Merry Masters

Oh festive frog-

It was a pleasure corresponding with you this year, toward a better understanding of cable rejuvenation. I also appreciate all the material you provided regarding cable testing.

I wanted to take this opportunity to personally wish you and your adoptive family a Merry Christmas and a healthy and happy New Year.

Emily

Dear Emily-

Thank you for the kind sentiments. I am hopeful that your holiday season will be filled with great times with those who you love. I’ll take this opportunity to wish all of mankind and creature-kind a wondrous holiday season and a prosperous 2013.

A glance at our Novinium Christmas tree reveals elements that you would expect to see.  Presents donated by our masters going to foster children to brighten their holidays. Unblinking white lights symbolizing electrical reliability delivered with unrivaled craftsmanship. Candy canes to satiate the sweet tooth for all those Novinium masters who were good boys and girls. Dennis, no candy cane for you until you quit smoking – because we love you.

A closer examination, however, reveals ornaments fashioned out of power cables. The cables are of many constructions and from all over the world. An even closer examination reveals that the tree-top star is fashioned from the fanned-conductor-strands of a feeder cable. You might think that our star is kind of cheesy, but then being born in a manger was not a glamorous affair. I was born in a swamp! That makeshift star reminds us that it isn’t the brightness of our lights that makes us good – it is the warmth we harbor in our souls. At least to this frog, Christmas is a time to thank God for Her good will.

Green Christmas wishes,

Thermo B. Frog

Galvanic Corrosion of Neutrals

Oh greenest of greens,

My copper neutrals look a lot like you – green! I was wondering if our practice of bonding neutrals to the rebar in our vault structures might lead to neutral corrosion.

Califorrosion

Dear Califorrosion-

Yes, copper carbonate does have similar hue to me ... a touch bluer though. And like me, copper carbonate is your friend. The copper carbonate patina protects the native copper underneath from corrosion. It’s also true that bonding two metals can cause corrosion under the right circumstances. In fact this type of corrosion, galvanic corrosion, is the first mechanism mentioned in IEEE 1617™ (Paragraph 6.1 of “IEEE Guide for Detection, Mitigation, and Control of Concentric Neutral Corrosion in Medium-Voltage Underground Cables”). For galvanic corrosion to occur five conditions are required …

1. One of the two metals must be more anodic (inclined to be less negative). In your query that would be the steel rebar.

2. One of the two metals must be cathodic (inclined to be more negative). In your query that would be the copper neutral.

3. There must be a metallic connection. That would be the bonding hardware together with the neutrals and rebar.

4. There must be an environment for ions to flow. Wet soil provides such an environment, wet concrete works too, but not nearly as well.

5. Finally there has to be oxygen present. This last assumption is usually true unless the area is an anaerobic swamp.

The bottom line to your question is that the steel rebar is the anode and the copper is the cathode and hence any galvanic corrosion that does occur will occur to the detriment of the rebar. The rate of galvanic corrosion on the rebar will likely be quite slow, because concrete, even submerged concrete, does not allow for the rapid transport of ions.

My colleagues will be presenting a webinar on the subject: “Neutral Corrosion: Causes, identification & Mitigation” on September 21, 2012. To register for this learning opportunity navigate to www.novinium.com/events.aspx.

Green wishes,

Thermo

Euro-Rejuvenation

Dear Thermo,

I heard that besides the old rejuvenation technology offered by UTILX and Novinium’s improved technologies, that there is a third competitor in Europe.  Pray tell?

Hedging my bets

Dear Hedge-

There is only one firm in the world that can provide advanced Novinium technology. Today there are a total of twelve U.S. patents and their foreign equivalents. An up-to-date list of those patents is available at …

novinium.com/patents.aspx

If you want the safest and most reliable technology in the world, Novinium and our partners are the only source. Our friends down the road at UTILX Corporation offer technology invented by Novinium founders about two decades ago. Our founders are proud of their achievements, and this frog has written extensively that the performance of that old approach is quite good for non-demanding applications. Check with your risk management folks before you use that approach, however, because Novinium technology is much safer. Heaven forbid that you find yourself justifying your choice of a less safe choice to a jury. For a thorough discussion of the risks with all of the commercially significant injection approaches, check out my June 9^th, 2010 post, “Biggest Risk is Electrical.” Within that post is a link to a comprehensive risk analysis titled …

