Transcript Slide 0
Cable Rehabilitation Program
(Second Responder Cable Treatment Program)
By Lee Maurer
Maintenance Planning
SWEDE Conference
April 26, 2011 - Bastrop, Tx
Oncor System Overview
27,000 Square Miles of Territory
630 miles
3.2 Million Electric Service Points
3,000 Circuits
Miles of Underground Primary
(Networks not included)
390 miles
17,218 Cable Miles – URD
4,641 Cable Miles – Feeder
21,859 Total Miles.
Miles of Overhead Primary
10,608 Mainline Primary
13,026 3ø Non-Mainline
5,006 2ø Lines
27,212 Single Phase Lines
55,852 Total Miles
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Cable Components
Pre-1990
Tinned Copper Insulation
Concentric Neutral Shield
XLPE or
HMWPE
Insulation
Since 1990
TRXLPE
Insulation
Aluminum
Conductor
Conventional
Conductor Shield
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Jacket
Bare Copper
Concentric
Neutral
Insulation
Shield
Aluminum
Conductor
(Strand-filled)
Super Smooth
Conductor Shield
2
Primary Underground Cable
(Network Excluded)
Previous specification cable
Current specification cable
3
Primary Cable Faults
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Cable Rehabilitation Program - Background
System wide maintenance plan (Second Responder) for extending the life of
aging infrastructure
Pre-1993 PE cable issues
8,000 cable miles – Pre-1993 PE cable
– 7,000 cable miles – URD
– 1,000 cable miles – Feeder
Cable Manufacture 1980 - 1995
– General Cable, Hendrix, Pirelli (Now Prysmian), Southwire
Capital Rehabilitation method for aged cable
– 235 cable miles rehabilitated (By Utilx)
Cost effective alternative to replacement of cable
Additional 600 cable miles rehabilitated in other programs
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Second Responder Process
When a cable faults, the troubleman (first responder) determines if the
cable is loop fed and if the faulted cable can be switched out.
Padmount Transformer
Pole Riser
Normal Open Point
Fault
Isolated Faulted Cable
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Second Responder Process (cont’d)
If the cable can be switched and service restored to the customers, the location
of the faulted cable is sent to Oncor Program Services.
Program Services will then schedule a Utilx cable repair/rehabilitation crew to
the cable.
The crew will attempt to repair and inject the cable with rehabilitation fluid.
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2nd Responder Process
4,291 sections of failed cables came through the process
since 2008
– 65% were able to be injected successfully.
235 cable miles have been rehabilitated using 2nd
responder process since 2008.
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Business Comparison
Cable Repair - Splicing
$X
– O&M Cost
– Same old cable
Rehabilitation of Span
$ 4X
– Capitalized Cost
– Added 20+ years of life
New Cable (Bore)
$ 15X
– Capitalized Cost
– New 40+ year asset
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Business Considerations that Prevent Rehabilitation
Cable installed in conduit (except preventative)
Corroded concentric neutral of 25% or less remaining
The faulted cable section must not have been deenergized more than six months.
There cannot be more that one joint per 100 feet of
cable. (Business Case)
Other Technical Reasons
– Butyl rubber cable
– Cable with tape conductor shield
– Loss of insulation shield conductivity
– Insulation shield with no adhesion
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Questions
Oncor Contacts
Lee Maurer
Senior Manager
Mark Darilek
Project Manager
Mike Sulak
Program Manager
Richie Harp
Consulting Engineer
Maintenance Planning
Maintenance Planning
Operations/Program Services
Distribution Standards
817-215-6128
[email protected]
817-215-6809
[email protected]
817-215-6151
[email protected]
817-215-6008
[email protected]
Fort Worth, TX
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