Prioritizing reliability for underground distribution

US domestic power utilities are faced with over 600000 kilometers of solid-dielectric underground cables, virtually all of which do not meet the reliability standards required of a twenty-first century economy. Diagnostic testing methods are being developed and commercialized that are intended to prioritize the 600000-kilometer cable replacement effort. Over 90% of the pre1980 vintage cables are single-phase underground residential distribution (URD) cable. An economic model is presented that allows an objective comparison of any testing technique and the alternatives, which include replacing the suspect circuits or using commercially available life-extension technologies. Available diagnostic technology is not an economically viable option for URD cables. An alternative computer-based tool is now available that aids in the prioritization efforts at a small fraction of the cost of performing diagnostic testing. The tool provides a strategic reliability analysis (SRA), which allows the mining of the utility's own data to definitively answer the critical strategic questions.