屏蔽材料对XLPE电力电缆工频击穿特性的影响

为检验不同屏蔽材料对抗水树电缆抗水树枝能力的影响,建立了抗水树屏蔽材料性能试验手段和评价程序,在同一制造厂家分别采用两种不同电缆屏蔽材料,生产同一屏蔽结构的交联聚乙烯(XLPE)电力电缆,并制作成30段电缆试样。在相同试验条件下,进行14d负荷循环、120d加速老化、180d加速老化和360d加速老化,然后对老化前原始试样和老化后电缆试样共5种不同老化状态的电缆试样进行工频逐级击穿,试验研究不同屏蔽材料组成的XLPE电力电缆的工频击穿特性。试验结果表明,国产普通屏蔽材料制造的XLPE电力电缆的工频击穿特性相对进口抗水树电缆屏蔽材料制造的XLPE电力电缆的工频击穿特性存在明显差异,进口抗水树电缆屏蔽材料制造的XLPE电力电缆经过360d加速老化试验后仍保持较好的工频击穿特性,安全运行寿命较长。     

抗水树XLPE电力电缆的工频击穿特性

为检验电缆材料是否具有抗水树枝能力,建立抗水树枝材料性能试验手段和评价程序,在同一制造厂分别采用5种不同电缆绝缘料,生产同一绝缘结构的电缆,并制作成90个电缆试样。在相同试验条件下,进行14d负荷循环、120d加速老化、180d加速老化、360d加速老化和480d加速老化试验,然后对老化前原始样和老化后电缆试样共6种不同老化状态的电缆试样进行工频逐级击穿,试验研究XLPE电力电缆工频击穿特性。试验结果表明:普通电缆绝缘料制造的XLPE电力电缆工频击穿特性相对抗水树电缆绝缘料制造的XLPE电力电缆工频击穿特性存在明显差异,抗水树XLPE电力电缆经过480d加速老化试验后仍保持较好的工频击穿特性,安全运行寿命较长。     

XLPE中压电缆中间接头的界面老化修复研究

电缆中间接头是城市电缆系统中最容易出现问题的部位,为了提高老化后电缆中间接头的绝缘性能,本研究尝试通过向中间接头注入修复液的方法进行修复。首先在潮湿环境下对电缆中间接头进行电热加速老化试验,并向老化后的样本注入修复液进行修复,通过工频介质损耗测量、工频击穿试验和能谱分析对修复前后中间接头样本的结构和性能进行对比分析。结果表明:老化后电缆中间接头的绝缘强度明显下降,而通过修复液修复后其绝缘性能有所提升。通过能谱仪检测发现修复后中间接头界面出现了Si和Ti的氧化物,说明修复液可以扩散进入中间接头界面并与侵入的水汽反应生成有机聚合物,填充在界面气隙空腔位置,从而提高了中间接头的界面击穿电压,达到了修复电缆中间接头的目的。     

交联聚乙烯电缆中水树枝诊断的研究现状

交联聚乙烯（XLPE）电缆因其具有优良的导电性、较好的耐热性和机械强度,自问世以来已广泛应用于输电线路和配电网中。然而,当电缆绝缘处于潮湿的环境中时,在电场的作用下会产生水树枝老化。随着水树枝的生长,电缆的绝缘性能下降并可能导致绝缘击穿,从而影响电网的安全运行。总结了交联聚乙烯电缆中水树枝老化的研究现状,概述了水树枝的产生机理及近年来水树枝老化的诊断方法,最后对各种诊断方法进行了简单比较。     

绝缘形态、杂质和氧化对电缆电气性能的影响

已老化或未老化的实际输配电电缆的交流击穿强度和介质损耗,是随着绝缘结晶度、杂质和氧化情况而变化的。这些参数对于电缆导体屏蔽层附近的影响特别严重,而且系随老化而变化。同时,简要讨论了交联对电缆性能的影响     

上海电缆研究所1981年第二批已鉴定成果简介

<正> 1.充油电缆绝缘工频长期击穿试验研究本研究通过对充油电缆绝缘模拟样品在不同温度梯度、不同绝缘油浸渍绝缘的恒定梯度以及逐级击穿的条件下进行试验,得出如下结论: (1)充油电缆绝缘的长期工频击穿性能符合韦伯尔统计规律,从而有可能运用统计方法进行充油电缆设计及估计充油电缆绝缘运行的可靠性与寿命。     

