Where do AEIC cable specifications come from?

The objectives of the Association of Edison Illuminating Companies (AEIC), an organization of investor-owned electric utilities and its cable engineering section (CES) are discussed. The goals of the latter are to address the issue of reliable underground cable systems for its member companies, primarily by developing cable specifications and guides for member utilities. The development process is described, the subjects covered are outlined, and sources of input from outside the CES are enumerated     

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     

高压电缆线路与城市地下空间资源协调规划

分析了城市电缆通道规划在总体层面应遵循的基本原则。提出在中心城区以电力隧道,新城城区以综合管沟结合电力排管,新市镇以电力排管为主要电缆通道的地下空间利用方式。论证了电缆通道和城市公共设施的适应性。     

Preventive maintenance testing of shielded power cable systems

Power cable systems can play a critical role with respect to the reliability of industrial plants. This paper reports on a preventive maintenance tool for shielded power cable systems based on the location of partial discharges. It describes the principles of the technology and provides data covering tests conducted on over 6000 km of medium-voltage cables serving both electric utilities and industrial customers. It discusses the technical and economic advantages, as well as some of the limitations of the diagnostic test method     

Performance of reduced wall EPR insulated medium voltage powercables. I. Electrical characteristics

Paper-insulated lead covered power cables (PILC) have had a long and successful heritage. After almost 100 years, this design of cable is still in operation and continues to be manufactured. However, electric utilities are now looking for a reliable replacement for PILC cables. This is due to two primary reasons: (1) the difficulty in installing and maintaining this type of cable; and (2) increasing pressure to replace these cables due to environmental concerns. To date, diameter limitations of conventional extruded dielectric cables has impeded their replacement in existing PILC conduits. This paper describes a study for the evaluation for reliably reducing the insulation thickness to achieve a lower diameter cable to effectively replace PILC cable in existing conduits. Part I of the investigation reviews the theory of insulation wall determination and the test program carried out to evaluate electrical performance of reduced wall EPR cables. Additionally, cable design concepts and constructions are discussed     

Retrofitting-new high voltage XLPE cables substitutingpaper-insulated power cables in steel pipes

Many utilities still have paper-insulated pipe type cables in service. In the near future they may have to replace some of these systems due to local increases in electric power demand or aged cable insulation. In many cases the steel pipes are well protected against corrosion and thus suitable for further use. For retrofitting in such installations, XLPE-insulated cables offer several advantages. Felten & Guilleaume Energietechnik AG has developed a new three-core XLPE-insulated 64/110 kV cable with reduced insulation thickness (10 mm), that can be pulled into a pipe. In co-operation with VEW ENERGIE AG, the cable performance is being investigated in a field test, that started in October 1996. This long-term loading cycle test will last for three years. The test voltage, applied between conductor and earth, amounts to 127 kV. The temperature is measured with the help of an optical-fiber measurement system. This device is computer controlled and works as a remote monitoring system     

Underground cable specification advances and installation practices of the largest investor-owned utilities

This article analyzes the technical specification trends for the design, installation, and use of 15 to 35 kV underground, insulated power cables by 60 of the largest investor-owned utilities. A distinctive 10-year trend has been established in insulation material preferences, and interesting new data are provided on the cable replacement and rejuvenation practices of these utilities. The results provide practical information that will enable all electrical utilities to compare their medium voltage underground cable specifications and installation practices with those of the largest utilities in their industry.     

Technical trends in medium voltage URD cable specifications

It has been more than thirty years since high molecular weight polyethylene (HMWPE) was first introduced as a commercial insulating material for medium voltage (15-35 kV) underground residential distribution (URD) cables. That began a dramatic expansion of utility electrical service that has led to the installation of several million miles of URD cables by over 3,000 utility companies across America. When early cables began failing prematurely, the industry was challenged to diagnose the causes and find corrective solutions that would give utilities the confidence to continue their commitment to underground cable. The past 25 years have been a story of constant technical improvements, increasingly tighter industry specifications and positive advancements in URD cable life performance. This paper discusses the significant technical changes that have taken place during this period and their impact on cable performance. The results of a 1983-1993 ten-year study of the major technical specification changes of the 25 largest Investor-Owned Electric Utility Companies (IOUs) is also presented. The data illustrate how quickly new cable technology is specified by these leading utilities and provide a clear picture of the key technical trends occurring throughout the utility industry during the 1990s     

