Study on development of dry band on ADSS fibre optic cable

All dielectric self supporting (ADSS) fiber optic cables are suffering from damage caused by dry-band arcing. This paper investigates the formation of the dry band, which is crucial to the arcing. The formation of the dry band is the result of evaporation of water deposit some point on the cable surface. When the dry band is formed the current is interrupted. Then high voltage is applied to the small gap separated by the dry band, and may cause arcing. This paper discusses the drying process of the wet layer on the surface of the cable in detail. The differential equation of the drying rate is formulated and numerical simulation is performed. With this equation, the time-to-arcing and variation of the layer resistance can be estimated. For verification of the results, the time-to-arcing and layer resistance are measured in the laboratory. The numerical results provide guidance for design of an automatic dry-band arcing aging test system. The onset of arcing is investigated based on the results.     

Damages and destruction of fiber optic cables on 161 kV overheadtransmission lines

All-dielectric self-supporting (ADSS) fiber optic cables are in use now on high-voltage (HV) and extra-high-voltage (EHV) overhead transmission lines (OHTL) in many countries all over the world. Their use allows the creation of highly effective data communication channels along the OHTL. However, in subtropical areas with specific climatic conditions, dry-band partial arcs have been found on the polyethylene external protective enclosure cable surface. This paper describes the various investigations performed to understand the causes for damage to ADSS fiber optic cable installed on four 161 kV OHTL and on one 110 kV, in the subtropical climate of Israel     

Algorithm to predict dry-band arcing in fiber-optic cables

Utilities frequently use ADSS (all dielectric self-supporting) fiber-optic cables installed on transmission lines 3-6 m below the high voltage conductors. Dry-band arcing occurs on the fiber-optic cables when the cables are polluted and wet. This has been assumed to cause cable failures. An equivalent circuit has been developed to represent the polluted fiber-optic cable in the high voltage environment. The objective of this paper is to present a novel numerical method that can be used to predict dry-band arcing in fiber-optic cables. KCL (Kirchoff's current law) is used to derive node point equations for the equivalent circuit. Forward elimination and backward substitution of node voltage is used to solve the equations. The effect of pollution, tower arrangement, and conductor sag is analyzed. The numerical method has speed advantages over circuit simulation methods. This method includes conductor sag, nonuniform pollution, and variable capacitance. This algorithm can be used to predict dry band arcing in fiber-optic cables     

Engineering a solution to the aging of HV self-supporting cables by dry-band arcing

The retrofit rod of controlled resistivity clearly has the potential to remove the threat of dry-band arc damage on all-dielectric, self-supporting (ADSS) cables. This is achieved by reducing the maximum current available on the cable for arcing activity. Rods can be applied to polyethylene sheathed cables or arc-resistant sheathed cables and can improve the performance of both. Extensive trials in the UK have shown that the rod works and have confirmed predictions of computer models. However, the engineering of the application of such as solution is complex. Individual spans of different geometry, including cable sag, must be considered. In particular, local variation in pollution is critical; so knowledge of the proximity of the sea or industry must be considered. It is also very likely areas that do not experience much rainfall will be particularly onerous because the cable will not be naturally washed regularly, so the pollution on its surface will tend to build up, reducing its resistance in times of high humidity, fog, and dew.     

ADSS光缆在电力通信网中的应用

全介质自承式(ADSS)光缆的设计施工是一项综合性的系统工程。给出了ADSS光缆挂点的空间电位的控制值,在最大弧垂下光缆必须保持与各种交越物的安全距离,ADSS光缆配盘原则及配盘长度经验公式,介绍了耐张线夹、垂悬线夹、防振装置的配置情况,总结了ADSS光缆施工要点。     

ADSS光缆外护套抗干带飞弧能力的新试验方法

首先简要地回顾了ADSS光缆外护套受干带飞弧侵蚀的机理，介绍了国外近年来研究试用的外护套抗干带飞弧试验的新方法和应用这种新方法所取得的实验结果。根据这些结果和其他考虑，提出了尚待进一步探讨的若干问题。     

