Long-term electrical performance and life model fitting of XLPE andEPR insulated cables

The results of life tests performed on XLPE and EPR cable models are presented and discussed. The performance of the two insulating materials when subjected to electrical stress are compared on the basis of characteristic parameters derived by the best-fitting life models. It is found that while EPR is well described by linear models, XLPE data fit curvilinear life models, showing a tendency to electrical threshold. Hence the fundamental parameter for XLPE characterization is the threshold value, while the voltage endurance coefficient should be used to characterize EPR     

Accelerated aging tests for polymer insulated cables under wetconditions

The effectiveness of various aging test procedures utilized in the past to evaluate aging in polymeric cables under wet conditions is examined. It is pointed out that the prime parameters affecting the aging rate and its mechanisms are those of electrical stress, frequency, water solution, temperature, mechanical strain, and testing time duration. Any valid fixed-time or time-to-breakdown test procedure that is based on the stress/frequency acceleration concept must, therefore, be carefully specified and defined in terms of these parameters     

高压XLPE电力电缆绝缘老化状态评价研究进展

高压交联聚乙烯（XLPE）电力电缆的绝缘老化状态关系到供电可靠性,故电缆绝缘老化状态检测及评价方法的研究意义重大。对于高压电缆的绝缘老化状态检测及评价,国内外已有相关研究成果,文中总结了目前常用的高压电缆绝缘状态离线、在线检测及评价方法。离线检测手段准确性高,但不适于对在役电缆进行大面积取样检测;在线监测的环境干扰因素太多,存在的干扰会对监测结果产生影响,有一定检测局限性,且缺乏大量的实验数据支撑;而对于电缆绝缘老化状态评价方法,尚未有广泛认可的评价标准和体系。文中在总结概述现有方法的基础上,提出了目前电缆老化绝缘状态综合评价方法存在的难点及未来电缆绝缘老化评价研究可提升的方向。     

Severe degradation of the conductor screen of service and laboratory aged medium voltage XLPE insulated cables

The main purpose of this paper is to show the strong correlation between corrosion of the metallic aluminum conductor and the formation of interconnected cracks / voids in the conductor screen, creating initiation sites for vented water trees in service aged medium voltage XLPE cables. The results show that porous structures in the conductor screen previously reported for laboratory aged insulation systems, also develop in the conductor screen in service aged medium voltage XLPE cables. These structures can bridge the screen and serve as path for contaminants and corrosion products from the aluminum conductor and initiate water trees. A prerequisite for the formation of such structures is the presence of liquid water at the interface between the conductor and conductor screen causing corrosion. The initiation site of such structures has been identified, and is likely caused by environmental stress cracking (ESC). Initiation sites were determined in all cables, but porous structures in the conductor screen were only observed in the cable suffered from service failure, where liquid water had entered the cable conductor between the strands. Severe degradation of the XLPE insulation was observed at the initiation sites for water trees growing from these structures.     

Long-term characteristics of XLPE cables

To study the long-term characteristics of XLPE cables installed in free air and in water, aging tests were conducted under various testing conditions using XLPE cables with both 3.5 mm and 6 mm insulation. From the Weibull plots of lifetime distribution under the voltage stress E_L as the minimum breakdown strength, the minimum value of time to breakdown t_L under the constant voltage was estimated. The results of accelerated aging tests of XLPE cables installed in free air demonstrated that the V-t characteristics of XLPE cables could not be described by the conventional inverse power law (t ∝ V⁻ⁿ) with a single constant life exponent n. Based on the microscopic observation of a sliced insulation removed from XLPE cables, it was concluded that bow-tie trees with longer tree length observed in cables tested in water were caused by the moisture from outside, whereas the trees in cables tested in free air were caused by the residual moisture originally existing in the insulation. The breakdown strength of the aged cables tested in water increases through cable drying. However, it does not recover to the original values.     

交联聚乙烯绝缘电缆的新应用

本文就ABB公司XLPE绝缘电缆的一系列新应用进行简单介绍,它的特点是采用电缆作为绕组,并就电缆做绕组产生的一系列与传统电磁装置的许多不同特性进行分析比较。通过比较,可以认为XLPE绝缘电缆绕组的新型电力设备将是21世纪电力的主流产品。     

高压交联聚乙烯绝缘电缆的选择

本文对高压交联聚乙烯绝缘电力电缆的有关问题进行了讨论 ,对电缆导体、金属屏蔽层或金属护套、外护套等选择进行了比较 ,也对金属屏蔽层的接地和敷设方式进行了分析和讨论。     

Partial discharge pattern recognition by neuro-fuzzy networks in heat-shrinkable joints and terminations of XLPE insulated distribution cables

An identification technique is described, based on a developed adaptive fuzzy logic network, that enables the recognition of partial discharges (PD) generated by different defects in heat-shrinkable joints and terminations of XLPE insulated power distribution cables. It is shown that different sources of PD can be identified on the basis of fuzzy rules applied to a selection of parameters derived from PD-pulse phase and amplitude distributions. A comparison with other PD pattern recognition techniques based on traditional neural networks is presented and discussed.     

