ESMO 2016 - The Demo You May Have Missed

If you attended the ESMO show in Columbus, Ohio 2 weeks ago then you may have seen a Haverfield aerial line crew performing some fantastic demonstrations. Click the image below to see a short video of a couple of their demonstrations.

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And for those of you who stopped by the ClampStar booth, "thank you!" We appreciate your time and trust that we were able to satisfactorily answer all your questions.

As the grid ages, many electric utilities are experiencing a large increase in downed lines due to overhead connectors reaching the end of their service life. Installing ClampStars on them before they fail is the best way to prevent outages and protect the public. ClampStar provides a Life Extension solution for virtually all overhead conductors.


Here's What To Do After Finding Hot Connectors

As the grid continues to age, many utilities are increasing connector inspection frequency with a main goal of preventing outages and wire down incidents. One simple and relatively inexpensive line inspection method utilizes Infrared (IR) technology.

The above images were provided by a utility located in Pennsylvania.

Image #1 in the IR photo below shows the interface of the conductor at the entrance of the dead end body at a significantly high temperature.

Image #2 shows the same DE in the Visual Spectrum.

Image #3 shows the same DE cooled following ClampStar installation.

Image #4 shows the now corrected DE in the Visual Spectrum.

 

When helicopters are used to perform line inspections they should be equipped with appropriate ClampStar units so damaged and degraded connectors can be immediately corrected. This results in substantial cost savings compared to returning at a later date and immediately reduces the possibility of downed lines caused by failed connectors.

ClampStar....

  • Lightweight design installs in less than 10 minutes!
  • Permanent installation for deadends, inline splices, suspension clamps, OHSW and damaged conductor
  • Easily installs over existing connectors
  • No mechanical grips, Come-Alongs, jumper cables or cutters needed
  • Installs with hot sticks or barehand
  • Available for copper, composite core and all aluminum stranded conductors

ClampStar units are readily and quickly installed from any aerial platform (including helicopters, click here to see a video).

ClampStar shunts provide an excellent solution for PERMANENT mechanical and electrical upgrade to existing overhead connections. ClampStars are also used to increase the performance rating of existing splices and other connectors, clamps and fittings for the purpose of increasing line ampacity that may be presently limited by such devices.

Each unit is prefilled with proprietary CC² inhibitor to prevent galvanic corrosion and is designed with an integral fastening assembly that provides a high conductivity path and incorporates flat and Belleville washers to maintain compressive force regardless of thermal contraction and expansion.

NOTE: Safe-T-Link Tether assemblies are available for deadend and suspension clamp applications requiring additional mechanical support.

As the grid ages, many electric utilities are experiencing a large increase in downed lines due to overhead connectors reaching the end of their service life. Installing ClampStars on them before they fail is the best way to prevent outages and protect the public.

The smartest grid in the world looks pretty dumb when it is lying on the ground!


Many Utilities Ban The Use of Automatic Splices

There are estimated to be 250 million automatic splices installed on overhead power lines in North America. The majority of which were installed over 30 years ago.

A variety of reports in the field indicate the service life of automatics is as short as five years up to, and perhaps surpassing 30 years.

A recent event, where an automatic splice, installed for only 5 years, let go and dropped a line on a woman, ultimately resulting in her tragic death. The lawsuit resulted in an award of $105 Million!

Unfortunately, due to the advanced age of the power grid, overhead splice failures are increasing at a rapid rate putting the safety of the unsuspecting public at risk.

Google “Swingset Electrocution” to see a video of an overhead power line that came down on top of a metal swing set. Luckily, no children were in the area when this potential catastrophe took place.

As a result of this steadily increasing problem, many utilities have completely banned the use of automatic splices or are limiting their use only for the purpose of emergency restoration.

Many utilities are also correcting and protecting existing splices and overhead connectors by installing permanent ClampStar® shunts on them. ClampStar installs in a few minutes, is relatively inexpensive, and results in a connection of significantly higher integrity than even that of an original, properly installed connector!

CSR-0325-015 Protect with CS

ClampStar® is intended to correct and reinforce the deteriorated electrical and mechanical performance of hot-running, aged or degraded splices and other connectors.

