Defect Specific Cable Diagnostics Empowers Asset Managers

Posted on June 28, 2007
Posted By: Bruce Broussard
Utilities, industrial plants, casinos, commercial and government campuses, and municipal water treatment facilities all have an abundance of underground shielded power cable system assets. Many of these assets are currently being operated beyond their anticipated life expectancy. While these assets have been relatively dependable over the past few decades their incidents of failure are beginning to increase. In fact, the rate of failure will continue to increase if no actions are taken as these cable assets continue to age. This increase in failure rate is intolerable to most as it may impact rate penalties, valuable production uptime, worker productivity or important public image.

The reason the reliability of these cable systems is becoming a focused concern is due to the nature of the cable system failure profile over time. As shown in Figure 1, the expected failure of underground shielded power cable is likely to occur during the first five years due to either product defects or quality of installation. On the other hand, once the initial defects fail the system is likely to experience very few failures until the cable has been installed for at least 20 years. Around the 20-year point the age of the cable will begin to develop discreet defects at an increasing rate. The corresponding cable system failure curve vs. time is therefore shaped like a bathtub (Figure 1).

In most cases, the necessity to manage these assets proactively has been an omission in part due to the “out of sight, out of mind” nature of the asset. This is a concerning thought since many of the key assets being managed today are dependent on the connected cable to obtain the necessary electrical power to operate. The most sophisticated asset management process available will not perform effectively if key assets like power cable systems are omitted. There are two additional reasons why these critical assets have not been given the proper attention they deserve. The first reason is because of the “bathtub” curve in Figure 1. These assets, in most cases, have been very dependable through their years of operation. The second reason and subject of this article is that until now there has not been an available non-destructive means to effectively determine the actual condition of these cable systems.

Common Practices

The advancement of non-destructive power cable system diagnostic techniques, specifically, partial discharge defect specific diagnostics (DSD), empower asset managers and engineers to more effectively manage these key assets just as they are reaching a critical point in their life cycle. To date, there have been three options available:

1. Do nothing and react to failures as they occur.
2. Force failures by applying a destructive DC or AC withstand test.
3. Replace underground cable assets based on historical information (age).

Running the cable system to failure may be an acceptable approach while the cables are within the age range that places them at the bottom of the “bathtub” curve. However, as the assets age beyond that stage and outages began to occur more frequently this reactionary method of dealing with the asset becomes problematic on several fronts. Loss revenue, lower productivity, negative publicity and potential penalties in the utility segment are all potential negative results of this approach.

A common proactive approach has been to periodically apply a significant electrical stress to determine if the cable is capable of ‘withstanding” the event. The logic of this approach is to accelerate the growth of the worst potential defect to the point of failure under a controlled environment. Therefore, the failure happens during a scheduled outage vs. an unplanned event. This may not cause serious problems during the period when the age of the cable places it at the bottom of the “bathtub” curve and the number of cable defects is minimal. However, as the age of the cable increases and the cable system defects grow, this stressful “withstand” approach may begin to exasperate the development of multiple defects as depicted in the actual before and after results illustrated in Figure 2.

The other current practice has been to change out entire populations of aged cable with the belief if one 30-year-old cable is bad, then they must all be bad. This is a very expensive solution since evidence obtained utilizing non-destructive power frequency DSD indicates that this is entirely unnecessary. Data collected by applying the available DSD technique indicates that up to 85 percent of these aged cables are in excellent condition. Therefore the practice of blindly replacing cable based on age alone may end up costing three- to four-times more than necessary when you replace aged cable with 10-plus years of economic life remaining.

Best Practice

Partial discharge DSD enables asset managers and engineers to establish a solid baseline understanding of their valued cable system assets. This is encouraged at the time of commissioning of new installations in order to effectively enforce the installer warranty period or at the earliest possible opportunity to gain the necessary understanding of the current state of this important asset. Upon gaining the knowledge from performing this baseline condition assessment one is empowered to establish the necessary future asset plans.

This new DSD capability also provides a means of implementing a robust predictive diagnostic regimen to assure the future performance of your aging cable assets. This powerful asset management application empowers those responsible to proactively manage reliability at a significantly lower cost than arbitrarily replacing cable. The defect specific diagnostic approach provides actual defect location and severity information, so the option to perform inexpensive repairs vs. costly replacement can be considered. Remember, up to 85 percent of these cables are still in good operating condition and may not require any action to enhance their reliability. Therefore, the investment in having your cable assets diagnosed will actually provide you with the information to both improve your reliability and save a tremendous amount of money.


