半导电橡皮与绝缘橡皮剥离性能的研究

<正> 一般6千伏及以上的中高压橡皮电力电缆,要求导电线芯和绝缘层表面均采用屏蔽层;此外为了安全起见,矿用电缆(如千伏级综合机械化采煤机组电缆)的绝缘层外需加一层屏蔽层;油井勘测电缆也要求在绝缘线     

一种风力发电用耐扭曲电力电缆

<正>国家知识产权局公布专利"一种风力发电用耐扭曲电力电缆",专利权人为福建南新电缆有限公司。本实用新型公开了一种风力发电用耐扭曲电力电缆,包括三相导电线芯和对应所诉三相导电线芯的三根地线芯。三相导电线芯呈品字形排列,导电线芯由导体沿径向由内向外依次包覆隔离层、内屏蔽层、绝缘层、外屏蔽层、外屏蔽包带层、编织屏蔽层、编织屏蔽层包带层,内屏蔽层、绝缘层和外屏蔽层同时一次完成挤包。三根地线芯置于三相导电线芯两两相切外侧,三相导电线芯和三根地线芯绞合构成缆芯,缆芯外依次包覆缆芯     

35kV交联电力电缆的常见故障及对策

分析了数起涉及线芯、主绝缘层、外半导电层、终端应力锥、屏蔽层外护套及绕包工艺中间模塑接头等位置的35kV电缆故障 ,发现故障原因系进水、屏蔽层腐蚀、主绝缘材料纯度不够、结构偏心、屏蔽层截面太小、外屏蔽料机械划痕、点压工艺不合理 ,绕包疏松及交联不充分所致。经采取技术革新、修订企业内部 35kV电缆订货要求、引进冷缩接头工艺等措施后 ,运行情况良好     

用于连续硫化生产线的测量技术

介绍了聚合物绝缘电缆在连续硫化生产线中的非接触式在线连续测量，这包括测量绝缘总厚度及偏心度的光学摄像系统；能高精度测量绝缘体中内半导电层、绝缘层及外半导电层厚度及偏心度的Ｘ射线测量系统。     

电缆高阻故障的查找

正1现场情况2014年7月,某钢铁企业在施工验收试验时发现,已敷设的YJV—8.7/10 kV 3×3 000 mm~2长1 090 m的电缆有故障。用兆欧表检测,红色和绿色电缆绝缘线芯对地绝缘电阻值均大于2 500 MΩ,黄色电缆绝缘线芯对铜带屏蔽层绝缘电阻值仅为10 MΩ,判断黄色电缆绝缘线芯对铜带屏蔽层发生高阻故障。我们通过三个步骤对故障进行查找:用HDM-15电缆故障定位电源将故障电缆烧穿,使     

化学交联三层共挤相邻规格导体换规不停车生产技术的浅析

交联聚乙烯中、高压电力电缆绝缘挤制多采用三层共挤连续交联型机组。这种型式的交联机组在挤制绝缘线芯(包括导体屏蔽、绝缘和绝缘屏蔽)时,每次变换导体规格就必须停机并更换挤出模具,这样就会将交联管内60~80 m长的绝缘线芯报废,而开机后又会浪费约150 m长绝缘线芯,浪费惊人。采用相邻规格导体不停机换模具而连续生产,这可以大大降低材料和能源的浪费,提高生产率,降低产品成本。     

对称数字通信电缆绝缘线芯在线检测和控制

随着通信与网络的飞速发展,对称数字通信电缆的需求增长很快。如何在这些电缆的制造过程中控制好产品质量,保证传输性能,已变得越来越重要。文中详细地介绍了对称数字电缆绝缘线芯生产过程中的在线检测控制系统,包括绝缘线芯外径、电容、偏心度和缺陷等测量与检测。     

中压交联电缆导体屏蔽内嵌问题的探讨

针对中压交联电缆导体屏蔽内嵌问题,从导体结构、设备影响因素、导体屏蔽材料的选取、三层共挤模具设计、绝缘线芯生产过程控制等方面分析了产生的原因并提出了解决的方法。     

中压电力电缆用半导电屏蔽料电阻率温度系数研究

中压电力电缆半导电屏蔽层的附加损耗与体积电阻率相关。电缆工作温度上升,半导电屏蔽层电阻增大,则电缆tg δ变大,半导电界面热效应变坏,影响电缆使用寿命,因此半导电屏蔽层电阻率的温度特性应平稳。相应的,半导电屏蔽层所用半导电屏蔽料的电阻率温度特性也应平稳。通过研究半导电屏蔽料的电阻率温度特性,认为通过考核电阻率的温度系数来评估半导电屏蔽材料的电气性能稳定性是一种可行且操作简便的试验方法,并给出了电气热稳定性较好屏蔽料的电阻率温度系数α范围。     

