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Failure Causes I

January 24, 2012

Failure Causes I


I wonder if you have any information I could use to help address a concern I have heard in my company. That concern is that a 30 to 40 year old cable may have accumulated degradation due to many types of aging factors. Cable injection may not substantially address these factors and injection may not provide a very great increase of life extension for a very old cable.


Thank you for the inquiry. That is actually a great inquiry, because it will take me more than a single post to answer! The first question we have to address is: Which of the two categories of failures plague your solid dielectric circuits? In the figure nearby I ponder this question, because only you can know? At Jicable 2007, the International Conference on Insulated Power Cables, Nigel Hampton of NEETRAC (National Electric Energy Testing Research and Applications Center) provided some survey data from their circuit owner members in a paper titled, “Validating cable diagnostic tests.” Perceived failure experience of NEETRAC member companies suggested that on average, 55% of the failures in the population are cable failures, 39% are accessory failures, and 6% are unknown. The perception of Utility 21 is that almost all of its failures are cable failures and very few of its failures are accessories. The perception of Utility 4 is reversed. Utility 4 perceives that about 4 out of 5 of its failures are component failures and 20% or less are cable failures.

If the primary cause of your failures are components, consider which components are failing—terminations or splices or both. There are two injection paradigms, namely Unsustained Pressure Rejuvenation (UPR) and Sustained Pressure Rejuvenation (SPR). See “How to Inject” for more on UPR and SPR. Novinium is the only firm in the world that can use both paradigms. UPR attempts to flow through existing splices, so it is not the best choice if your firm experiences splice reliability issues. SPR replaces 100% of the splices and terminations with modern state-of-the-art components. UPR replaced all of the dead-front terminations, so if those are problematic components for you, UPR will address that issue. Novinium has made several improvements to the safety and reliability of dead-front terminations used for injection. I will describe those improvements another day.

In summary, if your reliability issues are primarily component issues, rejuvenation directly addressed these with systematic component replacement. Depending upon your specific circumstances, the Novinium masters of reliability will help you decide which injection paradigm best addresses your reliability issues at the lowest capital cost.

If your reliability issues are cable-centric, check out my next post in this series, Failure Causes II, where we will ask the question: What are the primary causes of cable failure and how is each addressed or not addressed by rejuvenation?