Size Does Matter (but so do shape, rigidity and polarity)

In my December 29, 2010 post at … 

Crazy-Competitor-Claims

Wonderer in the Wilderness inquired …

3.  Isn’t it better to have a 100% reactive fluid?  I understand that not all of the Novinium fluid components are water reactive.  When all the fluid components are reacting with water, it seems like you should get better cable rejuvenation.

In this post I will provide a more comprehensive answer.  We learned from the abbreviated answer that water reactivity per se is a short-lived phenomenon and that the data provided by those who now croak of the importance of water scavenging confirms this is so.  The water reactive functionality is gone in about two months for a 1/0 AWG conductor, it would last somewhat longer in bigger cable, but shorter still in a No.2 AWG cable.  For decades-long life extension water reactivity over a couple of months has little direct impact.  If water is not kept out by chemical reaction, how is it excluded?  “Excluded” is such an absolute term and the second law of thermodynamics precludes such an absolute, but we can greatly reduce the quantity of water by preferential solubility.  All of the components of all rejuvenation fluids are more soluble in the polymeric insulation than water.  There is a finite amount of space between the amorphous polymer chains that constitute cable insulation.  If those spaces are preferentially filled with rejuvenation fluid, there is that much less room for water.  Furthermore the chemical properties of well chosen rejuvenation components can mitigate water damage even if there is some water present.  Water is such a small molecule with such a large diffusion coefficient (See the nearby Figure.) that even if one could temporarily react with all of the water in the cable it would be back in a few short days.  For a comprehensive understanding of the molecular thermodynamics of water in cables see …

IEEE-Molecular Thermodynamics of Water in Direct-Buried Power Cables

The real goal of including water reactivity in the formulation is to increase the size of the silane treatment components so that they diffuse slower once they get into the insulation. Slower diffusion means that the rejuvenation component is slower to exude out of the cable into the soil where it obviously provides no benefit.  The suggestion of those who croak for 100% water reactivity is that if it doesn’t react, then it will exude.

Nothing could be further from reality.  The only way to know how fast a component will migrate and exude from a cable is to make measurements of diffusion and solubility.  At Novinium we have made thousands of such measurements.

Does size matter?  Sorry boys, but yes it does.  In general, the bigger the molecule the slower it diffuses, but size is only one of several parameters.  In the Figure nearby I show to scale, two-dimensional representations of the non-catalytic components used in all URD treatment fluids.  (I will deal with catalyst in a separate post and with feeder fluids in yet another post.)  I have arranged the components from the fastest to diffuse to the slowest to diffuse.  At first glance, the bigger the molecule the slower it diffuses, but that isn’t always the case.  Included in the Figure alongside each molecular model is a short name for the component, its molecular weight (the absolute mass of a single molecule), and the approximate diffusion coefficient at 55°C (cm²/s).  Some of the other factors that affect diffusion include the shape of the molecule, the flexibility/rigidity of the molecular structure, and its dipole moment (or internal charge imbalance).  For a molecule to move through the insulation polymer it has to squeeze through very small spaces.  Side chains and protrusions such as those designed into many of the molecules we use at Novinium improve longevity versus the more svelte molecules used in the first generation of technology. 

Ferrocene is an example of a small molecule with an anomalously small diffusion coefficient.  Its rigidity and shape provides its anchor.  KV10 stays in the cable much longer than suggested by its 10^-8th diffusion coefficient.  KV10 was designed with two long carbon-chain arms, which are highly soluble in the insulation polymer, to anchor it in place and reduce what cable manufactures that use KV10 call "sweat-out."  PMH6 has been in use for over two decades and enjoys long life in a cable.  Any component below PMH6 lasts even longer.  The smaller the diffusion coefficient, the longer it sticks around.  The five bottom components are the non-water reactive components, but they enjoy the longest life.

Exposing the truth,

Thermonuclear

Crazy Competitor Claims

Dear Thermonuclear Bull Frog,

I recently attended a webinar on cable rejuvenation presented by another firm and need to ask some questions:

1.    How can Novinium get the same cable life extension without a soak period?  It would seem to me that Novinium puts less fluid into the cable than one would get with a soak period.

