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CableCURE® is a proprietary technology used to enhance the dielectric capacity of power cables and therefore improve the quality of power distribution networks. CableCURE® Technology means the technology and improvements relating to chemical restoration and treatment of insulated power cables for failure caused by water treeing. 
UtilX is the global leader in cable life-extension technologies. UtilX focuses on bringing cable system diagnostic and enhancement technologies to diverse worldwide markets. UtilX operates throughout the United States and serves international customers through subsidiaries and licensees in dozens of countries.
Dow Corning Corporation Dow Corning invented CableCURE® Restoration Technology in the late 1980s and licensed this technology exclusively to UtilX Corporation. The material is a silicone-based fluid that is injected through the strands of the cable and then diffuses into the insulation to fill voids and eliminate water trees. Dow Corning developed the original CableCURE® chemistry and process - the 011 patent.
All of our Material Safety Data Sheets (MSDS) for the fluids used during the injection projects are provided by the fluid's manufacturer. Therefore the MSDS of our CableCURE® /XL, /CB, /SD, ... are issued by Dow Corning, not UtilX nor TCI. All components are listed and nothing is hidden from the public and public security authorities.
The collaboration between TCI and UtilX started in 2000 and has been very successful ever since.
Since 1988, CableCURE® XL liquid silicon base injection technology has rejuvenated more than 24 million meters of cable worldwide. The technology is used in both the energy and telecommunication sectors.
The CableCURE® fluid today comes with:
CableCURE/XL dielectric enhancement fluid is injected into the conductor strands. The fluid rapidly diffuses from the conductor strands into the solid dielectric material (insulation). Once inside the insulation, CableCURE/XL reacts with the water in the tiny micro-voids and fills them with a dielectric oligomer, repairing the damage caused by existing water trees and other dielectric defects. CableCURE/XL retards the growth of future water trees and extends the life of even badly-aged cable by more than 20 years. The rejuvenated cable is then guaranteed for an additional 20 years.
Cables are injected with CableCURE®/XL, CableCURE®/CB, or a mixture of the two.
CableCURE®/XL is used to raise the insulation value of the cable's insulation by diffusing into the insulation and reversing the effects of water trees. CableCURE®/XL is used exclusively for URD cables and is the most common injection fluid for power feeder cables.
CableCURE®/CB does not diffuse into the insulation, but is used to displace water from the conductor of the cable and permanently block its re-entry, and fill the voids. CableCURE®/CB does not diffuse into the cable's insulation. CableCURE®/CB is typically used for larger power cables (4/0 and larger).
Mixtures of CableCURE®/XL and CableCURE®/CB are often used to provide some of both benefits.
CableCURE®/SD is injected into cable that will be treated with CableCURE®/XL. It will flush water and conductive contamination from the strands and adjacent conductor shield.
Our TCI CableCURE® services:
TCI is a Turn-key service provider - we have injected more than 180 km of power cables in Canada since 2001. Our injection Forecast is to double this amount in the next four (4) years.
THE INJECTION PROCESS In a reputable process, volume considerations are everything. Getting the maximum amount of TRULY FUNCTIONAL material into the cable's insulation is the goal. We do not use non-functional components for marketing spin, which would dramatically reduce the primary functional goal which is life extension of aged cables.
TCI uses the only non-destructive and most efficient process for achieving proper dielectric material rejuvenation:
TCI does not force fluid into the cable at pressures high enough to expand the semi-conductive conductor shield away from the conductor.
Real world performance criteria is measurable and data is readily available for cables treated with our conventional injection materials and processes, we can demonstrate real world performance. Injection technology based on the CableCURE® process and phenylmethyldimethoxysilane based materials is the most effective injection processes available. UtilX will continue to innovate fluid and process development. UtilX R&D will be targeted to respond to real market needs. Those innovations will follow conservative research and development processes.
