EPRI PILC Cable Condition Assessment Project Summary

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EPRI PILC Cable Condition Assessment Project
Summary
To ICC Educational Program

• 30 April 2003

EPRI Project Manager Rob Keefe
Presented by Vern Buchholz Powertech Labs
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Project Objectives

• Examine five field, diagnostic techniques for
  PILC cable insulation.
• Compare the results of the field techniques to
  lab measurements
• Evaluate five diagnostic methods for lead sheath.

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Project Tasks

• Collect lengths of PILC cable
• Field Testing
• Insulation diagnostics on terminated cables
• Lead sheath diagnostic tests
• Tests in Substation on 2.5 km long cable.
• Lab Testing
• Conduct chemical lab tests on insulation samples
• Conduct AC Breakdown tests
• Conduct water ingress test
• Conduct accelerated aging test on lead.

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Cables Tested
Cable Type Age Utility
D 12 kV, 1-Ph, U/J 1938 Reliant Energy
E 5 kV, 3-Ph, U/J gt40 yrs Northern States Pwr
F 14 kV, 3-Ph, U/J 1961 San Antonio Pub Srv
G 5 kV, 3-Ph, Jacket 1956 BC Hydro
H 5 kV, 3-Ph, U/J 1955 BC Hydro
I 15 kV, 3-Ph, Jacket 1986 BC Hydro
J 15 kV, 3-Ph, U/J 1959 BC Hydro
K 12 kV, 1-Ph, Cambric Tapped ? Reliant Energy
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Cables Tested (cont)
Cable Type Age Utility
L 12 kV, 1-Ph, U/J 1956 Reliant Energy
M 12 kV, 1-Ph, U/J 1952 Reliant Energy
N 15 kV, 3-Ph, Jacket 1993 BC Hydro
O 13.8 kV, 1-Ph, U/J 1931 Toronto Hydro
P 15 kV, 3-Ph, Jacket 1973 BC Hydro
Q 15 kV, 3-Ph, Jacket 1973 BC Hydro
R 26 kV, 3-Ph, Jacket 1969 PSEG
S 15 kV, 3-Ph, Jacket 1986 United Illuminating
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Cable Cross Sections
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Diagnostic Tests for Insulation Evaluation on
Terminated Cables

• Isothermal Relaxation Currents (IRC)
• Return Voltage Method (RVM)
• LIpATEST
• Dielectric Spectroscopy
• Harmonic Method

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Isothermal Relaxation Currents (IRC) Model KDA-1
from SebaKMT Sold in North America by HDW
Electronics
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Isothermal Relaxation Currents (IRC)
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Return Voltage Method (RVM)

• Automated measurement
• Charge _at_ 1kV dc for 30 minutes
• Quick discharge for 2-5 seconds
• Measure record return voltage for 30 min.
  (typ.)
• Discharge for 30 min.
• Charge _at_ 2 kV dc for 30 minutes
• Quick discharge for 2-5 seconds
• Measure record return voltage for 30 min.
  (typ.)

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Return Voltage Method (RVM) Model CD 31 made by
SebaKMT Sold in North America by HDW Electronics
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Return Voltage Method (RVM)
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LIpATEST Leakage Current pico amp
TEST LIpATEST service provided by Powertech Labs
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(No Transcript)
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Dielectric Spectroscopy Model IDA 200 from
Programma Sold by General Electric
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Dielectric Spectroscopy
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Harmonic Method
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Lead sheath diagnostic tests

• Rebound Hardness Tests
• Dye Penetrant Examination
• Eddy Current Examination
• In-Situ Metallography (Replica)
• Chemical Analysis of small samples

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Rebound Harness
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Rebound Harness
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Rebound Harness
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Fluorescent Dye Examination
Cracks on the Wrinkled Area of the Lead Sheath
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Eddy Current Dye ExaminationEstablished NDT
method usually applied to metal structures
Impedance-phase Diagram
Surface of the lead sheath
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In-situ Metallogaphic Examination
Replica of the surface structure taken on
acetate film
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In-situ Metallogaphic Examination
Micrograph of the lead directly
Micrograph of the Replica
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Chemical Tests on paper and oil samples

• Karl-Fischer Moisture Measurement
• Fourier Transform Infra-Red (FTIR)
• Fluorescence Measurements under UV Light
• Dielectric Thermal Analysis (DTA)

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AC break down tests
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AC break down test procedure

• All cables in ACBD test were 9 m long terminated
  with stress tubes
• Tested one phase at a time with other phases
  grounded
• Test started at two times normal operating
  voltage and held for 6 hours
• Voltage increased in steps equal to normal
  operating voltage
• At each step voltage held for 6 hours
• After each failure cable examined to determine
  were cable failed

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Water Ingress Test
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Water Ingress Test Procedure

• Cable P ( 1973) placed in tank under 1 m of tape
  water
• 3 phase connected in series for current cycling
• 330 A on for 8 hrs, off for 16 hrs
• 8 kv always on
• 12.5 cm slit cut in lead sheath for 1.5 months
• Slit enlarged to 1 cm by 12.5 cm hole
• Measure LIpATEST and RVM at intervals
• Monitor current and voltage for harmonic
  measurement

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Water Ingress test failure site
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REPORT
Available on EPRI.com Assessment of
Paper-Insulated Lead-Covered Cable Condition
Electrical, Chemical, and Metallurgical
Condition 1001724 - 2/25/2003