Improved Understanding of Extruded MV Cable Performance Through the Modification of Existing Approval Protocols

Presented at Jicable '07.Cable users and manufacturers have an increasing wish to gain a deeper understanding of cable performance, beyond the knowledge that it simply complies with the minimum performance level defined within a standard. Although approval test protocols have served this purpose well, they do not provide the level of sophistication that is required for a detailed analysis. This paper describes many of the common shortfalls in current test protocols and advocates a number of simple modifications to procedures. These modifications will make approval test methods better able to address the more detailed discrimination being requested today

Effect of Size on Electrical Performance

This paper was presented at IEEE International Symposium on Electrical Insulation, June 2006. ©2006 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Digital Object Identifier: 10.1109/ELINSL.2006.1665249The electrical breakdown performance, either unaged or after ageing (laboratory or service), is often used as the basis for qualification of a device, design or material. Many of the features that affect these performance levels have been discussed in other documents; contaminants, propensity for water treeing, insulating and semiconducting materials. However the size of cable tested is rarely discussed. This is somewhat surprising as it has been long recognized that electrical failure is an extreme value (the Weibull distribution is a member of this family) or weakest link process. In extreme value processes the performance of the whole device is determined by the single "weakest link". Thus when more "weak links" are present the chance of failure is consequently higher: the measured performance depends on weak link concentration or size of the device. Additionally at some dimensions the thickness of the dielectric can influence the breakdown mechanism itself; especially if the thermal influences are present. This paper will attempt to discuss a number of these size related issues for both AC & impulse conditions; these will include: 1) the effect of the dielectric volume actual mechanism of failure, 2) prediction of performance on service length cables from short length laboratory tests. This has practical relevance on the selection of appropriate qualification levels which will have direct relevance to service performance, 3) the requirements for cable quality when increasing the size (thickness or length) installed

VLF/AC Withstand Testing at NEETRAC

Presented at IEEE PES Insulated Conductors Committee, Spring 2008 Meeting , St. Petersburg, Florida, March 9-12, 2008. Copyright GTRC 2008.This material is based upon work supported by the Department of Energy under Award No DE-FC02-04CH1237

On-Site Partial Discharge Assessment of HV and EHV Cable Systems

Presented at the Insulated Conductors Committee, San Antonio, Texas, October 26-29, 2008

On Distribution Asset Management: Development of Replacement Strategies

Presented at IEEE PES PowerAfrica 2007 Conference and Exposition. ©2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Digital Object Identifier: 10.1109/PESAFR.2007.4498062The components of electricity networks are ageing. It is expected that within a horizon of 15 years, the performance will deteriorate significantly, while the costs for operating the networks will increase enormously. The main problem is that a significant part of the population of the assets is installed in the same period, resulting in a highly concentrated number of failures in a short time. The currently applied replacement strategy has to be revisited, in order to accommodate the effects of ageing assets: higher maintenance costs, high failure rates, and a steep increase of capital expenditure (CAPEX).The work reported here was supported by a large number of utilities in North America and the US Department of Energy under award number DE-FC02-04CH11237

Practical Issues Regarding the Use of Dielectric Measurements to Diagnose the Service Health of MV Cables

Presented at Jicable '07.During the last decade, Very Low Frequency (VLF) testing for extruded distribution cables has gained interest among the North American utilities. The increasing interest is evidenced by recent research publications and discussions inside the expert community in which standards are being proposed and continuously discussed. While there is a general consensus as to the meaning of insulation dielectric properties, many open issues still remain for discussion in order to produce a more accurate evaluation. Consequently, this paper will discuss a number of the practical issues that arise when making these measurements at VLF on field aged and non-aged cables, particularly Tan δ measurements. The discussion is based on data from laboratory experiments and field testing.The work reported here was supported by a large number of utilities in North America and the U.S. Department of Energy under award number DE-FC02-04CH11237

Validating Cable "Diagnostic Tests"

Presented at Jicable '07.Diagnostic Techniques are increasingly employed by utilities to manage their infrastructure assets. These are sophisticated techniques being applied to complicated and diverse real world networks. Consequently there are many concerns that these techniques a) are not accurate and b) damage the system by, at the very least, robbing other areas of vitally short resources. Thus there is a compelling need to develop and deploy simple and robust analytical techniques that can address these problems. These evaluation approaches would then identify the effective programmes such that support could be strengthened to these areas, whilst minimizing the resources deployed on approaches that are ineffective

How Accuracy Impacts the Economic Benefit of Cable Diagnostic Programs

Presented at Fall 2007 PES-ICC Meeting.This material is based upon work supported by the Department of Energy under Award No DE-FC02-04CH1237 and CDFI

Tan Delta Testing: Effects of Terminations

Presented at IEEE PES Insulated Conductors Committee, Spring 2008 Meeting, St. Petersburg, Florida, March 9-12, 2008. Copyright GTRC 2008

Superhydrophobicity in Power Applications

Presented at the Insulated Conductors Committee, San Antonio, Texas, October 26-29, 2008