A new Idea For: Grid Resilience, Wildfire Mitigation & Asset Management

The weakest link in any overhead system will always be connection points, such as; deadends, suspension clamps, and splices. Conductors and well-maintained towers will always outlast connectors.

Even though some connectors fail due to mechanical stress, electrical failures appear to be more commonly reported. In these situations, the connector resistance increases over time to a high enough value that a rapid deterioration of the connector occurs, resulting in catastrophic failure due to electric overheating if no intervention is made.

The cause of an increase in electrical resistance is usually a combination of several factors:

* High initial resistance due to improper assembly/Installation or defective materials
* Degradation of electrical interfaces in the connectors through thermal cycling
* Oxidation of electrical interfaces due to contaminants and environmental effects



Fortunately, there are some cost-effective, preventive maintenance options that can reduce overall maintenance costs and even defer maintenance or replacement while at the same time, extend the life of overhead lines. Some of these options have only been available for the last decade or so and therefore it’s possible that asset managers and other decision-makers may not be aware of them.

I’m referring to Electrical/Mechanical Shunts [EMS] under the trade name, ClampStar® for use on overhead connectors and damaged conductor. First introduced in 2008, with hundreds of thousands now installed, these devices extend line life while improving public safety.
In fact, after a few recent years of destructive wildfires that devastated California, over 50,000 of these types of shunts under the tradename ClampStar® were installed in that state as a way to harden the grid for wildfire mitigation purposes.

Some experts argue that utilities could eliminate a large portion of the overhead connector inspection process and, at the same time, at lower cost, provide a life extension solution and increase public safety just by installing ClampStars on all overhead connectors. This provides the added benefit of qualifying as a capital expense project.

Since connectors are the weakest link in the system, it only makes sense to protect them. Correcting automatic splices or any overhead connectors with ClampStar is faster, much less expensive, and results in a connection of significantly higher integrity than even that of an original, properly installed connector! The installation can be performed without a power interruption, and the result is a thermally uprated connection and a visible indication that steps have been taken to protect the general public against the possibility of yet another power line on the ground that occurred as the result of a failed connector.
Because of the positive engagement of the ClampStar with the conductor, there is no “wiggle room” as with other repair-type devices. Helical type devices, commonly called patch rods loosely engage conductor strands and allow them to slip slightly under varying degrees of tension. This allows a creep factor over time with such devices, allowing tension to vary on the original connector, and can result in it working out of the original connector. The positive engagement of the ClampStar does not allow for this, operating exactly like a bolted dead-end, such as an in-line shoe type dead-end or quadrant clamp.

Proactive maintenance practices along with the installation of engineered ClampStar shunts improves safety and prevents unplanned outages. ClampStars are the industry’s only PERMANENT life extension solution for virtually all overhead conductors. Increasing power flows on some of the oldest lower-voltage circuits, especially during emergencies has put significant pressure on a power grid that was built mainly to serve local markets. ClampStars are necessary to help bring the power grid up to a level of acceptable physical soundness and reliability. With ClampStar, splices, deadends, and suspension clamps are permanently repaired with no power interruption; connector replacement is no longer necessary. They easily install in a few minutes over the existing connector. No mechanical grips, come-alongs, jumper cables, or cutters are needed. There’s no need to cut power or lines and they easily install over the existing splice or connector. ClampStar provides a substantially higher integrity connection by several orders of magnitude than any other option, allowing a line to operate at increased ampacity without the limitation of the connectors, allowing for system uprates, and are significantly faster, more economical, and safer than traditional splice replacements.
When selecting the correct EMS for your application it’s important to choose only those units that meet ANSI C119.4 class AA, extra heavy duty for restoring both electrical and mechanical integrity on weathered conductors.

If your application requirements are for High Temperature-Low Sag (HTLS) conductors, like ACSS, commonly operating at temperatures far beyond the limits of ANSI C119.4 class “AA” then you may want to give us a call. Our Technical Staff will gladly answer any questions, and share their expertise with you. HTLS is not a concern for ClampStar – all ClampStar designs are tested at 390°C (734°F) conductor temperature. This is a significantly higher temperature than listed by any electrical test standards on the planet, but is our standard, minimum performance application requirement for conductors which may be operated at 250°C continuous.

ClampStar® is an engineered, electrical mechanical shunt that significantly reduces whole-span wire replacement cost when installed over a failed connector or on a damaged portion of conductor to function as a permanent bypass electrical connection while maintaining tension in the conductor. ClampStar eliminates replacement of overhead splices, deadends, and suspension clamps and repairs damaged bare conductors through an easy, quick, and permanent fix. ClampStar is 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 presently be limited by such devices.

Please contact us for more information. 800-269-1462