Each year, millions of people and thousands of businesses are impacted by underground cable system failures. IMCORP is dedicated to advancing the understanding of how these failures occur and more importantly, how they can be avoided.
Jan 25 2018
Monitoring Detects Failing Joint
By: Ben Lanz, John Kreso and Bill Corrente
This summary describes IMCORP’s findings during the dissection and root cause analysis of a substandard joint removed from a system feeding a critical facility. The IMCORP Factory Grade® technology targeted 7 of 51 joints that had sub... Read ArticleDec 21 2017
Water Trees Don't Fail Cable
By: Ben Lanz and Bill Corrente
Posted in: Wind, Utility, Solar, Renewable, Generation, Facility, Cable
Water Trees Don't Fail Cable Decades ago we learned from many of the leading industry experts that water trees fail cable and we believed this industry myth until we collected cable performance data using the IMCORP Factory Grade&re... Read ArticleJun 09 2017
Termination Damaged but Passed by VLF Test
By: Ben Lanz and Bill Corrente
Posted in: Workmanship, Wind, Utility, Solar, Renewable, Generation
Termination Damaged but Passed by VLF Test Our utility client asked us to commission cable systems at a new generation facility after experiencing several termination failures. The installation contractor had already tested the cable syste... Read ArticleJan 01 2017
Electrical Tree in an Aged Cable
By: IMCORP
Electrical Tree in Aged URD Cable At a client utility in the Midwest, IMCORP was performing a Factory Grade® assessment on an aged 2615 foot long solid dielectric cable. IMCORP identified the location of the defect and provided Loc... Read ArticleOct 28 2015
PD Activity Identified During Assessment of Aged Utility Cable
By: IMCORP
During the reliability assessment of aged underground residential distribution (URD) cable systems at a mid-western electric utility, one particular cable sample was found to exhibit low levels partial discharge (PD) activity. These PD sites were e... Read ArticleOct 27 2015
Low Signal Magnitude (pC) but Serious Cable Defect
By: Ben Lanz and Bill Corrente
Posted in: Workmanship, Wind, Utility, Renewable, Cable
While commissioning new generation project in the multiple defects were identified within the cable system. One particular cable exhibited defects in the dozens of low magnitude partial discharge signals at two times the operating voltage. Th... Read ArticleDec 18 2014
Wind Farm Cable with a Small but Very Serious Defect
By: IMCORP
Posted in: Workmanship, Wind, Renewable
After performing an initial Factory Grade® assessment at a renewable energy plant, a cable was found to have near end termination discharge at operating voltage. The on-site crew attempted to mitigate the Partial Discharge (PD) activity by disa... Read ArticleNov 18 2014
Oil Damaging to Cable Semicon
By: IMCORP
While performing a Factory Grade® assessment on a cable at a utility client in the southern part of the US, substandard partial discharge (PD) was observed near a termination. Upon visual inspection it was noted that the cable’s ou... Read ArticleNov 18 2014
Manufacturer’s Defect: Conductor Shield Protrusion
By: IMCORP
During the Factory Grade® commissioning of a new cable system at a critical generation facility, substandard partial discharge (PD) activity (per ICEA S94-649) was observed at numerous points in a few cable systems. The client... Read ArticleFeb 05 2014
Severe Termination Damage at a Utility
By: IMCORP
An IMCORP Field Engineer was performing a Factory Grade® asessement for a utility client. The assessment results showed partial discharge (PD) at operating voltage in the far end open air termination. Upon investigation of the far end ... Read ArticleFeb 05 2014
Multiple Defects Found at a Wind Farm
By: IMCORP
Just a few weeks ago, IMCORP was performing its Factory Grade® assessment at a wind site in Canada. The assessment indicated substandard partial discharge (PD) at the near end termination. To determine the source of the PD, the assist ... Read ArticleSep 23 2013
Residual Semicon Under a Cable Termination
By: IMCORP
IEEE 386 Non-Compliant While performing a Factory Grade® assessment for a utility client, IMCORP detected sub-standard partial discharge (PD) activity in URD cable elbow termination. After the assist crew cleaned and applied dielectric ... Read ArticleSep 20 2013
Invisible Semicon Damage Near at Termination
By: IMCORP
IEEE 386 Non-Compliant While performing a Factory Grade® assessment, IMCORP found partial discharge(PD) activity near a separable connector (T-body) termination. Visual inspection of the termination showed no indication of a problem. Th... Read ArticleMay 13 2013
Issues with Termination at a Utility
By: IMCORP
IEEE 386 Non-Compliant Earlier this year, IMCORP was performing its Factory Grade® assessment for a utility client and detected PD at 1.3 times operating voltage at the far end termination (not meeting IEEE 386 requirements). The... Read ArticleMar 19 2013
Delaminated Ambers in Cable Insulation
By: IMCORP
Cable not meeting ICEA S-94-649 standard IMCORP was conducting a Factory Grade® assessment on a cable system when this pair of defects was pinpointed. The defects were located less than 45 meters (150 feet) apart and appeared ... Read ArticleSep 27 2012
Severe Cable Defect at a Wind Farm
By: IMCORP
Cable not meeting ICEA S-94-649 standard IMCORP was again contracted to commission a wind farm collector system using Factory Grade® technology. During the course of assessment, the IMCORP Field Supervisor came across an e... Read ArticleAug 15 2012
Improper Installation of Stress Control
By: IMCORP
A newly installed critical cable system experiencing multiple cable and accessory failures shortly after commissioning. The sites' underground cable system had initially been tested using a very low frequency (VLF) method, but after multipl... Read ArticleAug 08 2012
Termination Failure at a Wind Farm
