阻水型220kV交联电缆的研制

介绍了 2 2 0 k V阻水型交联电缆的屏蔽、绝缘厚度设计、阻水设计和试制过程的工艺要点。试品的型式试验技术指标完全达到设计要求     

低温绝缘（CD）高温超导电缆屏蔽层电流对超导电缆导体和屏蔽电流分布的影响

文中首次提出低温绝缘（CD）高温超导电缆在屏蔽层通过与导体电流相等的反向电流条件下,屏蔽层自感、屏蔽层层间互感、屏蔽层与导体间互感的计算式,以及CD绝缘高温超导电统屏蔽和导体电流均匀分布的设计计算方法。通过对几种典型的屏蔽和导体结构的CD绝缘高温超导电缆屏蔽电流和导体电流分布计算,分析研究屏蔽层电流对CD绝缘高温超导电缆的导体和屏蔽电流分布的影响,并推荐将文中提出的计算方法作为CD绝缘高温超导电缆导体和屏蔽结构的设计基础。完善的计算机程序已缟制完成,可作为实际应用。     

固体绝缘环网柜局部放电分析与结构优化

随着高压开关柜性能稳定、绿色环保、高低温环境适应性强的设计要求被提出,固体绝缘开关成为当下的设计新方向。固体绝缘开关是采用环氧树脂作为主绝缘材料,将真空灭弧室、铜导体等一体浇筑成型的电气设备。分析某公司的12 kV固体绝缘环网柜发生的局部放电位置和原因,提出相应局部放电解决方案。使用有限元分析软件ANSYS Maxwell进行三维模型电场计算,研究发现金属屏蔽罩能够有效改善固体开关模块内部场强,仿真结果满足绝缘要求。最后产品通过试制与型式试验,使产品满足工业化的生产需求。     

导体扇形尺寸的计算方法

<正> 在设计多芯电力电缆结构时,为了缩小电缆外径,节约原材料,往往将导电线芯的横截面设计成扇形。这种“导体扇形”的尺寸计算,可按图1进行。在设计时,一般已知条件是:(1)“导体扇形”截面积S_计=So/ηoSo为导体实际截面积,η为填充系数;(2)中心角2β;(3)相绝缘厚度Δ;(4)中央圆弧化半径r1;(5)边侧圆弧化半     

550kV SF_6气体绝缘GIS套管内屏蔽结构研究

主要介绍了550 kV SF6气体绝缘GIS套管的内绝缘屏蔽结构形式。针对550 kV SF6气体绝缘GIS套管传统的双屏蔽层结构形式所带来的装配难、局放高和成本高等缺陷,通过建立电场模型及优化设计平台,选取了经电场优化的单屏蔽层方案,有效避免了传统的双屏蔽层设计所带来的问题。经型式试验验证,产品各项性能指标满足技术规范要求,绝缘试验合格并具有较大的裕度,套管具有良好的技术经济指标。     

550kV SF6汽体绝缘GIS套管内屏蔽结构研究

主要介绍了550 kV SF6气体绝缘GIS套管的内绝缘屏蔽结构形式.针对550 kV SF6气体绝缘GIS套管传统的双屏蔽层结构形式所带来的装配难、局放高和成本高等缺陷,通过建立电场模型及优化设计平台,选取了经电场优化的单屏蔽层方案,有效避免了传统的双屏蔽层设计所带来的问题.经型式试验验证,产品各项性能指标满足技术规...     

X射线电缆绝缘线芯测偏仪的研制

介绍了一种使用 X射线进行电缆绝缘线芯偏心测量的装置 ,可以测量高压交联电力电缆绝缘线芯各层(导体半导电屏蔽层、绝缘层、绝缘半导电屏蔽层 )的厚度及偏心。     

环氧树脂浇注类绝缘管型母线的结构参数核算

为保证绝缘管型母线的产品质量和运行可靠性,必须针对不同类型的绝缘管型母线的结构参数进行核算。该文分析了绝缘管型母线的结构设计原则和影响因素,并以10k V/4 000A环氧树脂浇注型为例,基于有限元法分析了母线直线段、弯管部分、中间连接的电场强度与温度场分布。同时研究了导体外径、导体直径、屏蔽层数量、绝缘层厚度等关键设计量对其结构设计的影响,为其结构优化奠定基础。     

运行老化XLPE电缆导体屏蔽层侧绝缘缺陷分析

运行老化交联聚乙烯(cross-linked polyethylene, XLPE)电缆导体屏蔽层侧的绝缘缺陷尚未引起充分关注。该文对新电缆及退运的老化电缆进行了超低频介损和微观理化性能对比测试,发现退运电缆处于严重老化状态,且导体屏蔽层侧的绝缘内部存在连续的片状老化缺陷。对退运电缆进行扫描电镜测试发现,导体屏蔽层与内侧绝缘层存在大量微孔。能谱分析证明,电缆老化后的导体屏蔽层及内侧绝缘中均有少量铝(Al)元素的存在。进一步采用红外光谱测试发现导体屏蔽层中的乙烯共聚物(ethylene-vinyl acetate copolymer,EVA)产生了老化降解,且内侧绝缘存在较为明显的羰基与羟基的红外吸收峰。因此,电缆运行过程中导体屏蔽层中的EVA可能存在一定程度的老化降解,降解产物进入绝缘内部参与XLPE的氧化降解反应,进而导致了导体屏蔽层侧的绝缘内部出现连续片状老化缺陷。     