中压电力电缆用半导电屏蔽料浸水渗透性研究

应用于潮湿场所的中压电力电缆产品,水分会使与绝缘层紧密接触的内外半导电层中的组分迁移或渗透出来,在绝缘层和半导电层界面形成酸性或碱性液滴微粒。这些液滴里的导电离子,在高电场作用下会频繁撞击绝缘表面,形成水树枝,导致电力电缆绝缘层性能迅速劣化击穿,极大降低电缆的使用寿命。通过测试半导电屏蔽料浸水后的pH值、电导率性能,研究了中压电力电缆用半导电屏蔽料浸水渗透性。     

高压交联聚乙烯电缆绝缘径向的力学、电学、理化性能分析

对66 kV退役及加速热氧老化的电缆主绝缘分层导体屏蔽层一侧(内层)、绝缘屏蔽层一侧(外层)取样,利用电子万能拉伸机进行拉伸实验;采用X射线衍射仪、萃取法进行理化实验;采用耐压测试进行工频击穿实验。通过力学、电学、热学耦合仿真分析XLPE绝缘层径向老化性能。结果表明：XLPE材料内外层抗拉伸强度随老化周期的增加呈先增大后减小,断裂伸长率一直减小,XLPE绝缘内外层结晶度、击穿电压呈先增大后减小。     

35 kV及以下XLPE绝缘电力电缆品质分析

按照特殊设计的取样原则,收集了50个运行年限为1~14 a的XLPE绝缘电力电缆样品,通过结构参数和水树枝试验,研究分析XLPE介质中杂质、微孔和不均匀性(偏心度)等结构参数及电缆敷设方式、运行环境条件与XLPE介质水树枝早期劣化现象。研究结果表明,杂质、水分和电场是引发XLPE绝缘电力电缆介质树枝状早期老化的直接因素,并最终导致XLPE绝缘电力电缆发生运行故障。     

交联聚乙烯(XLPE)电缆水树枝老化机理及试验方法

交联聚乙烯 (XLPE)电缆因有种种优点 ,已被广泛应用 ;但这种电缆的绝缘层在潮湿和电场同时作用下会产生水树枝老化 ,甚至可发展到绝缘击穿故障 ,影响正常供用电。为了能及早采取措施 ,防止此类故障 ,了解水树枝的形成机理和导致绝缘击穿的过程 ,在此基础上进行有效的预防性试验势在必行。     

Effect of water on aging of XLPE cable insulation

Cables as elements of power distribution system have great influence on its reliable service and overall planning requirements. During last years, crosslinked polyethylene (XLPE) cables have been more and more used in power systems. This paper presents the results of an investigation of changing of (XLPE) cables insulation breakdown stress (AC BDS) due to water absorption. The paper deals with AC BDS of the following kinds of XLPE cable insulations: steam and dry cured with water tree retardant crosslinked polyethylene (TR-XLPE) and non-tree retardant crosslinked polyethylene (XLPE). During tests, the tap water was injected into, (1) conductor with cable ends closed; (2) into cable conductor with ends opened; and (3) into metallic screen with cable ends opened. The presence of water in XLPE cables was subjected to electrical stress and heating. AC BDS tests were performed as a function of aging time and water content in the cable insulation at different aging temperatures. Also, in this investigation, tests with the changing of AC BDS in the radial direction of unaged and aged XLPE cable insulations were carried out.     

NaCl溶液对XLPE电力电缆工频击穿特性和水树的影响

采用同一根抗水树XLPE电力电缆,分别在自来水和NaCl溶液中进行60 d、120 d和180 d的加速老化试验,然后对老化前和老化后的电缆试样,分别进行工频逐级击穿,对老化后击穿的电缆试样进行水树检查。试验结果表明,NaCl溶液对抗水XLPE电力电缆的老化有明显的作用。     

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.     