None of the work TCI will perform over the next 20 years will erode the confidence we have earned over the last 8 years. We can use the same statement for UtilX, and change 8 by 20 years. We have the only cable injection solution with the track record and proven product history.
Our products are 100% water reactive.
We are available to provide support to our customers to explain and help understand the chemistry behind our products and other products available on the market, including fluid comparisons at the component and molecular levels.
THE INJECTION PROCESS, list of activities
Initial activities
De-energize, test and ground cable.
Flow & Pressure Tests
Treat - Low Pressure Injection
Soak Period
Diffusion Period
Description of our Injection Solution
CABLE INJECTION TECHNOLOGY & PROCESS, AN OVERVIEW
For decades, utilities have used polyethylene-insulated cables for construction of underground electrical distribution and transmission lines. The high proliferation of these types of cables is justified by their low cost, high availability and ease of installation. Improvements to the quality of the raw materials as well as better manufacturing techniques have increased the life expectancy of these insulated conductors. Other types of insulated cables such as PILC (paper-oil-lead cables) are very reliable but higher costs and environmental concerns make the option less attractive.
Earlier vintages (pre-1980) have experienced a higher than expected failure rate. Some of these failures are the consequence of inappropriate installation, dig-ins, power surges or other operating related incidents. These types of cable faults can be reduced or prevented with stringent quality controls as well as increased customer and contractor awareness.
The degradation of the polyethylene insulation used in most of these cables is by far, the single most important source of cable faults. This premature aging process is caused by a phenomenon known as water treeing.
Medium and high voltage solid dielectric cables installed prior to 1980 have experienced significant degradation in dielectric performance and reliability. While modern solid dielectric cables are likely to maintain their performance for much longer, the pre-1980 vintage cables are at or near the end of their useful lives. Over the last 20 years an alternative technology has been developed and proven in field installations, which provides a more cost effective approach than replacement of these aging circuits. A silicone fluid injection process has been developed and deployed in more than 24,000 kilometres of medium and high voltage solid-dielectric cables and has provided failure-free performance in over 99.% of the applications. The cables are recycled for at least 20 more years preserving scarce world resources.
Beginning in 1986, silicone injection entered commercial use as a material which when injected into the strands of medium and high voltage power cable provided substantial dielectric enhancement and extended reliable cable life.
WATER INTRUSION AND WATER TREES
Water trees start with imperfections (surface irregularities, voids, contaminants, etc.) in the cable insulation. They grow in all solid dielectric materials. There are different varieties of water trees. For instance, bow-tie water trees start off as contaminants or imperfections in the insulation, vented water trees (Figure 1) begin at imperfections on the surface of the insulation. Water trees grow in the presence of high AC stress (caused by imperfections) and water. These tree shaped structures are diffuse clouds of microscopic unconnected micro-voids.
There are many factors that contribute to the presence of water in cables: submergence, condensation (warm moist air ingress at terminations that condenses in cooler underground environment), residual water from manufacturing (older cable manufacturing methods), infiltration through splices, bad installation, improper storage and diffusion through insulation.
In their infancy, water trees originate from voids, contaminants and imperfections on the inner and outer surface or from the inside of the insulation layer. The degradation is similar to the performance of a steel pipe. As oxidation reduces the burst pressure of a water main, water trees reduce the AC break down (ACBD) strength of polyethylene-insulated cables. As the pressure exceeds the strength of the pipe small cracks appear and the final result is a broken water main. In underground cables, water trees are influenced by high voltage and water. As water trees grow, the ACBD is reduced. In time the electrical stress exceeds the ACBD and water trees evolve into electric trees (Figure 2). This final state of degradation is irreversible and cable failure is imminent. A fault will occur in a short period of time.
Electric trees are micro voids that are the final stage of water trees. They are the consequence of surges, electrical impulses or partial discharge that increase pressure on permeated water trees and alter permanently the insulation. Routine procedures (such as snapping a capacitive charge, bad switching procedures or inappropriate cable testing) if not performed properly may also produce electric trees. These micro-faults cannot be rejuvenated.