Development of XLPE insulated DC cable

This paper describes the development of dc XLPE cable. Through a series of material investigations, an XLPE compound containing highly purified special filler was developed. To check the dc insulation performance of the cable insulated with this new material, a prototype cable with 9 mm insulation thickness was manufactured. It was confirmed that the performance of the prototype cable was excellent. Based on the study of the prototype cable, a 250-kV dc cable with 20 mm insulation thickness was designed and manufactured. Through a series of voltage tests, excellent dc insulation performance of the developed cable was verified.     

The world's first use of 500 kV XLPE insulated aluminium sheathedpower cables at the Shimogo and Imaichi power stations

The world's first practical applications of 500 kV XLPE (cross-linked polyethylene) cables took place in 1988 at the Shimogo power station of the Electric Power Development Co. Ltd., and the Imaichi power station of the Tokyo Electric Power Co. Inc.. Research and development work on the cables had been conducted since 1982. Efforts were concentrated on quality control to remove contaminants from the insulation and to extrude the very thick-walled insulation without any defects. Insulation performance tests, including long-term aging, confirmed that the 500 kV XLPE cables and the terminations were highly reliable with superior initial and long-term performance. The installation was completed successfully, and the cables are now in satisfactory operation at both power stations. The cable routes, design of the cable and termination, cable manufacture, results of the insulation performance tests, installation work, and site test are discussed     

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     

交联聚乙烯电缆局部放电检测技术

主要探讨用高频宽带电磁耦合法检测交流聚乙烯绝缘电力电缆的局部放电。运用数学中的分形学自相似和分数维原理,提出全新概念的交联聚乙烯绝缘电力电缆局部放电在线监测、在线巡测技术。     

Development of 500-kV XLPE cables

A 500-kV XLPE insulated cable with an insulation thickness of 27 mm has been developed for long-distance transmission lines. Basic studies on the 500-kV XLPE cable have shown that contaminants in the insulation may determine electrical performance. This hypothesis is justified by the good correlation obtained between statistical estimations of the size of the largest contaminant in the insulation and electrical characteristics of full-size cables. Voltage-withstand and long-term tests have confirmed design values for minimum breakdown stress, ac and impulse voltage, and degradation coefficients. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (1): 28–40, 1997     

交联电力电缆故障点的定位

本文详细介绍了用于检测交联电力电缆击穿故障和局部放电定位的方法和使用的仪器 ,以及测试线路的改进     

Study on the dielectric characteristics of DC XLPE cables

The DC characteristics of XLPE (crosslinked polyethylene) power cables were investigated. Cables with an insulation thickness of 2.5 mm, 9 mm, and 13 mm using either XLPE or conductive-inorganic-filled XLPE (XL-A) were manufactured, and four kinds of breakdown tests (DC, polarity reversal, impulse, and superposing opposite polarity impulse on DC prestress) were performed. A 250 kV, XL-A cable (20 mm thickness) was designed and manufactured using the results. The test results show that the XL-A cable possesses much better DC breakdown characteristics than the XLPE cable and is adequate for use in DC cables     

变频电机用交联聚乙烯绝缘电缆的发展

国内外变频电机使用量迅速上升 ,单台电机功率也逐步增大 ,我国电缆行业开始对电机绕组线进行了深入研究 ,但对于变频电机用电缆品种还没有得到足够的重视 ,因而提出应重视发展变频电源和变频电机之间连接用的电缆。本文讨论了这种电缆的工作条件特殊性 ,说明在内因和外因两方面均存在某些问题。针对这种特殊性 ,讨论了其结构改进要点以及研讨增加脉冲电压试验的合理性 ,并提出进一步制订专业标准的必要性。     

调频串联谐振装置在XLPE绝缘电缆试验中的应用

介绍一种调频串联谐振装置的原理及工作过程,并在高压交联聚乙烯(XLPE)绝缘电缆交流耐压试验中应用.     

500kV XLPE电缆在宜兴抽水蓄能电站的应用

简要介绍500 kV XLPE电缆构造及特点、耐压试验及相关分析,借鉴相关电厂成熟经验,更安全稳定地将500 kV XLPE电缆应用于宜兴抽水蓄能电站。     

交联聚乙烯电缆在线监测与检测

对我国交联聚乙烯(XLPE)电缆在线监测及检测技术的现状进行综述,涉及电缆主绝缘的在线监测(包括直流成分法、直流叠加法、低频叠加法、在线介质损耗角正切法和局部放电在线监测法等)、电缆护层的在线监测(包括接地容性电流监测、电缆护层综合监测和接地电流监测等)、电缆温度在线检测、电缆终端的红外和紫外在线检测等。对各监测手段的原理进行介绍,分析各种方法的优缺点,并对一些方法开展应用研究,提出了效果好、有实用价值的电缆在线检测方法。