Electrical design parameters of all-dielectric-self-supportingfiber optic cable

A lumped circuit model for calculating voltages and currents on all-dielectric self-supporting (ADSS) fiber optic cable near high voltage transmission lines has been developed. The model has been used to show that contamination levels, tower attachment points, relative ADSS and conductor sag and electrical phasing of the conductors are important parameters and must be considered in calculations, especially when determining the possibility of dry band arcs which could lead to cable damage     

ADSS光缆的施工,测试和竣工验收

介绍了ＡＤＤ光缆通信工程中光缆施工方法、注意事项、光缆熔接测试时的技术要求,以及光缆竣工验收的主要内容等。     

新乡220 kV输电线路ADSS断缆事故分析

文章简要介绍了电力电磁场与力场的耦合计算，以及仿真系统（NASTEL）采用的输电线路周围电位和电场计算的基本方法，应用该软件计算了新乡220kV输电线路ADSS光缆周围的电位和电场分布，重点分析了转角和跳线对电场分布的影响，揭示了断缆事故发生的原因，最后针对电力系统ADSS光缆的设计和施工提出了一些建议。     

运行中的ADSS光缆故障分析及措施

对运行中的全介质自承式（ADSS）光缆故障原因进行了简要分析。造成此类故障的主要原因是挂点处的高场强在金具出口处产生较大的表面漏电流，形成干燥带，在此处反复放电，造成光缆表面电腐蚀，最终导致光缆断芯断缆故障。综合各种因素及通过市场调查，在容易发生电腐蚀的金具附近采用一种高科技涂料来防止光缆表面老化，阻止光缆表面与金具接合处产生电弧，减少ADSS光缆电腐蚀故障，取得了成效。     

应用三维频域电场计算方法确定高压输电线路铁塔ADSS光缆的悬挂位置

介绍了将三维频域电场计算方法应用于高压输电线路铁塔附近三维工频电场计算，通过对500kV输电线路6种不同铁塔结构附近的三维工频电场分布的测量，确认了所用方法的有效性。应用上述方法对河北南网220kV输电线路10种和110kV输电线路18种不同铁塔结构附近的三维工频电场进行了详细计算和分析，获得了各种铁塔附近三维工频电场的空间分布，找出了适于ADSS光缆悬挂的低场强空间。该研究成果已用于指导河北南网多条高压输电线路铁塔ADSS光缆悬挂位置的选择。     

我国全介质自承式光缆的运行状况及抗电腐蚀措施

近年来全介质自承式(All-DielectricSelf-Supporting,ADSS)光缆在运行中受电腐蚀损坏频繁发生,文章调查了我国25个省(自治区)和5大城市的ADSS光缆运行状况。调查发现:ADSS光缆的运行状况与气象和污秽环境有关,如东北三省220kV线路上ADSS光缆运行良好,而渤海湾沿海是严重污秽区,光缆电腐蚀严重;110kV及以下电压等级线路的ADSS光缆普遍运行良好;电腐蚀原因是防震鞭材质不耐电腐蚀和防震鞭与光缆金具之间距离近;光缆挂点选择不当和光缆质量问题。建议采取如下抗电腐蚀措施:防震锤代替防震鞭;220kV线路上采用防晕环(圈);修补已被腐蚀的光缆护套;杆塔与金具间串入硅橡胶绝缘子等。同时建议110kV线路不宜普遍用光纤复合架空地线,宜用ADSS光缆。     

ADSS光缆的张力、应变设计与计算

介绍了全介质自承式（ADSS）架空光缆的结构设计计算，并对其中架空悬链线的数学模型及有关计算作了详细论述。     

光纤电流差动保护在高压线路保护中的应用

在220kV及以上的超高压输变电工程中,随着OPGW、ADSS等光缆在输电线路中的使用,光纤电流差动保护因其保护原理简单、动作快速、不受串补影响、能可靠地反应线路上各种类型故障等优点,作为超高压线路主保护之一得到了越来越广泛的应用。     