Mobile radio systems applications in electric/gas utilities. I.PSCC Radio Subcommittee working group report

The Subcommittee conducted a survey of over 32 large Canadian and US electric/gas utilities in January 1988 to determine the status and value of existing mobile radio applications along with plans for future replacement or upgrade. The report is based on the results of the survey and includes a brief history of mobile radio telephone, the types and extent of mobile radio systems in use by electric/gas utilities since 1945 along with plans for replacement and/or upgrade in the next five years, synopsis of a report on a six-month field test of a state-of-the-art digital microprocessor-based mobile radio control system, and a discussion on the value of mobile radio telephone systems to electric/gas utilities. The survey found that utilities are between 20 and 40 years old in terms of the system configuration and signaling/control schemes used and that all of the utilities (100%) plan to replace or upgrade their existing mobile radio systems within the next five years     

Technical advances in the underground medium-voltage cablespecifications of the largest investor-owned utilities in the US

The current and past technical specifications of 45 of the largest investor-owned utilities in the US were studied, and the resulting analysis provides useful information for other electrical utilities to evaluate their medium-voltage underground cable specifications and practices     

10kV XLPE电缆本体缺陷电场仿真分析

为了研究10 k V XLPE电缆本体受伤电场情况,防止电缆缺陷局部放电电场发展导致电缆接头击穿,通过分析XLPE电缆主要缺陷类型及原因来确定引起电缆故障的主要类型故障,然后利用有限元分析方法对电缆本体受伤情况电场进行仿真研究,最后根据仿真结果得出结论:在电缆本体空洞插入铁丝会造成电场畸变,严重时会造成绝缘击穿,为今后电缆线路故障分析提供参考。     

Economics of energy reliability

The types of reliability considerations and the deterministic criteria currently used by most utilities for electric transmission reliability planning are outlined. The complex process of weighing outage costs against prevention costs in this approach is discussed. A probabilistic approach increasingly being adopted by electric utilities is described that allows costs and benefits of reliability to be compared directly     

Utility URD cable experience

The large numbers of failures of primary underground residential distribution (URD) cables that utilities are experiencing is addressed. The major problems are defined and discussed and methods are suggested whereby the utility cable engineer could best find solutions. The problems and decisions fall into two general categories: those that concern existing in-service cables, and those that concern future URD cable designs. The discussion of existing cables covers cable replacement criteria, estimation of life remaining, cost-effective replacement methods, and concentric neutral corrosion. The discussion of future cables covers insulation selection, cable/conduit design, and life expectancy (the first two issues apply to replacement cables as well)     

Forecasting Fossil Fuel Demand

The possibility of interfuel substitution in the generation of electrical energy exists. Given this fact, a demand model for various fossil fuels by electric utilities in the United States is developed. The results obtained using regional data suggest that the responsiveness of the demand for coal, residual fuel oil, distillate fuel oil, and natural gas by electric utilities to relative price changes is significant. In a forecasting setting, the demand model performs remarkably well when actual and forecast values for 1979 are compared.     

基于质量保险的多质量等级电能定价方法

采用基本电价叠加电能质量保险费的价格形成机制,提出一种基于质量保险的多质量等级电能定价方法。引入了最高不合格率和最高违约次数两个重要的概念对基本电能进行约束,规定供电方必须对所有违反用电合同的电能进行赔偿,赔偿单价与保险单价成正比,保险单价由电力用户自由选取。该方法可以有效地分离基本电能价格和电能质量服务价格,促进市场环境下多质量等级电能供应的实现,使得用户可以根据自身情况和服务价格选择合适的电能质量服务,实现电能质量事故的合理赔偿,揭示出电能质量对于配电系统的真实价值,从而指导供电方做出正确的电能质量投资决策。算例表明,这种方法是实用和有效的。     