高压电缆半导电屏蔽料关键问题及研究进展

半导电屏蔽层作为高压电缆的重要组成部分,在电缆结构中起到均匀电场的作用。目前,我国高压电缆制造技术快速发展,然而高电压等级电缆料严重依赖进口,存在较多的技术壁垒。该文从高压电缆屏蔽料发展历程及关键问题、屏蔽料组成及关键性能参数、屏蔽料性能提升及改性3个方面综述了高压电缆屏蔽料的研究进展。首先,梳理高压电缆半导电屏蔽料发展历程,提炼当前屏蔽料面临的主要技术瓶颈和关键问题;其次,探讨屏蔽料导电和导热机理,从基体树脂、导电填充物和添加剂3个方面分析屏蔽料组成及性能,分析不同电压等级屏蔽料关键性能参数与技术要求;最后,探讨半导电屏蔽层配方,半导电屏蔽层–绝缘层界面特性和半导电屏蔽层性能对绝缘层电荷积聚特性的影响,并提出通过半导电屏蔽层改性抑制高压直流电缆绝缘层电荷积聚的方法。该文所做工作可为我国高压电缆半导电屏蔽料的研发、高压电缆性能评估提供理论参考。     

Smoothness evaluation of clean furnace blacks

The use of furnace process carbon blacks in semiconductive shields for cable is well known. For medium- to high-voltage power cables, furnace carbon black-filled semiconducting materials are used most notably to prevent a partial discharge at the surface between the conductor and the insulation or the insulation and the insulation shield layers. The author shows that two critical carbon black properties play a role in shield interface smoothness: dispersibility, and the amount of organic and inorganic residue present in the product     

屏蔽材料离子含量对抗水树XLPE电力电缆击穿特性的影响(英文)

Cable made with Dow HFDA-0587 BK,HFDB-4202 EC,and HFDA-0693 BK was found to meet DL/T 1070-2007 requirement of tree retardant XLPE(TR-XLPE) power cable.The alternate-current breakdown(ACBD) value after 360 days of accelerated water treeing test(AWTT) was 29 kV/mm,which exceeds the DL/T 1070-2007 requirement of at least 20 kV/mm.Cable made with semiconductive shield materials from other material suppliers and HFDB-4202 EC,however,failed to meet DL/T 1070-2007 requirement of at least 20 kV/mm after 360 days of AWTT.This failure to meet DL/T 1070-2007 requirement,apparently,was caused by the high content of ionic contaminants and ash levels in the semiconductive shield materials.The results in this report suggest the use of clean semiconductive shield materials is necessary,in conjunction with tree retardant insulation material,for cables to meet the higher performance TR-XLPE DL/T 1070-2007 requirement,which will enhance system reliability by extending cable life,while lowering life cycle costs.     

Technological progress in high-voltage XLPE power cables in Japan.I

The author reviews technological progress in the design and production of cross-linked polyethylene cable and discusses the present status of the products taking advantage of this technology. A brief historical background is given. The methods for determining or choosing cable characteristics, such as insulation thickness, service life, and cable quality, are discussed. Progress in production technology is discussed, covering improvements in polyethylene, three-layer common extrusion, dry curing, and smoothing of the semiconductive shield layers     

A study of electric stress enhancement. Part 2. Stress enhancement on semiconductive shields

For pt.I see ibid., vol.11 p.976-82, (2004).This paper evaluates the electric stress enhancement due to surface protrusions on the tape of semiconductive shield compounds used in power cables. The results of a conventional grade and a supersmooth grade shield compounds are reported. Using a laser-scanning instrument, the shape of protrusions on the tape surface of these compounds can be quantitatively determined. An algorithm is developed to portray the geometry of a protrusion so as to allow the calculation of its stress enhancement. First the supersmooth grade shield compound is illustrated as much smoother than the conventional shield compound. Besides exhibiting a lower number of protrusions, the surface protrusions on a supersmooth shield compound also are much "flatter" than those of the conventional shield compounds. Insulation thickness is confirmed to influence the stress enhancement and, consequently, different distributions of stress enhancement factor are observed with low voltage, say, 15 kV, and high voltage, say, 500 kV, applications. The conventional shield compound exhibits higher stress enhancement than the supersmooth grade compound in higher voltage cables, though the difference is much less with lower voltage settings. Since the total number of protrusions on the conventional shield surface is more than one order of magnitude higher, the supersmooth shield therefore can offer much better protection to a cable by minimizing the electric stress degradation in its insulation material.     