Rejuvenation Hazard Analysis 

There is a firm in Germany that offers silicone injection of power cables.  Their website is at …

www.kabelsanierung.de

Next, click on “Kabelsanierung,” which is German for cable rehabilitation. The firm is run by Professor Rudolf Wimmershoff formally at the Technical University of Regensburg. To this frog’s knowledge, Professor Wimmershoff’s rejuvenation approach has not been used too far from Bavaria. This frog cannot recommend the good Professor’s approach. He utilizes a common siloxane oligomer, which is generally used to waterproof masonry and such. The oligomer cross-links to a thick fluid resin after injection. The problem with this chemistry is that cross-linked polymers in the strand interstices can do nothing to improve the insulation’s dielectric properties, because they are way too big to diffuse into the insulation. To this frog’s knowledge there have never been any papers written to describe the post-injection performance of the good Professor’s approach. The firm’s primary businesses are transformer diagnostics and cable diagnostics.

Auf Widersehen,

Fehischlag Frog

P1816

Dear Thermo,

What is this swanky “reliability” event that Novinium is sponsoring on the Seattle waterfront in conjunction with the ICC meeting on March 26, 2012?

News in Jersey

Dear Jersey-

First I wish to object to prejudiced policy promulgated by local health authorities. Amphibians are prohibited from attending the March 26^th event to which you refer. Not that I would have any interest in the menu, I won’t eat anything unless it is still moving. The human proclivity to eat long-dead stuff is abhorrent. Forget the food; denying me access to the content is what frustrates my flippers.

IEEE P1816™ is a soon-to-be-approved, “Guide for Preparation Techniques of Extruded Dielectric, Shielded Cable Rated 2.5 kV through 46 kV and the Installation of Mating Accessories.” P1816 starts where most accessory installation instructions end. It defines the best practices for accessory installation that will lead to the highest level of reliability. The P1816 Guide was assembled by circuit owners, component manufacturers, and reliability masters like my Novinium colleagues. On March 26^th, humans who have a stake in reliability will gather to kick-off a multi-part series of webinars that will delve into the details of high-reliability craftsmanship.

Regular attendees of the Insulated Conductors Committee (ICC) will recognize the speaker’s names as authorities on the subject of reliability. Vern Buckholz, an expert on neutral corrosion, Glenn Luzzi of Richards Manufacturing, and expert on cable accessories of all types, Harry Orton an expert on sources of reliability problems, Mike Smalley of WE Energies, a P1816 Co-chair, and Bill Taylor of 3M, an expert on splices and terminations, are just some of the proficient people who will be introducing the topic and setting the stage for a year of informative webinars designed specifically to spread the gospel of reliable craftsmanship. The webinars will be designed for the craft-folk that largely determine the post installation reliability of underground cable components. Management and engineers should plan on attending too, because there will be revelations for all.

Select attendees will also be given access to Novinium’s state-of-the-art eLearning “Cable Prep Course” based upon P1816 at knovinium.com and a companion field guide. If you have not been invited to this invitation-only event, contact your Novinium sales professional at novinium.com/Contact.aspx. To see the agenda click here.

Unable to attend myself, but there in spirit,

T. B. Frog

Reflections on a TDR

Dear Thermo,

The blog entitled "Neutral Corrosion - How much is too much?" includes a waveform from a TDR (time domain reflectometer, often called a radar) that is used to pinpoint bad sections of cable neutral. The TDR is also used to pinpoint splice locations on the cable. Please provide the details of how the TDR determines the neutral corrosion and splices on the cable and how the wave form is read to tell them apart and to pinpoint their locations.

Reflective in MD 

Dear Reflective-

Step-by-step instructions for how to identify and pinpoint neutral corrosion and splices on concentric medium voltage power cables are provided in Novinium Rejuvenation Instruction 12 entitled, “Electronic Cable Diagnosis and Pinpointing.” Click NRI-12 to view the document as a PDF. The TDR sends a low voltage (10-20 volts), short wave length (1-20 nanoseconds) pulse down the cable. A portion of the wave is reflected when it encounters a change in impedance. There are four main types of impedance changes encountered along the length of a test cable.  Remember – impedance includes three elements, resistance, capacitance, and inductance. 

