-insulated cables offer several advantages. Felten & Guilleaume Energietechnik AG has developed a new three-core XLPE-insulated 64/110 kV cable with reduced insulation thickness (10 mm), that can be pulled into a pipe. In co-operation with VEW ENERGIE AG, the cable performance is being investigated in a field test, that started in October 1996. This long-term loading cycle test will last for three years. The test voltage, applied between conductor and earth, amounts to 127 kV. The temperature is measured with the help of an optical-fiber measurement system. This device is computer controlled and works as a remote monitoring system     

电力电缆讲座 第一讲 电缆的结构和特性(上)

我国城市电网中 ,电力电缆的应用越来越广泛。近年来 ,一些大中城市加快了城网建设改造的步伐 ,在 1 1 0 k V及以下供配电系统大力建设和发展电缆网 ,特别是在城市中心区段 ,结合市政改造积极采用电缆供电 ,并有条件地进行“电线入地”。随着城网电缆化比例的提高 ,城市供配电网的供电可靠性也相应提高了。为此 ,本刊特请作者撰写《电力电缆》讲座 ,重点介绍 1 1 0 k V及以下电缆应用技术方面的一些有关问题。其中包括电缆的结构和特性、电缆敷设、接头安装、电缆试验及故障测寻和电缆运行管理等专题。供从事供配电电缆规划设计、施工安装及运行检修的人员参考。全文共五讲 ,分六期刊出。     

Classification of superconducting cables of power purpose

Classification of low-temperature and high-temperature superconducting cables of direct and alternating current for power purposes based on the traditional and prospective implementation is presented. Results of designing multicore superconducting cables with localized magnetic field, providing maximal critical current density, reducing consumption of superconducting material, cold fluid, and energy losses in cables are reported.     

Ampacities of power cables wound on reels

This paper presents a mathematical model that is capable of calculating the ampacity of a wide variety of power cable designs consisting of an arbitrary number of layers on a cable reel. The model considers round cables with copper conductors. The validity and accuracy of the ampacity model were verified by comparing the predicted temperature distribution within the reel with measured temperatures collected during an extensive testing program conducted at the US Bureau of Mines (USBM). The mathematical model predicted a temperature distribution within the cable layers that was very close to the measured variation in temperature. The value of the program is illustrated by calculating ampacities for several copper conductor sizes     

基于热电耦合的10kV XLPE地下电缆群温度场数值计算

利用有限元计算了地下电缆的焦耳损耗和温度场分布,利用迭代法实现地下电缆温度场和电磁场间的耦合计算,提高了地下电缆温度场计算的精度,利用迭代法确定地下电缆的载流量。本文对地下直埋多芯电缆群的温度场进行了计算,并给出了相应的载流量。耦合计算结果比非耦合计算结果更接近试验结果,完全满足工程实际的需要。     

High voltage VLF testing of power cables

This publication describes a laboratory test program conducted with the objective to develop a test that would replace the existing DC withstand test. The article describes the methodology used to establish the voltage duration and magnitude of VLF (0.1 Hz) high voltage field tests suitable for crosslinked polyethylene (XLPE) insulated power cable. The results show that the voltage breakdown of laboratory aged XLPE cable at 0.1 Hz is approximately equal to that at 60 Hz, that proof tests at 0.1 Hz cause very little damage to the cable, and that 0.1 Hz testing appears to be a satisfactory alternate to DC testing. Preliminary values are suggested for voltage magnitude and time duration of cable acceptance, maintenance and proof tests at 0.1 Hz for XLPE cable rated up to 35 kV. A program is underway to similarly evaluate samples of service-aged XLPE cable; as well as to demonstrate the use of the preliminary test values at typical utility installations     

SZ绞在电力电缆制造中的应用

介绍了国外SZ绞已在电力电缆制造中广泛地应用情况,这种结构型式具有众多优点,它有利于增加电缆的制造长度,提高生产效率,节省大量的能耗和材料,可省去了巨大的绞笼等设备,值得我国电力电缆制造行业应用和推广。     

电力电缆的现场试验与诊断

本文介绍电力电缆现场试验和诊断的现状和发展。直流电压试验作为一种对油浸纸绝缘电缆非常有效的方法应用至今 ,但它对塑料绝缘电缆是无效而且有害的。文中讨论了近几年以来开发的 0 .1Hz VL F法、CDA法、OWTS法以及变频谐振试验系统。用变频谐振试验系统进行的 2 0～ 30 0 Hz交流电压试验已被 IEC确认为高压和超高电力电缆的主要试验方法。     

