4. November 2011 15:47
Dear Abundant Amphibian,
At our monthly staff meeting yesterday afternoon, I made the presentation on our cable rejuvenation project and I believe it was well received. I appreciate the information and PowerPoint slides that your most excellent sales representative supplied.
I did have one question asked that I did not know the answer to – what is the voltage limit of the process? I am sending an e-mail to our department director concerning our project and the benefits of the rejuvenation process in general and I would like to include the answer to that question if possible.
The highest voltage ever rejuvenated was 115 kV. As a practical matter there are not many solid dielectric cables at voltages above 115 kV that are not water-tight designs. However, if there were we would love to treat those too. You see the thicker the insulation the easier it is to treat the cable. The rate of fluid exudation, that is the rate the fluid leaves the cable, is slower the thicker the insulation. Our most technically difficult challenge is the 110 mil thickness 5 kV cables. So there really is no upper limit.
In 2012 we will be unveiling new products to deal with lower voltage cables, so we will be able to treat any solid dielectric cable – any voltage, any non-filled stranded conductor.
Any voltage – any time,
2. November 2011 21:46
Dear Wet One,
Our construction centers have posed the following questions:
1. Is the injection fluid flammable after the cable has been treated? If yes, for how long?
2. Is it safe for our crews to splice a failed cable that has been injected? What type of precautions do they need to take when working with cable filled with injection fluid?
Can you provide some froguidance?
Seeking Answers in San Antonio
Before I can answer the first question it is useful to define the word, flammable. In a practical sense flammability is meant to convey the ease with which a material may be ignited. Highly flammable materials are easy to ignite; non-flammable materials are more difficult to ignite. Flash Points are an objective measure of flammability. The lower the flash point the more flammable the material. In the United States two arms of the U.S. government provide definitions for what is flammable, what is combustible, or not combustible. You have to love the government; its two agencies promulgate inconsistent definitions. This means that when one uses the words “flammable,” “combustible,” “not flammable,” and “not combustible,” one needs to define whether they are using the Occupational Health and Safety Administration (OHSA) definitions or the definitions of the Department of Transportation (DOT) . Definitions in other countries may or may not be the same as those provided by Uncle Sam. The table nearby provides those definitions and the regulatory citations. As a practical thinker I prefer to avoid the regulatory morass and simply compare flash points. The higher the flash point the less likely the fluid will ignite in a specific field circumstance.
A liquid’s flash point is an indication of the temperature at which sufficient flammable vapors have evaporated to allow for ignition and the propagation of flame when exposed to an ignition source (spark/flame). The higher the flash point the less likely a fluid will ignite in otherwise identical circumstances.
In the second table nearby the flash points of some common substances are listed along with commercially utilized cable rejuvenation fluids ordered from most flammable to least flammable. The first four items in the table meet the DOT and OSHA definition of flammable. At Novinium we have an unwavering commitment to safety so we are loath to use flammable materials. The simple answer to your first question is – no!
Using non-flammable fluid is not the only way Novinium reduces exposure to fire and explosion hazards. A second very important way is to limit the period of time that injection bottles are connected to energized cables. The probability that a leak will occur is related to the length of time that a feed or a soak bottle is connected to a cable. Whether utilizing Novinium’s patented sustained pressure rejuvenation (SPR) or the older but improved unsustained pressure rejuvenation (iUPR), Novinium’s patented catalyst technology eliminates the need for a soak period completely. Approaches that don’t utilize Novinium’s patented catalyst technology require soak periods of 60 days or more for most 7-strand and 19-strand conductors. Utilizing Novinium technology typically reduces the exposure to leaking fluids over 60-fold. For a thorough description of all of the rejuvenation dimensions of safety including even more about flash points and flammability my colleagues, Rich and Glen provide an 89-page treatise, “A Comparison of Rejuvenation Hazards & Compatibility.”
With regard to your second question, there are indeed sensible precautions that your crews should take when working with cable filled with injection fluid. Novinium has a six-page illustrated instruction sheet, “Rejuvenation Instructions: Cutting a Novinium™ treated cable” which provides the required background and instructions. Click here to download a copy. Do not use these instructions for fluids not supplied by Novinium as additional safety precautions would be prudent for those more flammable materials.
My advice to you is to never compromise safety. State-of-the-art patented technology and non-flammable fluids for URD cables are available only from Novinium. For high temperature feeder cable applications Novinium has the only fluid with a flash point higher than the maximum operating temperature of the cable.
Practice safe rejuvenation,