(1)       Instrument-Cable Interface

The first impedance change that is encountered results from the mating of the test instrument lead, an RG59 coaxial cable, which has a characteristic impedance of 75 ohms, with the power cable, which has a characteristic impedance of 8 to 38 ohms depending upon its geometry and polymer system. To minimize the reflection from this unavoidable impedance change, the masters of reliability at Novinium use a proprietary impedance streamliner. This is akin to an aerodynamic sports car versus a squarish pick-up truck. The impedance streamliner is like the smooth curves of the sports car, reflecting less of the input pulse, minimizing signal attenuation and dispersion. Attenuation is the reduction of signal amplitude and dispersion is the smearing of narrow pulse into a broader, less discrete pulse. Both are undesirable. Some reflection is unavoidable. The signature of Novinium’s impedance streamliner shown in red is superimposed upon the green signature of an older impedance technology device (ITD) in the image nearby. Untoward noise and reflections avoided improve the usability and hence the sensitivity and accuracy of the TDR.

(2)       Splice 

In the image nearby I am standing next to a very typical splice during a recent coffee break. The neutrals are all dirty as they are prone to be in a pit, but if you look carefully along the orange annotation, you can see how the neutrals are close to the conductor on the cable, then are pig-tailed together and lay farther from the conductor as they jump across the molded splice body. On the far end of the splice the neutrals again come back to intimate proximity. This change in the separation of the two signal conductors – the conductor and the neutral – changes the circuit impedance. The resistance is not significantly changed, the already low capacitance decreases with increasing distance, but that capacitance change is trivial compared to the change in inductance. The inductance and hence the impedance skyrockets as the neutrals leave the insulation shield and then plummets when the neutrals return to the cable. I have superimposed the actual TDR image of a splice, a characteristic sine wave, in the lower-right-hand corner.

(3)       Neutral Corrosion

The physics are even simpler for neutral corrosion. The capacitance and inductance components are insignificant. A good old-fashioned resistance increase is displayed as an impedance increase. Check out the nearby image.

(4)       End-of-cable

Simpler still, the end of the cable is characterized by either an infinite impedance increase if the circuit is open or an infinite impedance decrease if the conductor is grounded to the neutral. When used, grounding devices add some more color to the wave shape, but the basic idea remains the same.

The TDR signal is reflected by each of the above impedance changes and the time the signal takes to travel to and then from the impedance change can be used to estimate the distance to that change. Note that the TDR is not a pinpointing technology, it provides a location estimate. To pinpoint splices and corrosion a second technology, radio-frequency (RF) locating, is utilized. If you desire, I will be happy to explain how that works too. NRI-12, described earlier, provides step-by-step instructions to accomplish RF pinpointing.

Your adroit amphibian,

T. B. Frog

DC Testing

Dear Ms. Frog,

We have been using DC testing for centuries without any problems. How do you explain that, oh wet and wise one?

Oregon Anomaly

Dear Anomaly-

DC testing of medium voltage AC cables comes up only occasionally.  I discussed the warranty impact in an April 14, 2010 post, titled “DC Testing to sectionalize faults – Warranty Impact.”  Click here to check out that post. There are many anomalies in Oregon that may never be explained, but it seems unlikely that the laws of physics are different in The Beaver State. I suppose there is a chance that everybody else is wrong and you are right. It happens to me all the time that I defend a position that is contrary to conventional wisdom.

I am actually not an expert on DC testing, so I have to rely on those that are.  One way I can be pretty sure that DC testing is inherently destructive is that the folks that manufacture and sell DC testing equipment croak along on the same chorus.  To wit, HV Diagnostics, Inc., one of the most respected suppliers of high voltage test equipment pronounces in its brochure:

“On Medium Voltage Extruded (XLPE, PE, EPR) cables, DC is no longer recommended by most international standards. DC has been found to be both destructive, causing premature failure of aged MV cables, and/or ineffective in detecting many types of serious pending insulation defects in new and old cable installations.”

