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Integrated Diagnostics

June 1, 2011

Integrated Diagnostics

Q:

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!

A:

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:

Post Date Post Title
2011-05-19 On-line Diagnostic Testing
2011-05-11 Middle East Query – Diagnostic Testing Timing
2010-12-12 Electrical Treeing and the Principle of Parsimony

In short, I’m 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.

 

The splice on the left was swaged the Novinium way. Compared to the one on the right, which was crimped in the conventional way, the Novinium swaged splice runs considerably cooler.


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