酸碱环境及表面划痕对电缆防蚁护层有效性影响试验

广州属蚁害多发地区,因此埋地电缆多采用退敌虫层或者退灭虫层与外护层材料双层共挤而成的物理型防蚁电缆。为了研究酸碱环境及表面划痕对电缆防蚁护层性能的影响,对退敌虫层及退灭虫层试品分别进行3个月、6个月酸碱老化处理及划痕处理后进行实验群体法白蚁试验。实验结果表明:全新电缆试品蛀蚀等级为2级;酸碱老化作用在短期内能改善防蚁护层的防蚁性能,碱性环境改善效果优于酸性环境;退敌虫层蛀蚀深度明显大于退灭虫层,但按照现有评定标准两者的蛀蚀等级均为2级,建议细化以蛀蚀深度为核心指标的白蚁蛀蚀评定等级,并量化蛀蚀面积指标。     

无毒无害的防白蚁电缆

论述了白蚁对电缆的危害、电缆防白蚁研究现状和技术动向 ,对化学防蚁法和物理防蚁法作了技术比较 ,根据电缆线路易受白蚁侵害的情况和人类对环保的要求 ,提出了应该大力发展无毒无害的物理法防白蚁电缆的观点。     

高压电缆防治白蚁蛀蚀措施初探

近年来由于白蚁蛀蚀电缆引起故障和造成缺陷事例有不断上升的趋势,为此广州分公司组织开展了高压电缆防止白蚁蛀蚀的研究。通过与专业科研机构合作并结合广州地区高压电缆的安装情况,对多个专题进行了研究,经过调研和实验室试验初步得出一些结论,可为生产和进一步研究高压电缆防白蚁提供参考。     

埋地塑料电缆的防蚁简介

有“无牙老虎”之称的白蚁,对埋地塑料电缆的危害极大。作者在列举了我国目前采用的5种电缆防蚁方法后指出,采用防蚁电缆是最明智的选择。     

如何防治电缆遭受蚁害

通过实例说明电缆遭受蚁害造成的后果十分严重，分析了蚁害发生的原因，说明了南方特殊的地理、气候条件决定了该地区为白蚁重灾区，并从物理、化学方面提出了电缆防蚁的方法。     

电缆防白蚁问题的探讨

通过实例说明电缆遭受蚁害造成的后果十分严重 ,分析了蚁害发生的原因 ,说明了南方特殊的地理、气候条件决定了该地区为白蚁重灾区 ,并从物理、化学方面提出了电缆防蚁的方法 ,并用取得的实际效果进行了验证。     

防白蚁电缆的生产及使用效果报告

一、前言 为了推广应用已获得的科研成果,在1971年及1972年小批试验性的试制及实地使用的基础上,于1973年又进行了扩大试制及应用。到目前为止,省内总共敷设了防蚁电缆已近七十公里,在澄海、电白、文昌、大浦、徐闻及湛江等县(市)邮电局供实际使用,以观察其长期防蚁效果。本报告主要介绍广东省电缆蚁害及防蚁电缆生产和使用效果。 二、试验地区的白蚁及其危害 情况: 在我国,白蚁分布甚广,到目前为止,全国已有20个省、市、自治区都发现了白蚁,其中以云南省的白蚁种类为最多,达50余种;广东省次之,达42种之多。在广东,对国民经济有危害的白蚁达十余种,而对电线电缆护层材料——塑料具有危害的主要为家白     

氯丹及其在防白蚁电缆中的应用

<正> 电缆为白蚁所害,是个世界性的严重问题,尤其是塑料、橡皮电缆的受害更为严重。在我国南方,有故障率高达80％的记录。在日本、东南亚、澳大利亚、中东、非洲、拉丁美洲、美国等地,电缆为白蚁所害也常有所见。因此,如何使电缆具有抗蚁性,便成为国内外有关研究者的重要课题。目前,有关电缆防白蚁的方法,从制造的角度出发,大体有下列三种:(1)增大电缆护套的硬度;(2)在电缆护套中混入防蚁剂;(3)采用金属带铠装。其中第1种所用     

非药剂型埋地塑料电缆抗白蚁蛀蚀的室内试验

<正> 在中国南方,常用的软聚氯乙烯、聚乙烯和橡皮电缆,极易受白蚁侵袭。其中埋地塑料通信电缆和电力电缆因白蚁蛀蚀引起的故障非常严重,约占故障总数的60～70％。为此,曾经用一些性能稳定而残效期长的有机农药,如狄氏剂、艾氏剂、七氯、氯丹及林丹等,掺入塑料护套制作成防蚁电缆,但这些药剂毒性太大,严重污染环境,所以许多国家已相继禁止使用。经过多年试验,确认了尼龙-12是一种良好的抗蚁蛀材料,但它价格昂贵,还不能大量应用。1981年9月,澳大利     

防蚁护层塑料对云南省土栖白蚁毒力测定初步试验报告

一、前言 云南省西双版纳自治州,为我国白蚁分布最多的地区之一,到目前为止,云南省发现白蚁达50余种。白蚁对建筑物及作物的危害亦相当严重而普遍。由于该地区有较高大的白蚁塚,土栖白蚁极为丰富,并具有热带非洲的景观。故这次进行防蚁护层塑料对土栖白蚁毒力测定,对全塑电线电缆在土栖白蚁活动猖狂的地区使用,对援外出口到非洲地区的防蚁电缆的试制,具有一定的参考价值以及实用意义。 由于我国国内过去较多的毒力测定主要用家白蚁,几乎没有进行过土栖白蚁的毒力测定工作,而国外情况则相反,比较少的采用家白蚁(在1960年以前),研究工作大多采用象白蚁属、土白蚁属、木白蚁属、异白蚁属以及散白蚁属的一些种类作为试验用     