工程建设期间影响ADSS光缆运行可靠性的几个因素

叙述了ＡＤＳＳ光缆的安全可靠运行与设计、产品质量、施工质量、维护管理等各个环节的关系。强调协调了ＡＤＳＳ光缆工程建设中各环节的关系和做好ＡＤＳＳ光缆建设期间的各项工作,将为今后ＡＤＳＳ光缆的可靠运行打好基础。     

电弧反射电缆故障测距装置脉冲发射时刻选择算法

电弧反射法(ARM)是一种广泛应用的电缆故障测距方法.由于不清楚测试过程中电缆故障点电弧电阻的动态特性,因此施加测试脉冲时脉冲发射时刻的选择比较困难.分析了ARM测距装置放电过程中的电压和电流特性,以及故障点的电弧电阻特性.论证了在直流电弧放电阶段电弧电阻较低而且稳定,是发射脉冲的最佳时段.据此提出根据电流最大值和故障...     

OPPC光缆:一种新兴电力通信解决方案

光纤复合架空相线(OPPC)是将光纤单元复合在架空相线中的光缆,具有电力架空相线和光通信双重功能。在传统三相输电线路中,采用OPPC光缆替代三相中的一相,形成由2根导线和1根OPPC光缆组合而成的三相电力系统。OPPC光缆技术是OPGW、ADSS技术的应用延伸和有益补充,可以填补不能适用OPGW、ADSS的应用空白,如10、35、66kV及以下线路等中低压城农网通信改造,某些110kV线路,OPPC光缆应用于风电输电线路也有一定技术经济优势。作为一种新兴电力通信解决方案,OPPC光缆利用其比较优势具有一定的应用前景。     

OPGW 在750 kV官亭变-兰州东变输电线路上的应用

文章介绍了OPGW在国内首个750 kV超高压(西北官亭变—兰州东变)输电线路上的应用。结合西北750 kV输电线路的特点和对OPGW的要求,描述了750 kV输电线路OPGW光缆结构设计的特点,同时通过对其在生产制造(原材料选择、工艺控制等)、施工等方面质量控制的介绍,分析了OPGW光缆指标测试的结果,探讨了750 kV输电线路大档距OPGW光缆防振试验,并为西北750 kV输电线路1 235 m大档距OPGW光缆推荐了满足技术条件的直线档防振方案,对探索和积累750 kV超高压等级上OPGW光缆的设计、生产和施工经验具有现实意义。     

直流接触器触头电弧侵蚀特性

触头开断过程中会产生电弧,从而导致触头表面被侵蚀,影响其电接触性能。由于直流供电系统不存在自然过零点,致使直流接触器触头受电弧侵蚀影响比交流接触器更加严重。为了研究电弧对触头的侵蚀作用,基于磁流体动力学理论,考虑电弧与触头之间的能量耦合,建立电弧-触头动态耦合模型,研究了电流等级和分断速度对触头电弧侵蚀特性的影响。仿真结果表明：近阳极区电弧温度高于近阴极区电弧温度;电流等级由20 A提高到30 A时,电弧温度和燃弧时间显著提高,燃弧能量增加75.93%,使得触头侵蚀更加严重;触头分断速度由0.1 m/s增加到0.2 m/s时,电压电流的变化率提高,燃弧时间和熔池体积减小,燃弧能量减少47.83%,电弧对触头的侵蚀作用降低。实验结果与仿真相吻合,验证了仿真模型的正确性。     

故障电弧模拟测试系统及不确定因素的研究

针对低压系统故障电弧问题设计了一套故障电弧模拟测试系统,该系统含有上位机模块、下位机控制模块等,可以实现切割电缆、碳化路径及点接触3种类型故障电弧输出。同时,采用Logistic识别算法作为故障电弧保护电器检测的辅助判据。通过对系统中存在的不确定因素进行分析,选取切割电缆模块中的切割速度、电缆线径与电流幅值,以及点接触模块中的拉弧速度与接触面积作为主要影响因素进行研究。研究表明,在特定条件下电流零休时间会呈现趋势性变化,改变单一条件可使其变化1 ms左右。依据研究结果选取最合适的起弧条件,以提高故障电弧保护电器检测结果的准确性。