DIELECTRIC ENHANCEMENT
Typically AC breakdown performance increases after the injection at a rate of about 0.5% each day. Peak performance is reached after about 24 months at between 200% and 400%. The peak performance is typically very close to what virgin polyethylene cables could be expected to have and falls in the 30- to 40-kV/mm range.
The silicone treatment fluid will diffuse out of the strands where it is injected through the relatively porous strand shields and into the insulation. The heavy loading of carbon black in the strand shield makes diffusion of the silicone treatment proceed very rapidly through that layer.
Ultimate performance is realized only after the fluid has had sufficient time to diffuse through the entire width of the insulation. While the time that this takes is dependent upon the insulation thickness, the temperature profile of the cable, the morphology of the solid dielectric, and the amount of water present, peak performance is typically realized about two years after the injection is performed.
The bottom line for any Utilities involved in cable injection for some time is that since their injection process started, their customers are not experiencing as many outages. Lineworkers are not pulled off their work as often. For a fraction of the cost to replace cables, they have reversed their failure rates, and have accomplished this in a remarkably short period of time.
CableCURE® technology has been utilized in the following countries and demonstrated reliability improvements and cost savings similar to what is described above, when compared to the replacement alternative:
THE INJECTION PROCESS
Circuits are deenergized and grounded. A high-performance time domain reflectometer (TDR) is attached to the cable end through an impedance transition device (ITD). The ITD serves to streamline the connection between the TDR and the cable. This approach allows for the accurate enumeration and the pinpoint location of all sleeves (or splices) along with any other impedance anomalies.
For cable with conductors larger than 3/0, it is generally necessary to replace each splice with a special purpose injectable splice. These splices are available in a variety of designs from major global manufacturers in heat-shrink, cold-shrink, or molded varieties.
For conductors smaller than 3/0, molded splices will generally flow without modification. One common misconception is that on molded splices, the fluid must flow through the compression sleeve, which very often has a water stop. In fact, the fluid flows around the sleeve.
Once the locations of any splices are established, special injection terminations are installed. These terminations come in a wide variety of shapes and sizes to fit virtually any cable design. Dead-front and live-front devices, molded, cold-shrink and heat shrink variants are available.
Splices in URD cable will generally allow flow.
Feeder Splices are replaced.
After the injection terminations and if required any injectable splices are installed, the injection crew uses a vacuum pump to remove all of the air from the cable. A small amount of strand desiccant is injected prior to the primary silicone injection fluid to flush water and impurities from the strands.
Finally, the silicone fluid is injected at a pressure between 1 and 7 bar behind the strand desiccant. For cables with conductors greater than 3/0 the process is complete as there is sufficient volume in the interstitial spaces within the strands to sufficiently treat the insulation.
For cables smaller than 3/0, a small reservoir of fluid referred to as a "soak bottle" is left attached to the termination for 60 to 120 days depending on the thickness of the insulation and the conductor temperature. The soak bottle supplies replacement fluid to the strands at less than 1 bar as the fluid in the strands slowly diffuses into the insulation. The soak bottle design permits its connection to an energized cable. The bottle may be removed with a suitable insulating stick without an additional circuit outage where work rules permit.
SUMMARY
For Utilities involved with cable injection programs, their programs have reversed the upward trend in URD cable failures at a fraction of the cost required to replace cables. The same life-extension results have been demonstrated on cables from 5 kV to 115 kV, from conductors as small and #4 to conductors as large as 1500 kcmil, on circuit lengths which are typically 100 meters long to submarine applications where the cable is in excess of 7 kilometers long. Advancements in the art continue to be made as new material developped by Dow Corning and UtilX Corporation promise even longer life extension than the technology used in previous fluid generations.
CableCURE® Injection Process
Cable Life extension - CableCURE:
1Federal Energy Regulatory Commission (USA) 2Rural Utilities Service (USA)
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