June 27, 2005—The CableCURE silicone injection technology offered by UtilX promises to deliver significant savings for utilities faced with the failure of certain underground transmission cables, says UtilX. This process can repair degraded dielectric insulation and extend the life of existing cables at a fraction of the cost of digging up and replacing them.
UtilX Vice President of Engineering William R. “Rick” Stagi explained that the solid polyethylene dielectric insulation used for many underground distribution and transmission cables from the late 1960s to the mid-1980s suffered from an unexpected accelerated aging or degradation process in the presence of water even at the molecular level. The degradation results in the development of microscopic “water trees” in the insulation, which then leads to the failure of the insulation.
Cable manufacturers corrected this problem in newer cable, but billions of feet of older cable remain buried and are prone to premature failure, Stagi said.
The UtilX process involves injecting a special fluid along the strands of the cable. The cable has to be taken out of service during the injection process, which can take up to several hours, but can be re-energized immediately afterward.
The fluid then slowly diffuses along the water trees in the insulation of the energized cable. When it contacts molecular level water, it polymerizes with the water to form a new material that essentially stops the water tree growth and serves as a strong dielectric to repair the insulation.
For more information, visit the UtilX Web site.