ClampStar, along with proactive maintenance practices improves safety and prevents unplanned outages. ClampStar is the industry’s only PERMANENT solution for protecting overhead splices and connectors.

ClampStar is the least expensive insurance you can buy!


Classic Connectors USA Introduces Overhead Shield Wire (OHSW) Protection And Correction

When attending the upcoming IEEE show in Dallas, please visit the Classic Connectors booth #4736 to see the new ClampStar® for Overhead Shield Wire. This new ClampStar is designed for both tangent and deadend applications as well as splices.  Full tension on galvanized and HSS, as well as Alumoweld and OPGW!  Both insulated and non-insulated versions are available.  An option for copper is also offered. All the features you’d expect from ClampStar: prefilled with a proprietary inhibitor, torque-shear fasteners, First Class, High Integrity Solutions!

  • Lightweight design installs in less than 10 minutes!
  • Easily installs over existing connectors
  • No mechanical grips, Come-Alongs, jumper cables or cutters needed
  • Installs with a hot stick or barehand

ClampStar OHSW units are a permanent repair fitting composed of an attachment head, which connects to the OHSW and a connecting link that attaches to the tower bracket. This connecting link is available in either an insulated or non-insulated design based on the application. A custom bracket is included to anchor the assembly to the tower. This unit serves as an OSHW safety catch to prevent the shield wire from falling into the energized conductors or substation bus below.

ClampStar units are readily and quickly installed from any aerial platform (including helicopters). ClampStar units may be used for a variety of repair situations, at splices, dead-ends, suspension systems, or wherever conductor or attachment hardware damage has occurred, or may occur.

ClampStar shunts provide an excellent solution for PERMANENT mechanical and electrical upgrade to existing OSHW connections.  ClampStar will meet NERC's requirements for OHSW safety anchors without costly replacement, repair or expensive downtime.

Each unit is prefilled with proprietary CC3 inhibitor to prevent galvanic corrosion and is designed with an integral fastening assembly that provides a high conductivity path and incorporates flat and Belleville washers to maintain compressive force regardless of thermal contraction and expansion.

As the grid ages, many electric utilities are experiencing a large increase in downed lines due to overhead connectors reaching the end of their service life. Installing ClampStars on them before they fail is the best way to prevent outages and protect the public.

The smartest grid in the world looks pretty stupid when it is lying on the ground!

Other ClampStar distribution and transmission products will be on display. There will also be a hands-on demonstration. Come on by and discuss your specific application with our engineers.

We look forward to seeing you in Dallas!


Classic Connectors USA Introduces a New Transmission Class ClampStar® That Substantially Decreases Total Installation Time

This new ClampStar model CSR-1631-048 is designed to protect and thermally uprate connectors to meet n-1 contingency conditions as well as continuous service on overhead transmission lines with Aluminum and ACSR type conductors sized from 1272 Bittern to 1780 Chukar and up through 2000 kcmil Cowslip AAC

Each unit is prefilled with proprietary CC2 inhibitor to prevent galvanic corrosion and is designed with an integral fastening assembly that provides a high conductivity path and incorporates flat and Belleville washers to maintain compressive force regardless of temperature induced contraction and expansion.

ClampStar shunts provide an excellent solution for PERMANENT mechanical and electrical upgrade to existing conductor connections. And ClampStar helps meet NERC's maximum conductor operating temperature requirements without costly replacement, repair or expensive downtime. Additional sizes are available for splices, suspension clamps, deadends, and damaged conductor repair. ClampStar units are designed for use on ACSR, AAC, AAAC, ACAR, ACSS & Fiber composite core. ClampStar units are also available for use on copper conductors.

·       New lighter weight design installs in less than 10 minutes!

·       Decreases total installation time by 70 - 80%

·       Easily installs over existing connectors

·       No mechanical grips, Come-Alongs, jumper cables or cutters needed

·       Installs with a hot stick or barehand


The most cost-effective, technically superior, uprate technology alternative

In 2000, NERC began advising utilities to consider actual field conditions to confirm transmission line thermal ratings. In turn, many utilities have surveyed transmission lines to identify critical issues and determine whether their lines are capable of meeting required contingencies.