配网电缆接头内部缺陷电场特征研究及电树发展分析

配网交联聚乙烯(cross linked polyethylene, XLPE)电缆的严重击穿故障大多发生在电缆接头处,主要由电缆接头在制造和安装过程中的工艺缺陷引起。文中采用模拟电荷法研究电缆接头4种典型缺陷,即气隙、水膜、金属碎屑和金属外破附近的电场分布特征;然后采用电场计算与随机漫步理论相结合的方法,分析缺陷引发的电树枝的分布规律。同时,测量带缺陷配网XLPE电缆接头样本周围的实际电场分布,并比较测量结果与计算结果。结果表明,采用电场测量的方法可以直接有效地识别电缆接头内部缺陷类型,相比气隙、水膜缺陷,导电缺陷造成的电场畸变更为显著。缺陷引发的电场畸变大于临界电场值时会引起电树发展,电树发展的轨迹长度与场强大小呈正相关,导电缺陷引发的电树枝有较大概率向缆芯方向发展,更易引起XLPE绝缘击穿。     

Assessment of underground cable ratings based on distributed temperature sensing

Numerous power utilities have installed advanced distributed temperature sensing (DTS) systems to measure the temperature of underground cables. This paper presents a general procedure for real-time assessment of underground cable ratings based on DTS. After the identification and location of hot spots on a cable, the cable installation data, load, and DTS-recorded temperature over a period of time are used to estimate soil thermal parameters and assess cable ratings under normal and overloading conditions. In order to accurately estimate soil thermal parameters, a combined technique of the finite-element method and gradient-based optimization is used. The technique was validated in the laboratory and applied to a rating assessment of a 230-kV/500-MVA cable circuit. The assessed continuous and emergency ratings are helpful in improving the operation of this circuit.     

±320kV直流电缆交联聚乙烯/三元乙丙橡胶附件击穿特性

高压直流电缆接头与终端为电缆系统故障的多发点,其击穿强度为直流输电系统安全稳定运行的重要基础。文中以±320 kV高压直流海底电缆中交联聚乙烯(cross linked polyethylene,XLPE)/三元乙丙橡胶(ethylene propylene diene monomer,EPDM)附件为研究对象。首先,研究电缆及附件负荷循环耐压试验,发现附件界面为击穿薄弱环节;其次,研究绝缘材料电导率随温度变化特性对电场分布的影响规律,通过有限元仿真模拟电缆空载和满载运行时附件的温度分布与电场分布,发现最大电场出现在电缆绝缘靠近附件应力锥一侧,为29.5 kV/mm,低于附件材料的击穿场强;最后,研究界面在直流电场下空间电荷特性对电场分布规律的影响,通过电声脉冲法测试复合叠层片状样品介质界面的空间电荷及其电场分布,发现场强畸变率约为100%~200%。同材料本征绝缘匹配相比,界面空间电荷积聚对附件内部电场造成的畸变程度更严重,在后续附件提升中应更注重开发抑制空间电荷的绝缘材料。     

电力光缆线路状态检修的探索与实践

文章分析了电力光缆线路传统检修模式的不足,介绍了湖州电力局为提高电力光缆线路检修工作的针对性和有效性,降低运行维护成本,开展电力光缆线路状态检修的探索与实践.电力光缆线路的状态检修借助大量电力光缆线路检修和测试等运行数据,借鉴输变电设备状态检修管理经验,通过对电力光缆线路运行状态量的收集、汇总,进行电力光缆线路状态评价...     

基于表面温度场的电缆线芯温度在线诊断研究

线芯温度是电缆的一个重要参数,当电缆过负荷时,其线芯温度高于允许温度,使电缆绝缘加速老化,甚至造成绝缘介质热击穿。文中提出了一种基于电缆表面温度场的对电缆线芯温度进行在线诊断的方法。该方法采用红外热象仪拍摄电缆的表面热图象,可根据电缆的表面温度、结构参数,物性参数和环境温度,通过建立传热数学模型,对电缆的线芯温度进行反演计算,并与其允许温度进行比较,实现了电习温度的非接触,在线诊断。