2.    The ’840/’841 patents prevent anyone from using a fluid that diffuses into the insulation quickly.  Do Novinium fluids infringe on those patents?  Won’t a fluid with faster diffusion and reactive fluids lead to faster and better treatment of the cable?

3.    Isn’t it better to have a 100% reactive fluid?  I understand that not all of the Novinium fluid components are water reactive.  When all the fluid components are reacting with water, it seems like you should get better cable rejuvenation.

4.    I see that Novinium uses an acid catalyst in their fluids.  Won’t this acid damage the cable, be dangerous to handle, or cause environmental problems?

5.    A new fluid, DMDB, has been introduced.  Will this improve injection performance on my URD cables?

Wonderer in the Wilderness

Dear Wonderer-

Wow, five questions in one inquiry!  That’s a record for this frog.  I like prolific questioners Mr. Wonderer, but some in my audience have short attention spans, so here is what I am going to do.  In this post, I will clarify some of your questions and provide abbreviated answers.  In the next few weeks I will expand on each of the answers.  When I do that, I will come back here and edit this post to include a link to the comprehensive answer.

First let me say that the technology utilized by the folks on the other end of the webinar was largely invented by Novinium founders.  If you want to use that technology, we will take it as a compliment that even our two-decade old ideas still have frog legs.

1.    You wrote:  How can Novinium get the same cable life extension without a soak period?  It would seem to me that Novinium puts less fluid into the cable than one would get with a soak period.

a.    Abbreviated answer:  When Novinium founders invented the technology that utilizes a soak period, we had never measured the relative diffusion rates of the catalyst and the monomer.  When we made that measurement a few years ago, we were a little embarrassed to learn that the previously chosen catalyst diffuses about six-times slower than the monomer.  This mismatch means that for a typical 15kV cable with a 1/0 AWG conductor, more than one-third of the fluid supplied to the cable prematurely diffuses out without undergoing the required condensation reaction.  We call this unfortunate condition, catalytic inefficiency.  As soon as the Novinium science team recognized this problem, we fixed it.  It turns out that in a typical 60-day soak period about one third more fluid is supplied, which just about makes up for the catalytic inefficiency.  Novinium patented our solution (U.S. Patent 7, 700,871).  Now, if you are enamored with soak periods and don’t mind the safety compromises and economic consequences that they entail, we can do soak periods too.

b.    Comprehensive answer:  See Catalytic Considerations - Component I and Catalytic Considerations - Component II

2.    You wrote:  The ’840/’841 patents prevent anyone from using a fluid that diffuses into the insulation quickly.  Do your fluids infringe on those patents?  Won’t a fluid with faster diffusion and reactive fluids lead to faster and better treatment of the cable?

a.    Abbreviated answer:  Ouch!  Suggesting to a circuit owner that a competitor is engaging in patent infringement is not a tactic we would use.  The short answers to both parts of this question are:  No and no.  The second half of the questions about size (i.e. faster diffusion) and water reactivity are addressed by question 3 below.

b.    Comprehensive answer:  See Size Does Matter.

3.    You wrote:  Isn’t it better to have a 100% reactive fluid?  I understand that not all of the Novinium fluid components are water reactive.  When all the fluid components are reacting with water, it seems like you should get better cable rejuvenation.

a.    Abbreviated answer:  No!

                                       i.    I know who suggested this to you, so let’s check out what he wrote to learn if 100% water reactivity really is important:  “The presence of the water reactive functionality phenylmethyldimethoxysilane within the insulation was confirmed by microscopic infrared spectroscopy (SiOMe band at 1190 cm^-1) through 54 days.  It should be noted that 1/0 AWG size cable has a small conductor interstitial volume compared to the volume of polymer surrounding.  Larger diameter conductor cables would be expected to have considerably more water reactive functionality present for dielectric enhancement over a longer period.”  [Don Kleyer & Wayne Chatterton, The Importance of Diffusion and Water Scavenging in Dielectric Enhancement of Aged Medium Voltage Underground Cables, Proceedings of the IEEE/PES Conference April 1994.]

                                      ii.    Allow me to translate.  The water reactive functionality is gone in about two months, but it would last somewhat longer in bigger cable, but shorter still in say, a No.2 AWG cable.