Depending on line length, utilities may have to replace dozens or even hundreds of compression dead-ends and mid-span splices. Field crews not only have to work on tight schedules, but obtaining clearances to de-energize lines may not be an option. If outages can be obtained, circumstances may require a utility to fund spinning reserve from another source to accommodate the outage if the duration of the transferred load exceeds the capacity of the alternate source. To circumvent these challenges and save a substantial amount of money and time in the field, proven technology that first became available in 2008 provides airborne power line contractors the ability to assist utilities by installing shunt technology via helicopter.

Click here to read the latest T&D World Magazine article about the most cost effective, technically superior alternative for uprating and repairing overhead transmission lines. You'll learn how to quickly restore both mechanical and electrical integrity to connectors with a single device, designed to be installed on energized lines without the need for power interruptions.

Click here to watch the Air2 aerial lineman install ClampStars.


Classic Connectors USA Introduces the Newest ClampStar®, The Latest in Connector Corrector Technology, for Use on Copper Conductor

January 15, 2015 -- Classic Connectors USA, CSR-0325L-007-P is designed to protect automatic splices on overhead, copper conductor sized from #6 - #2 AWG. In addition to torque limiting nuts, each unit is supplied with nickel-plated keepers, and is prefilled with proprietary CC² inhibitor to prevent galvanic corrosion. The unit weighs 1.75 lbs. and can be easily installed on an energized line with a hot-stick or gloves. ClampStar® helps avoid potential catastrophes and expensive lawsuits resulting from failing overhead splices. In just minutes, this eliminates risk and prevents connector failures before they occur, without costly replacement, repair, or expensive downtime. Additional sizes for use with copper are available for splices, suspension clamps, dead-ends, and damaged conductor repair. ClampStar units are also available for use on all aluminum stranded conductors, e.g., ACSR, AAC, AAAC, ACAR, ACSS & fiber composite core.


International Lineman's Rodeo Video Montage

This video pays tribute to the those highly trained and dedicated individuals that keep the lights on. They're out there in extreme conditions doing what they do best and we appreciate it!

https://www.youtube.com/watch?v=giqfz_8d4OY


Choosing the Right Fastener - Part ll

By Carl Tamm

In the first part of this article, a brief mention was made regarding “conductivity” of fasteners.  This second section will address that issue.

Peculiarities of electrical connectors give rise to further thought of fasteners.  It is not exceptionally difficult, using reasonable workmanship and materials, to make an electrical connection of reasonable conductivity initially – however, to make one which will provide exceptional duration for many decades is another story.

While there are many types of “bolted connectors” used in the utility industry, for simplicity references this article will relate to flat “pad-to-pad” type connections.  The physics involved in the atomic structure of the electrical interface are too involved to address in this article, however sufficient evidence is readily available to show that a typical 4-bolt pad-to-pad connection will achieve less than 2% of the “available” surface area that will actually make an electrical connection.  Some of the earlier references to this phenomenon of area immediately surrounding the bolt holes being the only actual contact area date back over 55 years.

Kaiser Aluminum – Electrical Bus Conductors, 1957

Accepting this long stated peculiarity to be true, one might ask, “What could be done to improve that value?”  The industry has been striving to improve the area of contact “between” the pads – but the obvious option of allowing the bolts to serve as conductive paths is often overlooked.

Use of conductive washers and fasteners can provide additional current paths from the backside of the respective pads, through the fasteners!  How obvious is that?  Why do so many disregard this simplistic improvement?  Some other misunderstandings, such as reusing fasteners, will be addressed in a future part of this article.

Perhaps a simplistic understanding of fastener conductivity will help.  One may look at either conductivity or resistivity.  I prefer the former, as the numbers are more simplistic and easy to understand.  The common basis used for conductivity values is the International Annealed Copper Standard, abbreviated IACS.  The following chart indicates values for a number of materials commonly used in our industry, and a few more for reference.