全塑电力电缆用实芯扇形铝导体的生产

<正> 固定敷设铝芯全塑低压电力电缆的导电线芯,在国外已趋向实芯化。本厂从1973年用热挤法生产的实芯扇形铝导体试制1千伏聚氯乙烯绝缘及护套电力电缆起,到目前已将实芯铝导体全塑力缆发展成为一个新的产品系列,最大导体截面为240毫米~2。从产品出厂试验和型     

特高压线路的避雷线保护范围设计

目前,在特高压线路的避雷线保护范围设计中,仍采用传统的不考虑特高压导线电压影响的方法,可能使特高压线路避雷线的实际保护范围满足不了高可靠性防雷设计的要求。为了解决这一问题,在特高压线路的避雷线保护范围设计中,考虑特高压导线电压的影响,提出以特高压导线的最小对地空气间隙距离为半径,构成特高压导线的等效绝缘截面,并设计该等效绝缘截面位于避雷线的保护范围之内。计算结果表明,若不考虑特高压导线电压的影响,特高压线路的避雷线保护范围将存在严重的安全隐患。     

500 Ω-m-low enough resistivity for a cable ground shieldsemicon?

In modern distribution cables, the stress control layers extruded over the conductor and insulation play a critical role in protecting the insulation from stress caused by the conductor, shield wires, tapes, etc. This paper considers the requirements for the conductor and ground shield stress control layers. Finite element analysis suggests that a resistivity of 500 Ω-m is too high a resistivity for a ground shield semicon, as it could result in lightning-induced flashovers between the neutral wires and semicon     

Underground cable technical trends for the largest rural electricco-ops

This paper discusses the technical trends, purchasing requirements, and installation practices for medium-voltage (15-35 kV) underground residential distribution (URD) insulated power cables specified by rural electric co-ops. The data was obtained from survey replies by 50 of the largest electric cooperatives, selected on their number of underground miles installed. These utilities furnished key information about their specification preferences for URD power cables including the following: filled/solid conductors, insulation and conductor shield compounds, extrusion and curing methods, copper neutral type, jacket type and material, and cable acceptance tests. Utilities also provided information on the number of cable miles purchased each year, the voltage class and insulation thickness specified and the percentage of cable direct buried versus installed in duct. The results provide meaningful information that enables all rural electric co-ops to determine whether or not their own URD cable specifications are keeping pace with the industry     

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     

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 comprehensive circuit model for partial discharge activities in cable insulation due to electrical treeing

A new comprehensive circuit model is proposed for electrical trees in cable insulation to be used in partial discharge (PD) analyses. Simple relations are presented for each of circuit components. The effect of tree’s constructional parameters (such as length, growth angle and type), cable and insulation dimension (such as conductor radius and insulation thickness), needle dimension, temperature and insulation aging are considered in the proposed model. The patterns (pulse sequences, φ–q–n and φ–n) extracted from the proposed model are in a good agreement with the published experimental patterns under different conditions. Moreover, the model is fully compatible with the software packages, such as EMTP, that can simulate pulse propagation along cable networks.     

Design of the winding–bushing interconnections in large power transformers

The paper presents the improvement in design of the conductor connecting the windings and bushings in oil power transformers. This is a sensitive part of large transformers and there is a need to optimise its manufacturing time and costs. The thermal problem of the heating of this conductor with increased insulation thickness on a part of it is treated using a non-linear two-dimensional thermal model. The experiments performed made determining of some problematic parameters (heat resistance of oil-paper insulation and the paper to oil convection heat transfer coefficient) of the thermal model feasible. The results obtained are of practical interest in the design practice of interconnections, but also affect the important parameters of heat transfer by devices with oil immersed paper insulation.     

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。     

硫化工艺对抗水树交联聚乙烯绝缘电力电缆工频击穿性能的影响

为了研究不同硫化工艺对抗水树枝交联聚乙烯绝缘电缆击穿性能的影响,建立了相应的试验手段和评价程序。将使用相同导体屏蔽料、抗水树绝缘料、绝缘屏蔽料,并采用5种不同硫化工艺(A、B、C、D、E)生产的电压等级、型号规格相同且结构相似的电缆作为研究对象,每种电缆取6段作样品,共30段。分别对老化前和老化180d后的5种样品进行工频击穿试验,并观察击穿后样品切片的水树枝、界面微孔、突起和绝缘中的微孔、杂质。试验结果表明:经过180d的加速老化后,5种样品中均无微孔、界面光滑、有少量尺寸较小的杂质,不会导致击穿性能下降;不同硫化工艺生产的电缆工频击穿性能表现出明显差异,其中,A硫化工艺生产的电缆工频击穿强度下降了53.53%,击穿后的样品中观察到了水树枝,B、C硫化工艺生产的电缆工频击穿强度也有不同程度的下降,而D、E硫化工艺生产的电缆的工频击穿强度没有降低,说明硫化工艺对工频击穿强度有直接的影响,并建议实际生产中确定硫化工艺时,各区温度设定应逐渐降低,且初始硫化温度不应过低,生产线速度应适当。