CableCURE® Process And TechnologySource: UTILX Corporation
Proven Performance in Underground Power Solutions
Test, Treat, or Replace Your Underground Cable
The CableCURE® Warranty The CableCURE process is simple and elegant ... as all great ideas are. The simplicity of the process is the source for its cost-effectiveness. You can learn more about the CableCURE process on this page, but first let's look at why underground cable needs CableCURE technology. The predominant cause of failures in underground polymeric cables is water treeing. The diagram below will help illustrate what a water tree is exactly.
A. The violet-stained region in the microscopic view of the cable sample is a water tree, which spans the entire thickness of the insulation. The water tree is a diffuse structure of microvoids (generally unconnected, Swiss cheese-like holes) in the polymer. As the cable nears the end of its reliable life, electrical trees begin to grow from this water tree. Once an electrical tree starts growing, the cable will fail.
B. The inset shows an expanded view of an electrical tree.
C. Unlike the diffuse structure of the water tree, an electrical tree has discrete channels, so it's easy to tell the difference between them.
THE CableCURE PROCESS
|STEP 1: DIAGNOSIS. We apply a series of diagnostic tests before we inject CableCURE fluid into the cable. These tests assess the condition and ability of the cable to support the required flow and pressure. We also evaluate the condition of the neutral.|
|STEP 2: INJECTION. After assessing the cables suitability for injection, CableCURE fluid is injected into the cable through an injection elbow, as shown at the right.|
|STEP 3: FLOW-THROUGH. Depending on conductor size and length, CableCURE fluid will take 30 minutes to 30 hours to flow through the cable. You may energize the cable during this time, so your customers will experience little, if any, disruption in service.|
|For 600-amp applications, a special flow-through sealing kit converts industry standard splices into flow-through splices. The sealing kit, comprised of a flow-through connector, includes a proprietary sealing strategy that allows fluid to flow through the splice without encountering the splice body with fluid or fluid pressure (see photo at left).|
|STEP 4: VACUUM. A vacuum is applied to a live-front injection adaptor at the far end of the cable. This hastens the progress of the fluid through the cable and assures a complete fill. When the fluid arrives at the end of the cable, the vacuum tank is removed.|
|STEP 5: POLYMERIZATION. The CableCURE XL fluid rapidly diffuses from the strands into the insulation, where it polymerizes with the water in the microvoids and fills them with a dielectric fluid. Since the molecules of the resulting dielectric fluid are much larger than water molecules, they lock into place, retarding the growth of future water trees.|
|For cable 4/0 in size and larger, no soak period is required. For smaller cables, a feed tank is left in place for a few weeks or months (depending on cable size) to allow the necessary amount of fluid to be absorbed into the insulation. Here, the feed tank is connected to an Elastimold® injectable elbow.|