Most are surprised to learn that Gold is not the most conductive material, but is significantly superseded by Silver! The attributes of gold, and its place in Contact Physics is not the subject of this article. Of equal surprise to most, is that while we all recognize iron and steel are conductive, its value of conductivity is only 2.5% IACS. This value is close enough for argument, not to get into the specific values of different alloys, and represents all common ferrous alloys, and includes “stainless” alloys.

Alloys used for connectors commonly range from 16% to about 44%. While Silicon Bronze bolts, or the common aluminum alloys used for bolts are not nearly as conductive as the materials used for conductors, they commonly do approach the conductivity of many connectors, of approximately 16% to 24%. The lesser degree of conductivity of these fasteners is due to the alloying elements used to provide the strength needed for fasteners. Still, these conductive fasteners provide 8 to 12 times the conductivity of steel.

What is the result of using steel or stainless steel bolts in connectors? While very low in conductivity, they are yet conductive, and the low value of conductivity is the reason for the “high resistance” associated with steel. The very definition of resistance is associated with the thermal rise of the material as the result of passing electrical energy through it. The physical effect is the expansion of the material due to the thermal rise. With bolts, the higher the temperature, the less clamping force provided!

To counteract this, properly designed and applied Belleville washers are used to maintain the clamping force, as Mr. Goch covered in Part 1 of this series. As Part 2 began, our purpose is to provide a bolted joint that will maintain the electrical integrity of the connection over many decades. Maintaining the clamping force is paramount to achieving this goal. The following illustration depicts the effects of the difference in the coefficient of thermal expansion between differing materials used in electrical connections.

As the illustration depicts, differing materials expand at differing rates over a given temperature rise.  This property is given stated values for different materials, known as the coefficient of thermal expansion related to the respective materials.  Both aluminum and copper alloys expand at a greater rate than steel.  The use of steel bolts, without the benefit of properly sized and applied Belleville washers will result in rapid creep of softer material of the connectors, and the joint will loosen over time.  Of course, as it loosens, the resistance will rise, and with that given rise in resistance, the thermal rise for a given current will increase.

There exist several design features incorporated in ClampStar, the result of which provide a superior connection to other types of connections, including compression connectors.  Thus another reason ClampStar provides the properly engineered Belleville washers in its fastening system!  As Mr. Goch stated in the previous part 1, the torque nuts, designed by Classic Connectors, Inc., prevent over-tightening of the fasteners, and thereby prevent over compression of the Belleville washers.

Additional information on Belleville washers will be incorporated in another series!

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Choosing the Right Fastener

By Waymon P. Goch

With proper attention to the fastener assembly, the best choice is almost always fasteners of the same material as the components being joined. The primary reason is it eliminates differential thermal expansion and contraction, and just as important, since we are talking about electrical connectors, is that it will be conductive, at least more conductive than steel fasteners.  More discussion on this subject in a following article.

A common misconception is that stainless steel fasteners do not rust, but they do rust under certain conditions. Stainless steel remains stainless in unpolluted atmospheres and when immersed in moving or flowing fresh and seawater. In humid marine environments or stagnant moisture conditions, type 304 stainless, for example, may rust locally in pitting, crevice, stress, concentration cell, knife edge, and galvanic corrosion. The exposure environment and chemical composition of the stainless steel will dictate whether or not rusting will occur.

Stainless steel owes its corrosion resistance to a very thin, compact passive surface layer that forms upon exposure to oxygen. If the surface is scratched and exposed to oxygen, the scratches will again become passive. It is primarily this passive layer that is also responsible for galling and seizure of stainless threaded fasteners. The layer may flake with small particles becoming trapped in the thread bearing surfaces where the pressure is sufficient to cold weld the internal and external threads together. The use of anti-seize compounds and different grades of stainless are often recommended to prevent or minimize galling and seizure but these options may only be partly successful. By far, the best solution I have found over the years is to mechanically zinc plate either the stainless bolt or nut (normally the nut).

Particular attention should be given to this “galling” or seizing tendency.  The purpose of the bolt is to provide a clamping force between two or more components.  During assembly, the tensile stress which provides this clamping force is obtained by torque applied, less the friction between the threads of the bolt and nut, and the friction of the face of the bolt against the mating surface.  The most common means of determining that the appropriate tensile stress and elongation of the bolt is achieved during assembly is calculated against torque.  “Galling” or seizing of these threads consumes the force provided by the torque applied, giving a false indication of clamping force achieved.