You have to take that kind of pronouncement pretty seriously, because the supplier sells DC testing equipment.  As for your anomalous experience, I would recommend that you compile a comprehensive data set and use randomization and suitable controls.  Anecdotal results are inherently misleading. Also make sure that the equipment operator’s job does not depend upon the results – the guys that do testing for a living seem generally to be proponents of testing.

In cahoots with the beavers,

T. B. Frog

Tanδ ex post facto

Dearest Amphibian,

I have sent you some before-and-after diagnostic data (0.1Hz tan-delta) on two cables treated with Novinium® Ultrinium™ 732 fluid? The results are extraordinarily positive. What say you?

Greater Chicago

Dear Greater-

The data you provided is reproduced in the chart nearby. A few of my historical postings provide evidence that I am not a big fan of diagnostics. For example check out the postings below ...

2010-11-12 Diagnostic Testing – Should I do it?

2010-12-12 Electrical Treeing and the Principle of Parsimony

2011-05-11 Middle East Query – Diagnostic Testing Timing

2011-05-19 On-line Diagnostic Testing

Check out the before-and-after dielectric spectroscopy data presented in another post when I addressed tan delta measurements specifically at …

2010-09-10 Cable Rejuvenation Impact on Loss Factor (tan-Delta)

The data from the University of Connecticut’s Electrical Insulation Research Center (EIRC) in that post leaves no doubt that rejuvenation has an impact on tan delta measurements, but it creates considerable doubt as to the meaning of that impact. It is also true that there can be no doubt that rejuvenation with Novinium fluid technology provides a reliable post-injection life extension – over 99.6% of all treated cables are providing failure-free performance.

It is tempting, whether human or amphibian, to embrace data when it reinforces what you already know. As a disciplined scientist, I, however, am able to resist that temptation. The 17 month improvement demonstrated by the Illinois Cable 1 and Cable 2 data suffers at least two shortcomings. First, there were precisely two cables measured two times about 17 months apart. That is not a statistically significant data set. Second, without following the tan-delta over time, it is not possible to correlate the “improvement” with a reliability-metric like AC breakdown performance, which has been measured and modeled extensively. We can rectify these two issues with a more comprehensive analysis that includes more cables and more frequent periodic re-testing. Such a program is in the works with Greater and we will report on the results as the data becomes available. The testing itself carries risks for the cables to be tested. Knowledge is not free and you can’t make an omelet without breaking some eggs.

Interested, but skeptical,

T. B. Frog

Bait & Switch

Dear Triple-D (Deceptive Denizen of the Deep),

Whenever there is a competitive bid, you guys bid your Perficio™ 011 fluid against my CableCURE^®/XL fluid.  Then after you win – and you almost always do – I find out that you don’t even supply Perficio fluid.  Aren’t you guilty of baiting and switching?  Won’t you start playing fair? Don’t you feel badly offering an inferior product?

SwitX

Dear SwitX-

The only thing that is triple-D on this girl is my belly! Deceptive and Frog don’t rhyme or alliterate for a good reason.

You should write more often. I love hearing from my competitor, but a little more civil tone would be appreciated. A great number of my newest friends used to work for your firm, so I know you work with some great folks. Check the non-compete portion of your employment agreement – we are hiring! Only the best, brightest, and nicest are welcome here though.

And we are the epitome of fairness. There are no secret handshakes. Novinium fluids and processes are all unambiguously documented on our web site. Can you say the same? The “inferior” word is a bit of a low blow. The Latin word “Perficio” means perfected, and Perficio 011 fluid is the perfection of the two-decade-old technology practiced by your colleagues. The formulation is dominated (over 90%) by the same monomer that dominates (over 90%) CableCURE/XL fluid.  However, Perficio 011 fluid is not flammable and, thanks to patented catalyst technology (7,700,871), soak periods are not required to enjoy similar medium term life extension performance. Perficio 011 fluid provides a safer, faster, and better circuit owner experience than the two-decade old technology against which it is typically pitted in a bid environment.

Perficio 011 fluid is, however, “inferior” in one sense.  It is inferior to Ultrinium™ brand fluids. Ultrinium fluids enjoy all of the benefits of Perficio fluid together with a host of performance advantages too numerous to mention. To explore those other performance advantages, start with my January 3, 2011 post on “Catalytic Considerations.”