城市电缆白蚁防治方法探讨

通过介绍白蚁对电缆的危害,分析了城市电缆受白蚁侵害的原因。针对已运行和新拟建的电缆,提出一些有效的白蚁防治防范措施,如生态防治法、生物防治法、物理防治法和化学防治法等。     

高压电力电缆白蚁危害及综合治理研究

;随着我国国民经济的飞跃发展,电力及输电线路也获得了飞速发展。高压电力电缆的埋地敷设安全可靠,不占有空间,美化城市的容貌,占地也少,因此,埋地的电力电缆输电线路也获得飞速发展。但是近年来,尤其是我国南方地区受白蚁侵蚀问题日益严重,严重影响电网运行的安全稳定。本文针对广东东莞供电局110 kV高压电缆的白蚁危害情况,分析白蚁选择电缆嚼食的原因,并对电缆综合治理白蚁危害进行了探讨。     

国内火电厂电气监控系统的应用和发展方向

分析了国内火电厂电气监控系统(ECS)的产生、发展和电气系统接入集散控制系统(DCS)的不同模式在应用中存在的问题,认为“硬接线 通信”方式是目前火电厂电气系统接入DCS的主流解决方案。针对应用中存在的问题,通过技术的改进、参与各方的密切配合一定会很好的解决,随着通信技术的日趋成熟和稳定,完全取消硬接线的全通信方式也一定会逐步推广。     

Ampacity of cables in single covered trays

A mathematical thermal model is developed to predict the operating temperatures of cables in a single covered tray when there is load diversity in the power cable bundle. The model accommodates two different loading scenarios: one in which the heat is distributed evenly across the cable tray cross section; and one which concentrates the heavily loaded cables along the centerline, while surrounding them with more lightly loaded cables. The temperature predictions provided by the model are compared to data found in other IEEE papers, data collected in laboratory measurements, and new data from a four-year study of cable trays in an operating nuclear plant. Reasons for differences between the field data and the computer results are discussed. The model is used to evaluate the conservatism in the available Codes and Standards. A derating factor is introduced that is defined in terms of the ampacity of power cables in open-top trays. The derating factor accounts for the added thermal resistance present when a cover is placed over the cables, trapping a layer of stagnant air on top of the cable mass. The computer model is then used to predict values for the derating factor as a function of cable depth. The derating factor is shown to be independent of the composition of cables in the tray. The presence of a cover is shown to reduce the ampacity based on an uncovered tray by up to 25 percent depending on the depth of the cables in the tray     

New Airport Distribution System with Closed-Loop Circuit?Remote Operation and Monitoring

Unique distribution design to accommodate load growth for an airport facility features an economic approach to sectionalizing and supervisory control. A distribution vacuum interrupter switch with automatic controls provides low-cost light-duty breaker functions to upgrade the existing facility. Unusual equipment mounting positions, particularly high-voltage switchgear hung from hallway ceilings, save valuable space and construction costs. A new ring main bus arrangement with central dispatch and control is described. The design is geared to provide maximum continuity for a system whose XLP cables are exposed to a salt water environment.     

多端柔性直流输电能效计量系统设计与实现

为监测柔性直流输电系统各能耗设备及整体系统的损耗,开发了一套多端柔性直流输电能效计量系统,该系统通过采集调度主站电能量采集系统及数据采集与监视控制(SCADA)系统中的数据,并通过能耗计算模型实时计算,实现柔性直流输电系统在不同运行状态下的系统整体、换流站、能耗设备及电缆的实时能效监视、能效统计以及经济化运行分析等功能.该系统对能效计量系统的建设可起到借鉴作用.     

Effects of crosslinking byproducts on space charge formation in crosslinked polyethylene

Space charge is formed in cables insulated with crosslinked polyethylene. It has not been clear whether the crosslinking byproducts or the crosslinked polymer morphology is responsible for the space charge formation. In order to clarify this point additive-free noncrosslinked low-density polyethylene, additive-free crosslinked polyethylene, and degassed crosslinked polyethylene were soaked in the crosslinking byproducts and the space charge distribution was measured after DC voltage application. Samples tested are divided into two categories. The first category is a soaked single-layered sheet and the second category is a two-layered specimen consisting of a soaked sheet and a nonsoaked sheet. As a result, the following conclusions were obtained. (1) Cumyl alcohol is responsible for homocharge layers in front of the electrodes in both low-density and crosslinked polyethylene sheets. (2) Acetophenone is responsible for heterocharge formation in crosslinked polyethylene, presumably as a synergistic effect with water. (3) alpha -methylstyrene has no effect on space charge formation in low-density polyethylene, while it assists charge trapping in crosslinked polyethylene. (4) Charge trapping occurs easier in degassed crosslinked polyethylene than in low-density polyethylene, probably because of carbonyl groups induced by crosslinking     

The application of real-time monitoring and rating to HPOF pipecable systems

The Boston Edison Company has installed real-time monitoring and rating equipment on two independent pairs of 115 kV HPOF (high-pressure oil-filled) pipe-type cables. The real-time systems are remotely located at cable terminal locations so that critical data inputs can be hard-wired to the computing processor. Real-time information is made available via analog SCADA (supervisory control and data acquisition) connections and also by IBM PCs equipped with modems, which can call the remote systems to view real-time conditions or unload historical data. A PC software package complements the real-time system and gives planners, system operators, and cable engineers the ability to simulate cable system operation in an offline environment. In general, the identification of effective earth parameters in real-time is shown to result in increased emergency and normal ratings by replacing the conservative assumptions that must be made at the design stage with accurate real-time data. Lightly loaded circuits have exhibited large increases in short-time emergency ratings, as they normally operate at relatively low temperatures