By: IMCORP
This client used Factory Grade® technology to commission a shielded power cable system, linking a substation with a generation plant. We found twelve cable terminations on the substation end of the circuits performing well below t... Read ArticleJul 30 2012
Improper Semicon Cutback On A Cold Shrink Termination
By: IMCORP
The above image, taken at a nuclear power plant, shows a jagged semicon cutback on an open-air cold shrink termination. The cable owner first used Tangent Delta (TD) and Very Low Frequency (VLF) tests believing these were sufficient to assure r... Read ArticleJul 30 2012
Stone in Cable 176m (578ft) from Termination
By: Ben Lanz and Bill Corrente
Posted in: Backfill, Cable, Facility, Generation, Renewable, Solar, Utility, Wind, Workmanship
IMCORP’s Factory Grade® assessment discovered a substandard location while commissioning the cable systems at a generation facility. The client used IMCORP’s Location Matching service to pinpoint the defect location. N... Read ArticleJul 23 2012
PD Activity in a Y Joint at a Nuclear Facility
By: IMCORP
Posted in: Workmanship, Generation
IMCORP conducted its Factory Grade® assessment on a critical loop at a government nuclear facility in southeast USA. This particular PD occurred at a Y-joint located 185 ft. and had an inception voltage of Uo. PD a... Read ArticleApr 16 2012
Non Radial Cutback on a Cold Shrink Joint at a Wind Farm
By: IMCORP
Posted in: Workmanship, Wind, Generation
This cold shrink joint was a part of a feeder cable system at a wind farm site that failed to pass IEEE 404 specifications. Even after the Factory Grade® assessment found this joint to be substandard, the cable system's contracto... Read ArticleApr 16 2012
Non Radial Power Cable Cutback at a Power Plant
By: IMCORP
This is the open-air termination of a solid dielectric cable featuring ethylene propylene rubber insulation (the salmon colored section). Initially, this cable was deemed to be in good working order after passing a one-hour, 3Uo VLF withstand tes... Read ArticleApr 16 2012
Misplaced Stress Relief Material at a Utility
By: IMCORP
Posted in: Workmanship, Utility
This particular open-air termination transitions an underground line to a riser. Although visual inspection indicated that the cable was properly installed (it is difficult to see the mastic placement with the termination installed), the cable ... Read ArticleMar 27 2012
Semicon Defect During Installation
By: IMCORP
Posted in: Workmanship, Wind, Generation, Cable
The cable displayed here was compromised as a result of a semicon cutback error that was not recognized as a defect by the installer. When the cutback was made, the installer created a slight spiral instead of a radial cut leaving a thin slice of... Read ArticleMar 23 2012
Issues Performing Cutback on Out of Round Power Cable at a Wind Farm
By: IMCORP
Posted in: Workmanship, Wind, Generation
Featured here are medium voltage feeder cables at a wind farm substation in South Dakota. These cables are the site’s most critical link, handling the output of 10 to 20 turbines. IMCORP Factory Grade® technology found that ... Read ArticleMar 23 2012
Improper Heat Shrink Application
By: IMCORP
Posted in: Workmanship, Wind, Generation
These images show the development of a medium voltage cable failure in an open-air heat shrink termination. The first image (left) shows the IEEE 48 non-compliant heat shrink at the termination that was located by the IMCORP's Factory ... Read ArticleMar 23 2012
Power Cable Degassing
By: IMCORP
Posted in: Workmanship, Wind, Generation
These images show cross-sections of a medium voltage power cable that was installed at a wind farm in Wyoming. In this case, the IMCORP Factory Grade® technology indicated partial discharge activity on a section of cable. The PD l... Read ArticleMar 23 2012
Cable Manufacturer Defect During Repair
By: IMCORP
Posted in: Workmanship, Wind
IMCORP's Factory Grade® assessment indicated a PD site in an underground medium voltage power cable. Initial inspection of the PD site did not show any evidence of an issue. According to the latest study no visual evidence is reported ... Read ArticleMar 23 2012
Whittled Cutback on Power Cable at a Co-op Utility
By: IMCORP
Posted in: Workmanship, Wind
This image shows a 7.2 kV (medium voltage) power cable system at a co-op utility in rural Missouri that supplies power to a residential area. IMCORP's Factory Grade® assessment indicated PD activity at the separable connector... Read ArticleMar 23 2012
Power Cable Termination Cutback Issues at a Data Center
By: IMCORP
Posted in: Workmanship, Facility
Pictured here are live front terminations of a medium voltage power cable system at a critical data center in Portland, OR. After termination failures began to occur, DC HiPot testing had been utilized but came back inconclusive. At this po... Read ArticleMar 23 2012
Power Cable Damage From Backfill
By: IMCORP
Posted in: Wind, Generation, Cable, Backfill
These images show a PD site in a medium voltage power cable, part of a collector system designed and installed at a wind farm in Idaho during 2005. In the first few years of operation, the site experienced a very high collector syst... Read ArticleMar 23 2012
Power Cable Termination Cutback Issues
By: IMCORP
Posted in: Wind, Generation
These pictures show two different live front substation terminal ends at a wind farm in Canada. The client believed that the medium voltage power cable termination ends at the substation were in fine working order. Also, external visual inspect... Read ArticleMar 23 2012
Power Cable Insulation Damage (Sabotage) at a Wind Farm
By: IMCORP
Posted in: Workmanship, Generation, Cable
The discovery of this medium voltage power cable defect at a site in Canada provided an opportunity to demonstrate the effectiveness of IMCORP’s cable diagnostics. On a cable of over 1400 feet, IMCORP was able to locate the defect within si... Read Article