                                    iii.    For decades-long life extension, it is quite a stretch to suggest that water reactivity over a couple of months is critical.  But, if you want to believe what the author says now, rather than what his experiments previously indicated, we will make a special 100% water reactive fluid for you.  You see, Novinium has a patent (U.S. Patent 7,611,748) on a process of tailoring the fluid formulation to your unique conditions.  We will make a special brew just for you.  We can name it Ultrinium™/WC.  You might think that “WC” are the initials of the water reactivity proponent, but it stands for Water-reactive Confusion.

b.    Comprehensive answer:  See Size Does Matter.

4.    You wrote:  I see that Novinium uses an acid catalyst in their fluids.  Won’t this acid damage the cable, be dangerous to handle, or cause environmental problems?

a.    Abbreviated answer:  I notice that you use an acid in your salad dressing – vinegar.  I notice that you squeeze acid on your fish – lemon juice!  I think the webinar presenter is jealous of our U.S. Patent 7,700,871. We use less than 0.3%, less than 3 parts per thousand of a very large acid molecule called DDBSA.  The acid part of the large DDBSA molecule is 1 part in 332.  In other words the concentration of the acid proton is about 1 part in 111,000!  That’s like putting a teaspoon of vinegar in your bath water.  So no, there is no issue.  The same cannot be said of titanium(IV) isopropoxide (TIP), which is the catalyst used in the two-decade-old technology at a level of 2 parts per 1000.  TIP catalyzes the methanolic corrosion of aluminum.  TIP doesn’t taste good on salad or on fish either.

b.    Comprehensive answer:  The dilute acid will not damage the cable.  It has been deployed in millions of cable feet.  The dilute acid is not dangerous to humans or amphibians.  The acid catalyst enjoys profound benefits.  See Catalytic Considerations - Component I and Catalytic Considerations - Component II to learn more.

5.    You wrote:  A new fluid, DMDB, has been introduced.  Will this improve injection performance on my URD cables?

a.    Abbreviated answer:  No way!  Did the guy actually suggest that?  The active portion of DMDB is diluted by the presence of two 4-carbon alkoxy groups that serve no purpose other than to mitigate the aforementioned methanolic corrosion issue.  Fully two-thirds of the fluid is lost even before suffering the catalytic inefficiency of 60%!  Without a multi-year soak period, one could not hope to get enough DMBD into a URD-size cable to provide multi-decade life.  Rather than diluting the product to solve the corrosion problem, the other guys should switch to an acid catalyst.  Oops, they can’t, because we invented and patented that.  (U.S. Patent 7,700,871)

b.    Comprehensive answer:  See DMDB Doubts

Come out of the wilderness into the light.  The truth is well documented.  I don’t mind setting the record straight – that is what I do for a living.  I am not above having a little fun myself though, so I would like to ask a favor of you.  Wonderer, I would like to plant a question for you to ask the next time you participate in a wilderness webinar:  "Why was Novinium the only firm to participate in NEETRAC’s side-by-side rejuvenation test?"  All rejuvenation vendors were invited.  Instead of casting stones in webinars they could have put their technology directly against the technology leaders.  Here is the answer relayed by NEETRAC in a project conference call:  "[The invited supplier] chose not to participate citing 'business and commercial reasons.'”  Satisfied?

Concluding Crazy Competor Claims,

Thermonuclear

P.S.  I decided to create a whole new category within my blog to address Crazy Competitor Claims.  It will be like a rejuvenation myth busters!  I will print all civil responses from other rejuvenation suppliers, if they want to engage in a public debate on the merits of the various technology choices.  The other guys are big fans of mine; they visit this blog all the time.  I suspect they will cite “business and commercial reasons” for not engaging in a transparent dialog.

How long does rejuvenation fluid stay in the cable?

Dear Froggy,

How long do the silanes stay in a cable when they are injected?  What is the concentration of the resulting siloxanes across the radius of the insulation?

Alaskan Amber

Dear Amber-

Every single cable is unique.  First there are hundreds of possible geometries including different conductor sizes, three different strand compactions, different insulation polymers and thicknesses, jacketed and unjacked, to name a few.  On top of that there is the thermal profile of soil in which the cable is buried.  The difference between the soil temperature at one meter in depth between Alaska (Cryic soils are light blue in color in the image nearby from the U.S. Department of Agriculture.) and Arizona (Hypothermic soils are the orange color.) is about 20°C.  That 20°C makes a difference of about a factor of three on how fast the fluid permeates from the cable!  The cooler temperature in Alaska makes it easier to obtain multi-decade life extension compared to a similar cable buried in the Arizona desert.  Finally each cable is loaded differently and hence its operating temperature and temperature profile is entirely unique.  In the video, nearby, my collegue describes one of the infinite number of cases to illustrate the general idea.  Novinium has done thousands of such simulations in order to arrive at the formulations for its Ultrinium line of products.

