Tdworld 1518 Ohmcheck3

Ω-CHECK Concentric Neutral Resistance Tester Returns

Dec. 3, 2013
This product has been produced for almost 20 years, originally developed by Georgia Power (now part of The Southern Company) in its Georgia Power Research Center.

High Voltage, Inc. has introduced its new Ω-CHECK Concentric Neutral Resistance Tester; the Ω-Check Tester. It is designed to measure the extent of deterioration of a concentric neutral of a power cable (how many strands have opened).

A concentric neutral is made up of many strands of round or flat wire helically wrapped around the cable insulation and usually grounded at both ends. Its purpose is many. Severe problems can occur for a utility if this neutral has corroded to a point where it can no longer carry return currents and is not capable of returning fault currents from a fault location back to the grounded end of the neutral. This concentric neutral may have 6 – 20 (?) strands of aluminum or copper wire wrapped around the insulation. Whenever a strand corrodes and opens, there is an incremental and measureable change to the neutrals resistance. This is what the instrument measures: how much of the neutral remains intact.

Ω-Check Neutral Tester History

This product has been produced for almost 20 years, originally developed by Georgia Power (now part of The Southern Company) in its Georgia Power Research Center. It, like many, had a problem with corroded neutrals and worked on developing a method of testing them. This research and development center was later transferred to Georgia Tech Institute in Atlanta and became what is now NEETRAC. At that time, GP transferred the rights to the product to Utility Tools & Services of Roswell, Georgia. The product development was continued and completed and the product was marketed throughout the United States.

In 2012, UTS decided to no longer produce the product and asked HVI if it would like to take it over, an interest expressed to UTS years ago. So, the Ω-Check is now a product of High Voltage, Inc. HVI did not buy UTS nor any assets or liabilities of the company and is not responsible for existing products in the field, although the company will try to help current customers the best it can. It is simply building a similar product. UTS no longer wishes to carry a product that is not patented or trademark-protected. At this time HVI is applying for trademark status for the name Ω-Check.

UTS had sold  more than 80 units, mostly to utilities that installed thousands of feet of non-jacketed concentric neutral cable in the 70s & 80s. And surprise, the neutral wires corroded. Needing to solve unacceptable voltage fluctuations and shock problems from ungrounded feeds, as well as no longer having a proper return current path, and worse, no return path for high fault currents, many utilities turned to this product, the only product of its kind. There are still unjacketed cables in the ground but also jacketed cables are subject to corrosion when the outer sheath is punctured and water gets in. There are also other applications where the Ω-Check is needed that will be further explored and developed. A ground cable integrity test is another good application.

The Ω-Check Tester is a unique product serving a specific application. There may be other techniques used to try to perform the same tasks, like using a TDR/Radar unit to look at the neutral wires or a DC voltage output resistance meter, but none can perform the job like the Ω-Check, according to HVI.

Voice your opinion!

To join the conversation, and become an exclusive member of T&D World, create an account today!