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Soaking: Diminishing Returns I

March 31, 2011

Soaking I:  Diminishing Returns

Q:

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?

A:

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