Rejuvenating electrical feeder cables to secure critical airport infrastructure

–by Steve Hightower, Novinium

Dayton Power and Light is a utility company serving 515,000 customers throughout Ohio’s Miami Valley. One of Dayton Power and Light’s most critical customers is the Dayton International Airport, which the Department of Homeland Security classifies as a vital asset to the nation’s security under the Critical Infrastructure Protection Program. Dayton Power and Light is responsible for ensuring the reliability of the airport’s electrical supply and eliminating any potential electrical cable failures. However, after one of the main feeder cables supplying power to the airport terminal had experienced problem events earlier in the year, so Dayton Power and Light needed a solution to ensure reliable power for this critical customer.

Dayton International Airport:
Perhaps no other single spot on the globe has seen more aviation firsts than Dayton, Ohio. It all began when two brothers from Dayton, Orville and Wilbur Wright, began their search for the secrets of powered flight in 1896. On December 17, 1903, the Wright brothers successfully launched the world’s first man-carrying flying machine. On December 17, 1936, thirty-three years to the day after the Wright brothers’ first flight, a dedication ceremony was held to officially open the airfield as the “Dayton Municipal Airport.” The Dayton Municipal Airport featured three 3,600′ concrete runways and connecting taxiways. Soon after its opening, Trans Continental and Western Airways, later to be called TWA, began service with three daily flights.
Today, the Dayton International Airport spans over 4,500 acres, and encompasses approximately 4.7 of miles of runway. The Dayton International Airport is served by nine airlines and has nineteen non-stop destinations. There are approximately 70 daily arriving and departing flights from 17 active airline gates. In 2007, the Airport experienced passenger growth in excess of 8% for a total of 2,833,103 passengers served. According to State of Ohio data, the Dayton International Airport has a $1 Billion economic impact on the regional economy.

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Challenges:
After careful examination of the electrical power cable supplying the airport, it was determined that more than 40,000 feet of cable of this historic airport needed to be rejuvenated. Because of the problems that had previously been experienced by the airport, it was critical that the cable be rejunvated quickly. Ultimately it was determined the project needed to be completed in less than 2 months, leaving little time for planning and rejuvenation. In addition to the short time line, the cable that needed to be treated was both buried cable as well as cable in a manhole and conduit system providing the an additional space challenge. Not to mention that because this was occurring at an airport, there was additional security that required all on-site personnel working on the project to be escorted on and off the premises by airport security.

Dayton Power and Light chose to rejuvenate both the 1000 MCM and 500 MCM feeder cables supplying the airport. Dayton Power and Light had previously completed a feeder cable rejuvenation project several years ago. Electrical cable rejuvenation is an alternative to cable replacement that restored feeder cable to its full dielectric strength for a fraction of the cost of cable replacement with minimal operational disruption. In this case, Dayton Power and Light chose Novinium for to execute the cable rejuvenations because of its efficient and experienced craft team, ability to complete the project in a timely manner, 40-year warranty, and proven post-injection reliability comparable to that of replaced cable.

The process of cable rejuvenation:
Electric cable rejuvenation is the injection of a silicone fluid into the strands of aging medium-voltage power cables. The fluid migrates into the conductor shield and insulation, modifying the insulation’s chemistry and extending cable life. The electric cables returns to their full dielectric strength within as little as seven days from the date of the procedure. In this case, Dayton Power and Light chose to inject the CableCure 732/733® fluid, using Novinium’s Sustained Pressure Rejuvenation (SPR) process to treat 42,255 feet of cable. Dayton Power and Light chose this option specifically because it restored their cable to full dielectric strength within seven days in addition to the fact that the process comes with a 40-year warranty.

The process of cable rejuvenation begins with isolating, testing and grounding the cable. The use of a TDR device is employed to check every segment for splices, neutral corrosion, and length. Splices are pinpointed by using a RF locator and a measuring wheel. Once this process is complete, the process requires the digging of a pit to expose and remove the old splice. Then a radial press is used to install new injection adaptors and a splice connector. The craftwork is verified with a template for each termination and the injection tools are positioned accordingly. Initially the process will begin by injecting each sub-segment at a moderate pressure. For example, a 300-foot segment (100 meters) typically takes 30 minutes or less to inject. Once the actual injection is complete, the equipment is removed and the process is completed by installing standard elbows at each end. The final step is the re-energizing of the cable, restoring of the work pit, and moving on to the next segment of cable to be injected. This process takes a single visit with an average of 4 hours.

Solution:
In order to deal with the challenges of this project, Novninium prepared construction needs in advance, forecasting the work schedule and contingency plans and ordering supplying from around the country to arrive on-site very quickly. The crews executing the craftwork of the rejuvenation were critical to the plan. Ultimately there were five crew members that worked 6-7 hour shifts inside the airport property while two additional crews worked outside the airport.

Results:
The prior planning was successful as the project was completely in approximately three-weeks—well under the required time line. “I was very pleased with Novinium’s dedication to the project. They were able to mobilize several crews out here to make sure it got done,” said Jeff Dahlinghaus, Operations Manager, Dayton Power and Light. In the end, there was 42,255 feet of electrical cable rejuvenated at the Dayton International Airport. Careful analysis of the costs showed that the cable rejuvenation process saved over $530,000.00 over the estimated cost over the alternative of cable replacement. The key to this project was reliability. The Dayton International Airport is a part of the government’s critical infrastructure and Dayton Power and Light determined that proven results of electrical cable rejuvenation met their criteria for reliability. Today’s rejuvenation technology is comparable to the reliability of cable rejuvenation at one-third the cost of replacement. However replacement wasn’t a viable option, as it would have taken too long to replace the electrical cable that needed to be restored on this particular project. The rejuvenated cable has been restored to as-new condition and is covered by a 40-year warranty.

For more information about the project can be seen on the video case study online here.

Novinium, www.novinium.com
Dayton Power & Light: www.dpandl.com