Comparative laboratory evaluation of TR-XLPE and XLPE cables with Super-smooth conductor shields

This paper provides data on four commercial tree retardant crosslinked polyethylene (TR-XLPE) and one cross-linked polyethylene (XLPE) insulated 15 kV cables supplied by three manufacturers. The cables have "super-smooth" conductor shields and "extra-clean" insulation and insulation shields. AC and impulse voltage breakdown and selected other characterization data are presented for cables that were aged immersed in room temperature water (15-30/spl deg/C) up to 24 months of a planned 48 months aging program. The five cables have high ac voltage breakdown strength, three of the TR-XLPE cables, actually increased in breakdown strength during aging. The one TR-XLPE cable that had the lowest ac voltage breakdown had vented trees at the insulation shield and high dissipation factor, which the other cables did not have. The impulse voltage breakdown strength of all cables decreased during aging; the cable with the lowest ac voltage breakdown also has the lowest impulse voltage breakdown. The dissimilar performance of the TR-XLPE cables and the excellent performance of the XLPE cable indicates evaluations at longer times are required to differentiate between modern TR-XLPE and XLPE insulated cables.     

用有限元分析交联聚乙烯电缆中水树成长行为的研究

水树是电缆主绝缘的主要劣化现象之一,严重影响电缆的使用寿命。正确评价长有水树的材料的电场分布,对于理解水树的生长机理以及水树引起的介质击穿是非常重要的。采用具有不同物理化学性能的热老化XLPE电缆绝缘和与外加电场梯度方向成一定角度的非常规的水针电极结构进行水树枝加速老化实验,用有限元方法对水树加速老化实验中采用的结构模型进行数值电场分析,研究了水树尖端处电场增强对水树枝老化发展的影响。     

A study of treeing phenomena in the development of insulation for500 kV XLPE cables

This review summarizes research on treeing phenomena, i.e. the formation of electrical trees and water trees, that has been undertaken in Japan for the development of 500 kV XLPE cable. Section 1 presents the results of factors affecting XLPE cable insulation breakdown under commercial ac and lightning impulse voltages. Section 2 verifies the phenomena of electrical tree formation in XLPE cable insulation using block samples and model cables, and gives the results of studies to determine the level electrical field stress initiation for such trees. Section 3 summarizes the results of studies on long-term aging characteristics, which is a particular problem under commercial ac voltages, while Section 4 explains how this research influenced the design of 500 kV XLPE cable insulation. All authors were members of `The investigation committee of fundamental process of treeing degradation' under IEEJ     

热老化对交联聚乙烯电缆绝缘中水树的影响研究

热老化过程不但会影响交联聚乙烯电缆绝缘的电磁学和物理化学性能,还对绝缘内水树的产生与生长有着一定的影响。通过研究热老化过程对XLPE电缆绝缘中的水树现象的影响,以及在几个有可能的影响因素当中,哪个因素对水树现象的影响最大。实验结果表明,在与XLPE电缆绝缘的热老化有关的各种因素对水树现象的影响中,热氧化对XLPE电缆绝缘表层水树的产生和生长的影响最大。尽管热氧化所引起的缺陷有可能就是XLPE电缆绝缘中水树生长过程中的起始点,但是它在一定程度上抑制着水树的成长,甚至有着"水树延迟效果"的美称。     

XLPE电缆绝缘中水树的形成机理和抑制方法分析

叙述了交联聚乙烯电缆中的水树对中高压XLPE电缆的危害性;介绍了水树的本质、水树生长特性,引发水树的电-机械理论和化学反应理论;分析了影响水树生长的因素和国内外抗水树电缆料的研究情况。     

35 kV及以下XLPE电力电缆试验方法的研究

通过对交链聚乙烯（ＸＬＰＥ）电力电缆试品的工频、０．１Ｈｚ超低频和振荡３种击穿电压的平行比对试验研究,探讨能够有效发现、判别ＸＬＰＥ电力电缆运行故障隐患的试验方法,试验研究结果表明：振荡波电压试验能够有效地发现电力电缆及其附件的制造和安装质量缺陷,超低频电压试验能够有效地发现电力电缆及其附件绝缘树枝状早期劣化缺陷;工频电压试验是一种较好的方法,需进一步深入研究。     

Correlation between AC breakdown strength and low frequencydielectric loss of water tree aged XLPE cables

This paper describes experiments performed on laboratory aged 12 kV and service aged 24 kV XLPE cable samples. Results from measurements of residual AC breakdown strength, degree of water treeing and dissipation factors are presented. The dissipation factor at low frequencies was determined by both time and frequency domain measurements. The relationship between these methods are discussed and it is shown that both can be used for assessing the average ageing state of the cable, The results show that water treeing causes reduced residual AC breakdown strength and high and nonlinearly increasing low-frequency dielectric loss