Evaluation of materials for WTR-insulated power cables

In order to improve the resistance to water treeing of standard crosslinked polyethylene (XLPE) insulation used in medium voltage power cables, a number of materials were selected and studied that represent different water tree growth prevention strategies: (a) using materials with crystallinity and morphology different from that of XLPE, or (b) using additives modifying the interaction between water and materials. Two laboratory procedures were adopted that assess the water tree resistance performance of the materials through different criteria: one based on divergent field geometry (CNRS) and another based on uniform field geometry (Pirelli). Both tests are shown to be complementary in their prediction of the performance of the selected water tree resistant materials. The work reveals a specific additive that greatly increases the water tree resistance performance of the insulation in different polymeric matrices     

单芯钢丝铠装电力电缆铠装结构的探讨

单芯钢丝铠装电力电缆的铠装损耗 ,影响了电缆载流量 ,这问题已越来越引起人们的关注 ,它的应用已经给某些输电工程带来了不小麻烦和经济损失。本文通过试验和查阅有关文献 ,对铠装钢丝的损耗等问题进行了深入探讨 ,并提出采用铜丝来隔磁是个错误概念。这种结构的钢丝仍然会产生磁滞和涡流损耗 ,并使载流量下降。最后 ,提出了应修改有关产品标准 ,并提示用户要慎重选用单芯钢丝铠装电力电缆     

High-voltage testing of medium-voltage shielded power cables

Medium-voltage power cables rated 2001-35000 V are tested using both 60 Hz AC voltage and DC voltage before leaving the cable manufacturing plant. Shielded medium-voltage cables are also required to meet the corona extinction level voltage established. These shielded cables are to be free of partial discharge at voltages well above operating voltages. In addition to these factory tests, the user normally requires a DC high-potential test after installation and sometimes a test is required when the cable is still on the reel. These various tests are also discussed     

我国电力光缆应用和市场的发展及问题

追溯了我国电力光缆应用的发展过程，讨论了在市场和产业的形成、发展中所出现的问题。     

The finite elements method in unbounded temperature field of power cables

Contents Extension of the finite elements method to unbounded field presented in previous works has been reviewed. The approach most suitable for temperature field of underground power line has been choosen. The adequate computer program has been developed and tested for steady state problem of line source in uniform earth for which exact solution exists. The program ensures satisfying accuracy of computation despite division with finite elements of a much smaller area than in previous works. It was observed that exact solution is located always between that given with the Dirichlet's and the Neumann's condition at boundary in earth. Moreover several numerical experiments confirmed that arithmetic mean of these two solutions converges to the exact one.

---

Die Finite Elemente Methode im unendlichen Temperaturfeld des Starkstromkabels

Übersicht Die Anwendung der Finite Elemente Methode in unendlich ausgedehnten Gebieten wurde bereits in anderen Veröffentlichungen behandelt. Der vorliegende Beitrag gibt eine Übersicht und wählt die für die Berechnung des Temperaturfeldes eines Starkstromkabels günstigste Methode aus.—Die Überprüfung des Programmes am statischen Feld der Linienquelle im homogenen Erdboden mit der bekannten analytischen Lösung liefert eine gute Übereinstimmung, obwohl ein viel kleineres Gebiet als in den früheren Aufsätzen zu Grunde gelegt wurde. — Es wurde bemerkt, daß die richtige Lösung zwischen den Ergebnissen liegt, die man durch Anwendung der Disichlet'schen und Neumann'schen Randbedingung im Erdboden erhält. Numerische Experimente haben gezeigt, daß das arithmetische Mittel dieser beiden Ergebnisse gegen die richtige Lösung konvergiert.

     

High-voltage power cables plug into the future

The four dominant types of high-voltage transmission cable -paper insulated oil filled (OF), cross-linked polyethylene insulated, oil filled, gas insulated, and high-temperature superconducting - offer a variety of advantages, disadvantages, and potential for future development. So does an emerging technology, high-temperature superconducting cable. This article examines them all and assesses their position in the new world of high-voltage underground transmission.     

发电厂电缆防火措施探讨

做好发电厂内电缆防火、防止电缆火灾引发重大事故是一个实际而又重大的课题。为此,针对电厂电缆火灾事故时有发生的情况,简述了目前发电厂电缆防火的主要措施,并以广东省某电厂9号机组电缆事故的防范为例,详细介绍了其电缆防火的措施,这些措施对其它电厂有一定的参考价值。     

Rating power cables in wrapped cable trays

Conductor temperatures for a given ampacity loading is a function of ambient temperature inside the tray. In other words, the ampacity of cables included in these tray systems has to be rated at the ambient temperature inside the tray. Cable overheating and eventual failure can result if cables are overloaded or not derated for operation. IPCEA Pub. No. 54-440/WC lists cable ampacities in air ambient temperature of 40°C. Cables operating at temperatures above this have to be derated accordingly. An algorithm is presented for determining ambient temperatures in the cable tray for conditions of natural air convection with different cable loading. Hence, derated cable ampacities can be derived from those at 40°C. Although at present, there is no industry standard for wrapped cable trays, the method used here can be used to develop such a standard