At Novinium we use a patented process (U.S. Patent 7,611,748) to tailor the chemistry to the unique circumstances of each circuit owner and indeed to each cable.  No other firm in the world can tailore formulations to optimize performance.  Novinium does not ignore the three-fold difference between Arizona and Alaska.

Longer life through technology,

Thermo

Electrical Treeing and the Principle of Parsimony

Dear Thermo,

A representative of a certain off-line partial discharge testing firm is saying that injection can cause electrical trees and faults.  His premise is that the water tree is superimposed over the electrical tree and thus grades the electrical stress around the electrical tree.  By curing the water tree, the electrical tree is unleashed to grow to a fault. Basically the water tree acts like a barrier.  This is the first I have heard of this, and on the surface the notion seems outlandish.  What would the Frog say?

Alarmed in Atlanta

Dear Alarmed-

I heard that one too at an ICC meeting several years ago.  I’m surprised anyone is still croaking that tune.  The principle of parsimony that underpins all of science is that the simplest explanation, requiring the fewest assumptions is most likely to be right.  The reason you find the notion outlandish is because of this principle.

Let’s review the facts and two possible explanations.  The annotated images nearby (taken from the Spring 2004 ICC meeting minutes, Cable PD Facts – Field Experience, M. S. Mashikian) illustrate a beautiful water tree and two equally as attractive electrical trees astride the water tree, near its base.  The author is suggesting with the blue arrows that the electrical tree avoids the water tree in its growth pattern.  This suggestion is bizarre for two reasons.  First the electrical trees are clearly associated with the water tree.  The alternative explanation, that they sprung up there randomly would require the “willing suspension of disbelief” to quote a former New York Senator and now Secretary of State.  (It’s true that she was wrong, but she was politically motivated.  I, on the other hand, seek only truth and understanding.  Amphibians would make poor politicians, because we simply call them as we see them.)  Secondly, upon closer inspection both electrical trees have a substantial branch that heads right into the water tree – just the opposite of what is being suggested.  There is no doubt that the water tree alters the electrical field in its neighborhood.  For every location where the field is concentrated there has to be a neighboring location where it is less concentrated.  Electrical trees grow where the field is most concentrated.

It is common knowledge that water trees normally precede electrical trees.  It is possible to induce electrical tree growth before the presence of water trees, but that takes a great deal of voltage.  This, of course, is precisely what the off-line PD guys do – use a great deal of voltage.  Except for the folks at this single testing firm, experts agree that water trees are a leading cause of electrical trees.  In order to claim that water trees somehow moderate the fields around electrical trees we would have to ignore all of the evidence to contrary. 

What does happen when silicone fluids react with and displace the water that is associated with electrical trees?  A thorough answer is available from the CIGRÉ Canada, Conference on Power Systems, Vancouver, October 17-19, 2010, paper “Cable Rejuvenation Mechanisms: An Update” at …

www.novinium.com/pdf/papers/Cable_Rejuvenation_Mechanisms.pdf

In short, the poor dielectric properties of the water in the water tree are replaced with the superb dielectric properties of silicones and tree retardant organics.

Why would anyone suggest such a bizarre explanation?  Could it be that the superior economics of rejuvenation compared to diagnostic testing are limiting the growth of the firm that is making the claim?  Check out “Diagnostic Testing of Stochastic Circuits” from the March/April Edition of IEEE Electrical Insulation Magazine for a complete analysis.  That paper is available at …

www.novinium.com/pdf/papers/Diagnostic_Testing_of_Stochastic_Cables.pdf

So, Alarmed in Atlanta, use the principle of parsimony and the available evidence to determine if electrical trees are moderated by the presence of water trees or if they are caused by water trees and exasperated by the application of voltage two and a half times greater than operating voltage.  

Parsimoniously yours,

Thermo