There are many applications in which stainless steel fasteners are appropriate but they should not be considered universal.

How does a bolted joint work?

A properly tightened bolt is essentially a spring; achieved through elastic elongation of the bolt. Under constant static loading at a constant temperature, that alone would be entirely satisfactory without the need for lock washers, Belleville spring washers, or other devices to maintain clamping force. However, most applications are dynamic and require additional consideration.

The well-accepted equation for computing torque-tension relationships in bolted joints is:

T = kDW/12

Where T = torque in lb-ft, k = friction factor or torque coefficient, D = bolt diameter in inches, and W = bolt tension in lbf.

The static friction constant k varies with the fastener material and material condition (lubricated or dry) and ranges from 0.11 for lubricated steel to around 0.30 for lubricated aluminum and stainless steel. The overall torque coefficient depends upon the materials being joined, thread clearance, and the torque coefficient of the bearing surface against which the bolt head or nut is being turned. Friction is an important consideration because it represents torque that is lost in overcoming friction and not applied to create bolt tension.

Recommended fastener torques for common sizes, grades, and materials are provided by manufacturers as well as industry standards such as the Industrial Fasteners Institute, ANSI C119.4, and others. Recommended torque is usually based on final fastener tension within the elastic limit and is typically 60 – 70% of the proportional limit, yield point, or proof load. The bolt will continue to stretch if loaded beyond yield but will be unable to return to its original length, thereby reducing the clamping force.

The absence of torque wrenches in tool belts and bags of line personnel and installers frequently results in a policy of tightening “until tight” then applying another half or full turn.

ClampStar® avoids this potential problem, assures proper installation torque, and eases installation by providing torque-limiting nuts with an outer section that shears off at the proper torque, leaving a permanent hex nut in place, regardless of the type of wrench employed. This facilitates the use of pneumatic, electric, hydraulic, or battery operated nut runners, wrenches, and rattle guns.

Conventional spring or split lock washers are frequently recommended for maintaining fastener tension under dynamic loading. However, a good definition of a spring lock washer is a flat washer with a split. They are ineffective in maintaining live spring follow up because they completely flatten under relatively low compressive loading; typically around 350 lbf for ½” lock washers.

The most effective means of assuring live spring follow up is the use of Belleville type spring washers, properly sized, that will remain within its working range and not flatten or reverse, under any anticipated thermal or mechanical load excursions.

So, how do we choose the right fasteners?

The majority of electrical connectors are aluminum-to-aluminum, copper-to-copper, aluminum-to-copper, galvanized steel-to-galvanized steel and galvanized steel-to-copper or aluminum.

Proper surface preparation and the use of the correct inhibitors and joint compounds are critical steps in the creation of a low resistance electrical connection to assure long service life, but those are subjects for another time.

The preferred and recommended fastener materials for joining like and unlike metals are shown in the following chart. Although the chart references flat bar connections, the same applies to pad-to-pad as well as connections of other shapes.

Aluminum bolts are typically 2024-T4 with a #205 Alumilite finish, washers are 7075-T6 and nuts are 6061-T6 with a wax finish.

Silicon Bronze alloy bolts, washers and nuts are preferred for copper to copper connections.

Stainless steel bolts, washers and nuts are primarily type 304, 304L or 316 austenitic stainless. Type 316 has better corrosion resistance and greater creep strength than 304 or 304L due to its slightly higher nickel content.

Hot dip galvanized steel bolts are normally ASTM A307 grade 2 low carbon steel or ASTM A325 grade 5 medium carbon or low alloy steel. Grade 2 bolts do not have a grade marking on the head whereas grade 5 is marked with 3 radial lines. Both may contain the bolt manufacturer’s identification and both are galvanized according to ASTM A153. Galvanized or stainless steel flat and Belleville spring washers may be supplied and used with galvanized steel bolts. Galvanized steel nuts are tapped oversize for a class 2 fit on galvanized bolts.

We’re sure that readers will find this brief discussion worthwhile.

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