Stress controlling semiconductive shields in medium voltage powerdistribution cables

The construction of current extruded-dielectric, medium-voltage underground residential distribution (URD) cable is described, and requirements for semiconductive shields are examined. Conductor shields, insulation shields, semiconductive jackets, shields for high-voltage cables, and shields for rubber insulation are included. The composition of carbon black and polymer shields is discussed, and the mechanism of conduction in semiconductive shields are described. The historical development of shields is traced, starting with early types and covering developments in the 1970s, 1980s, and 1990s     

A study of electric stress enhancement. Part 1. Implication in power cable design

The increase in electric stress due to a surface protrusion at the interface between a semiconductive shield and a polymer insulation layer in power cables can lead to localized electron injection into the polymer insulation and result in undesired material degradation. This paper reports the analyses of electric stress enhancement of surface protrusions in several commonly encountered medium- and high-voltage power cable configurations. First, a brief review of the electric stress enhancement theories is presented. Then evaluations using these theories for various power cable configurations are made, and it is shown that theories considering a hyperboloidal protrusion will exhibit more realistic stress enhancement results than the cases based on a spheroidal protrusion. Further examination reveals that, besides the sharpness of a protrusion, thickness of the insulation medium also plays a governing role in the stress enhancement at the interfaces between different dielectric media. Contrary to the conventional wisdom, it is a surprise to observe that a thicker insulation can actually cause higher stress enhancement at a protrusion tip, under a given applied voltage. Because of this, a flatter surface protrusion at a higher voltage setting, which usually has thicker insulation, can result in earlier degradation than a sharper protrusion at a lower voltage, even though sharper extrusions are expected to have higher stress enhancement. As a result, thicker insulation may not always be advantageous in the power cable design for higher voltage applications.     

Polymeric HVDC Cable Design and Space Charge Accumulation. Part 1: Insulation/Semicon Interface

From theory and experiments, it can be deduced that materials for DC applications should not accumulate a large amount of space charge if accelerated degradation of the insulation system is to be avoided. Therefore, the characterization of DC insulation must take into account the evaluation of space charge accumulation. This cannot be done exhaustively without taking a system approach considering both the semiconductive material and the insulation, in particular, the properties of the semicon/insulation interface. The latter interface, in fact, plays a major role in space charge injection/accumulation in the insulation bulk. Having analyzed different semiconductive and insulating materials candidate for HVDC cable applications, the best solution to be exploited for HVDC cable design would be the combination showing a high threshold for space charge accumulation, a small rate of charge accumulation as a function of electric field and a small activation energy, i.e., a space charge amount less dependent on temperature. Therefore, space charge measurements will provide important information to cable material manufacturers with the aim of tailoring insulation and semicon specifically for HVDC application and, thus, improving the reliability of polymeric cables.     

电缆绝缘屏蔽在终端浸渍剂中的变性

在解剖一个 110 k V交联电缆的故障终端中 ,发现长时间与终端浸渍剂直接接触的交联电缆的绝缘屏蔽发生了严重变性。验证试验表明交联电缆的绝缘屏蔽材料与常用终端浸渍剂的相溶性能很差 ,长时间接触会导致绝缘屏蔽材料的物理机械性能和电导率发生很大变化。在设计、制造和安装交联电缆终端时 ,应该注意电缆的绝缘屏蔽与终端浸渍剂的隔绝。     

Polymer insulated high voltage cables

This article reviews the different components, conductors, semiconductive shields, insulation, sheaths, and jackets, that make up extruded, high-voltage cables. The different types of conductors are described as are the different insulation systems that are available for medium and HV cables. There is a comparison of the two main insulators used in extruded HV cables, EPR, and XLPE. Each material has some properties that are better than those of the other material.     

Development of 500-kV XLPE cables and accessories for long distanceunderground transmission line-Part I: insulation design of cables

This paper discusses the results of a basic study for the development of 500 kV XLPE power cables. The authors have established that the factors that decide the performance of today's XLPE cables are impurities in the insulator and protrusions on the semiconductive layer, and that the insulation performance of XLPE power cables is determined by the size of these defects. In model tests of XLPE power cables, the minimum insulation breakdown stress of cables was determined, to set the design values for 500 kV XLPE cable. As a result, it was found that it is possible to design cables having an insulation thickness of 25 mm