For almost all of the bids that we earn with superior Perficio 011 fluid, our circuit owner customers choose to upgrade their technology from Perficio fluid to Ultrinium fluid. They do this, because although Perficio is superior to the two-decade-old approach, Ultrinium is safer, faster, and better still! Perficio is less costly (on a first cost basis) than Ultrinium technology for two basic reasons. First the fluid itself costs less, because the monomer, which makes up over 90% of the formulation, is made in high volumes for dozens of commercial applications – high volume means lower price. Second, the relatively small size of the monomer means its viscosity is lower, and hence the time required to inject is less than with the more advanced Ultrinium fluids. Lower injection times yield lower labor cost. The incrementally higher first cost of Ultrinium technology is easily justified by circuit owners because of its longer life.

Finally, I sleep well at night, because my circuit owner friends make the rules of the game. You and I play by their rules. If a circuit owner desires a bid for the lowest price with the technologically lowest common denominator, we have an obligation to provide that option. We don’t recommend it, but we are happy to supply it.  Our view is that when it comes to rejuvenation choices, circuit owners have three … a good choice, a better choice, and a best choice:

Good – Two-decade-old technology invented by Novinium founders.

Better – The perfection of the “good” choice is not flammable and does not require a soak period.

Best – Ultrinium 73X technology, which is tailored to each individual circuit and utilizes molecules designed from scratch for cable rejuvenation.

Don’t Wait to Switch,

T. B. Frog

CableCURE is a registered trademark of UtilX Corporation.

Dearest Green One,

I have a need to rehabilitate some aging URD circuits.  How long have Novinium fluids and injection technologies been in use?  I prefer to use proven technology.

Signed,

Integrated Diagnostics 

Dear BF,

My firm will consider and evaluate additional services beyond rejuvenation that will add quality or value to a requested proposal.  Additional options for cable testing services would be of particular interest.  An explanation of services and associated costs must be included with all additional service offerings.  Information submitted for this may lead to additional evaluation points in the “services to be provided” category.

Please help me with my decision matrix,

Tahoma

Dear Tahoma-

For my readers who are not local to the Pacific Northwest, like you and I, Tahoma is a local Indian name, which means “snow peak” and designates Mt. Rainier, the snow covered volcano close to Seattle and Tacoma.  I have a view of Tahoma from my pond too – feel free to visit me anytime and I will be happy to share my grubs.  I’m all for decision matrices.  Every time one of these has been used Novinium comes out on top – safer, faster, better.

Your query suggests that you have a particular interest in cable testing services.  I have provided several posts in the past that describe the issues and challenges associated with diagnostic testing.  I list several of them below for your review:

In short, this frog is skeptical of claims of efficacy for any of the commercially available diagnostic tests.  Compare the double-digit false positives and double-digit false negatives inherent in testing with this single digit – one percent.  That’s the number of post treatment failures that have occurred in all cables proactively treated with any of the globally commercialized rejuvenation technologies.  Novinium’s post-treatment reliability record is even better than the average!

Occasionally there are cases where diagnostics are appropriate.

Novinium’s diagnostic tool box includes several kinds of instruments including infrared imaging and three kinds of on-line partial discharge detectors.  Novinium uses infrared imaging technology to identify improperly installed compression connectors.  The picture nearby shows a side-by-side image of two splices, one installed properly and the other suffering from thermal runaway.  Three different on-line partial discharge detectors are available to pinpoint discharges in terminations, splices and cables.  A high frequency current transformer can be clipped around a cable or its neutrals to detect discharges in the cable or connected equipment.  A Transient Earth Voltage (TEV) sensor allows the pinpointing of local discharges.  For applications where it is not prudent to approach a piece of operating equipment such as air operated switchgear, an airborne acoustic sensor can locate discharges inaudible to the human ear.

In addition to these instruments, Novinium provides consulting services to circuit owners to diagnose problem areas using failure data.  This approach is the lowest cost and most accurate diagnostic available.  The method was documented in a DEIS (Dielectrics and Electrical Insulation Society) Feature Article in the March/April 2009 issue of IEEE Electrical Insulation Magazine, Diagnostic Testing of Stochastic Cables.

Diagnostically yours,

Thermo B.F.