by Thermo 15. April 2011 22:21
Soaking II:  Safety First
 
Dear Greatest of Soakers,
 
It seems odd to me that for one who spends so much time soaking herself, that soaking cables is anathema to your firm’s culture.  When is it appropriate to soak a No.2 compressed URD cable?  If I do soak, for how long should I soak?
 
Geometrically constrained,
 
Alaskan Amber
 
Dear Amber-
 
I provided a first installment of my thoughtful answer to your question in “Soaking:  Diminishing Returns I.”  In that first post, I drove a stake into the heart of the myth that Novinium never soaks, and I provided the background to explain why it is seldom necessary to do so.  In this second post I will explain why soaking is so very dangerous when performed the old way.
 
I could explain the safety issue in my own pithy way, but instead I copy below the words of Messrs. Stagi and Steele of UTILX Corporation.  They were granted U.S. Patent 7,704,087 about one year ago.  The patent is titled, “Check Valve for Charge Tanks.”  They have undoubtedly experienced the dangers posed by soaking.  I assume those experiences motivated their invention.  To wit (beginning on column 1, line 45) …
 
The fluid is commonly injected into underground cables from a fluid feed line, which is connected to a fluid feed tank, at the injection termination.  When fluid is injected into the cables at the injection port of the injection terminations, it is assumed that the fluid flow is only in one direction, flowing from the feed tank to the cable. However, as the cable fills and the fluid system begins to stabilize, temperature changes that occur inside the cable or outside in the environment around the feed tank can cause the pressure of the system to fluctuate.  The pressure fluctuations can lead to instances where the pressure inside of the injection elbow is greater than the pressure inside of the fluid feed tank. At this point, fluid flow would reverse, moving from the injection elbow back into the fluid feed tank.
The fluid that travels in the reverse direction, out of the injection elbow, carries contaminants from the cable to the feed tank. These contaminants can be conductive or semiconductive, effectively reducing the insulating value of the remediation fluid in the fluid feed line that separates the energized cable from the feed tank and a conductive pathway can be formed.
 
I don’t always agree with the gentlemen from UTILX.  Lacking an amphibian influence, they seem to me to be prone to error, but this time they have eloquently defined the issue.  Fluid can flow backward through the feed tubing during the soak period.  An energized tube and feed tank may flash to ground, may start a fire or worse yet an explosion, and, if anybody is nearby, the unfortunate event might injure or even kill them!  At Novinium we are not willing to take those kinds of risks.  I hope my colleagues at UTILX implement their ‘087 invention before there are any new events.
 
As mentioned in my last post, Novinium can and does greatly mitigate these risks in live-front applications with a piece of proprietary technology called an HVFI or high-voltage fluidic-interface.  Click here to view a HVFI test report, which includes a detailed description of how it works.
 
If you really, really want to soak in dead-front applications, my mechanical engineers and I will develop a system that is much safer.  Of course, using non-flammable Novinium fluids helps a lot, but we can do even better.  When you see how a frog solves this problem, you will see elegance embodied.  Stand by for more on this subject.
 
Safety First,
Thermo

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Operational Considerations | Safety Matters

by Thermo 31. March 2011 16:23

Soaking I:  Diminishing Returns

 

Dear Greatest of Soakers,

 

It seems odd to me that for one who spends so much time soaking herself, that soaking cables is anathema to your firm’s culture.  When is it appropriate to soak a No.2 compressed URD cable?  If I do soak, for how long should I soak?

 

Geometrically constrained,

Alaskan Amber

 

Dear Amber-

 

You ask more questions than any of my other numerous fans.  I like that, except I have been told that some find the questions and the answers too technical.  My response to those critics is to ask your own questions.  If you ask a simple question, I will provide a simple answer.  This Amber guy is cool, his question is appropriate, and a proper answer it is going to require two posts.  Here is the first …

 

I can see why you might have been misled to believe that I am anti-soak, but that characterization is unfair.  Let’s set the facts straight:

 

1.   Novinium has a pile of patents that make soaking unnecessary, even for multi-decade life, for all but the most geometrically constrained cables.  I will define “geometrically constrained” later.  The following technological advancements, which I have expounded upon in past blogs, mean that even without a soak, Novinium technology will last longer than the two-decade old approach used by less enlightened purveyors of rejuvenation:

a.   Catalyst improvements were chronicled in Catalytic Considerations I and Catalytic Considerations II.

b.   Novinium Voltage Stabilizers are not present in older approaches.

c.    Our ultra-violet package, which retards the formation of electrical trees was laid out in “To UV or not to UV.”

d.   The tremendous power of effective anti-oxidants present only in Ultrinium™ brand fluids was described in “AO, AO … its home from work we go.”

e.   Chain Entanglement” dramatically slows the exudation of treatment fluid from the cable and is another patented Novinium innovation.

f.     The “Really Long Term Life” afforded by still another patented Novinium innovation delivered by an ultralow permeability component.