  • Power cable systems are a key asset that may not be getting the attention required in relationship to their importance.

  • As this asset ages it will require the special attention of asset managers and engineers responsible for these assets to avoid undesired results.

  • Current practices may no longer be technically or financial adequate to address the growing problem of aging underground shielded power cable.

  • New partial discharge DSD provides a powerful asset management tool to commission new cable assets, establish a baseline for existing assets, and to manage future system reliability and asset management financial goals.

Authored By:
Bruce Broussard is the Vice President of Operations for IMCORP, the world leader in non-destructive cable diagnostics located in Storrs, Connecticut. Prior to joining IMCORP Bruce spend 24 years with Eaton Corporation’s Cutler-Hammer/Westinghouse Electrical Group in various sales and marketing leadership positions. Bruce obtained his Bachelor of Electrical Engineering degree from Louisiana State University in 1982. He is a graduate of the Syracuse Graduate School of Sales and Marketing Management

Related Posts


Add your comments:

Please log in to leave a comment!
back to top

Receive Energy Central eNews & Updates


A State of the Utilities Industry Study - What Keeps You Awake at Night?

Thursday Sep 4, 2014 - 12:00 PM Eastern - Virtual Event

Faced with everything from unpredictable weather to changing renewable energy portfolios to volatile fuel prices, utilities can only be certain about one thing: uncertainty. Energy Central's Sierra Energy Group surveyed 70 utilities professionals in IT, finance, trading and risk management more...

Valuing the Costs and Benefits of Solar

Tuesday Sep 9, 2014 - 12:00 PM Eastern - Virtual Event

Distributed solar photovoltaic (PV) continues to grow in the United States. While solar PV is predominately installed in California, the Northeast, Mid-Atlantic, Colorado, Arizona and Hawaii, how to value its contribution and costs is being discussed in legislative and regulatory more...

Revenue Assurance; a boring topic unless it's your revenue

Wednesday Sep 17, 2014 - 12:00 PM Eastern - Virtual Event

Did you get a paycheck recently? Did you look over your paycheck to make sure you got paid for the work you provided? Would you be concerned if your paycheck was 10, 15, or 20% less than you expected? That's more...

Data-to-Value Realized: AMI/OMS Integration

Thursday Sep 18, 2014 - 12:00 PM Eastern - Virtual Event

The explosion of data in utilities has at times seemed to have created more problems that it has solved. One refrain from utility executives is often around the quest for more value creation from their investments in smart grid, smart more...

Utility Analytics, Challenges & Solutions Webcast Series - Session One

Monday Sep 22, 2014 - 12:00 PM Eastern - Virtual Event

The utility analytics marketplace is evolving so fast that it is hard to keep up with new technologies and processes that are transforming how utilities accomplish their mission. This webcast series provides attendees with an opportunity to see and hear more...

2014 Mobile Utility Week

Monday Sep 15, 2014 - Tuesday Sep 16, 2014 - Phoenix, AZ

This is a must-attend event for utilities professionals who are responsible for creating and implementing their organization's mobile strategy. Walk away with the knowledge and resources required to implement effective mobile solutions within the areas of customer engagement mobility and more...

CounterIntel Conference and Training - Park City, Utah

Tuesday Sep 16, 2014 - Thursday Sep 18, 2014 - Park City, UT - USA

Critical Intelligence will host our first CounterIntel Conference and Training in Park City, Utah, September 16-18, 2014. Join industry peers, industrial control system owners/operators and intelligence experts to discuss situational awareness and intelligence. Learn how leading organizations are incorporating intelligence more...

26th Annual Independent Energy Human Resources Association (IEHRA) Conference

Wednesday Sep 24, 2014 - Friday Sep 26, 2014 - San Diego, California - United States


8th Rocky Mountain Utility Efficiency Exchange

Wednesday Sep 24, 2014 - Friday Sep 26, 2014 - Aspen, Colorado - USA

Rocky Mountain Utility Efficiency Exchange (formerly Colorado Utility Efficiency Exchange) facilitates a networking and professional development conference for staff representatives of energy and water utilities serving Colorado and neighboring states who are responsible for developing and implementing customer programs related more...


Get your event listing in front of more than 100,000 industry professionals by posting on EnergyCentral's Event Center.

Sponsored Content