2.   The folks at Novinium invented soaking over two decades ago.

3.   Novinium does soak cables under certain circumstances.

 

We do consider soaking as a last resort, however, because soaking has two drawbacks.  First, and in order of importance to us, there are safety compromises associated with leaving a hydraulic connection to an energized cable for a long period of time.  I enumerated these risks in my post:  Greatest Rejuvenation Risks.”  For live-front applications, Novinium can greatly mitigate these risks with a piece of proprietary technology called an HVFI or high-voltage fluidic-interface.  Click here to view a HVFI test report.  Second, there are economic costs associated with a soak period.  In short, a soak bottle with an associated capital cost must be deployed for the duration of the soak period and the injection team has to be redeployed to the site to remove said soak bottle.

 

Despite these challenges we occasionally resort to soak periods.  The very first consideration is whether the cable to be rejuvenated has a severely constrained geometry.  The “Draft Guide for Rehabilitation and Rejuvenation of Extruded Dielectric Cable” defines constrained geometry in general and severely constrained geometry in particular as follows:

 

“When the available volume of fluid that can be held in the strand interstices at atmospheric pressure is less than the optimum quantity of fluid to treat the cable, the cable is said to be a constrained geometry cable.  Figure 3-1 [below] shows the three realms of geometry for round (or concentric), compressed, and compact strand cables, namely unconstrained (greater than 20 kg/km), moderately constrained (<20 kg/km and >10 kg/km), and severely constrained (<10 kg/km).

 

In practice severely constrained cables are those with conductors of 7-strand and compact 19-strand construction.  If your cables do not have severely constrained conductors, four decades of life extension are possible without resorting to soak periods.

 

At Novinium we routinely employ soak periods on severely constrained geometry cables for high value circuits with live-front terminations.  Submarine cables provide an example of such high value circuits.  These cables can require 7-figures to replace, so the incremental cost of providing a soak is justified.  Can Novinium make soaking safe in the dead-front applications typical of residential distribution cable?  To answer that question check out my subsequent posts in this series:

 

Soaking II:  Safety First

 

Unconstrained by old paradigms,

Thermo

by Thermo 9. June 2010 20:54

Biggest Risk is Electrical

Dear Soggy Froggy,

What are the greatest risks associated with rejuvenation of medium voltage power cables?

High and Dry in Denver

Dear Dry-

It is true that my beautiful wet skin is a disadvantage near electricity.  That is why I let my journeyman lineman colleagues do most of the work.  I am the brains and the beauty behind them.  Click on the video link below where I demonstrate the greatest risk of rejuvenation – and don’t try this at home.

Rejuvenation is inherently safer than replacement.  When rejuvenating cable the electrical risk is the biggest risk by far.  For a thorough description of all of the dimensions of rejuvenation safety, including even more about electrical contact, my colleagues, Rich and Glen provide an 84-page treatise, “A Comparison of Rejuvenation Hazards & Compatibility.” That tome is available on-line at:  www.novinium.com/pdf/papers/Rejuvenation_Hazards_Analysis.pdf.

From that document I have copied the graph below.  Don’t worry there will not be a quiz and you do not need to pull out your reading glasses.  The risks are enumerated and categorized in the aforementioned tome, and the risk identified as “1.1” is the electrical contact risk.  You will find 1.1 in the upper-right-hand corner of the figure.  All of the other risks pale by comparison and lie below and to the left of the electrical contact risk.  The scales are logarithmic, so differences in risk assesments are larger than they appear.

Patented Novinium technology reduces exposure to this risk in several ways.  First the period of time that injection bottles are connected to energized cables is considerably less than with older approaches.  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 unsustained pressure rejuvenation (UPR), 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 times. When UPR is utilized Novinium also uses patent pending technology to mitigate the probability of injection port flashover.  The picture nearby shows a low amperage laboratory flashover.  The mitigation technology is called a reticular flash preventer or RFP.  This issue and the solution are described in some detail at ...

http://www.novinium.com/pdf/papers/Advancements_in_200-amp_injection_elbows.pdf.

My advice to you is to never compromise safety.  State-of-the-art patented and patent pending technology, soak-free injection processes, and RFP flash-over prevention are available only from Novinium and our partners.

Minimize your exposure,

Thermo

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