1. No category

Bushing Replacement Program
m aExp
Experiences
ny
p
m
o
C
2014 International Conference
nference
ringof Doble Clients
e
e
n
i
ng
April 6 - 11, 2014
Brady
E Duke Kate
e
l
Energy Progress
b
©Do Andre Lux, Sue Oxford, and Randy Jassmann
Doble Engineering Company
©2014 Doble Engineering Company. All Rights Reserved
Confidential Notice
• Doble Engineering (Doble) hereby grants the recipient (you) the right to
retain this presentation and materials included within (the Presentation) for
private reference. No other rights, title, or interest, including, but not limited
mit, display
disp
to, the rights to copy, make use of, distribute, transmit,
y or perform in
n
a
pany portion of the
public (or to third parties), edit, translate, or reformat
eformat
m
o
Presentation are hereby or otherwisee grante
granted
and shall remain expressly
g dCan
n
i
r
e
knowledge
reserved by Doble. You acknowledge
e and agree that such limited license is
n
i
g
n aacceptance of the terms herein. You
uponEyour
expressly conditionedd upon
e
l
b eevent of your breach, Doble will suffer irreparable
hat, inothe
further agree that,
D
© for which there is no adequate remedy at law. As such,
damage and injury
njury
Doble, in addition to any other rights and remedies available, shall be
entitled to seek injunction by a tribunal of competent jurisdiction restricting
you from committing or continuing any breach of these terms.
©2014 Doble Engineering Company. All Rights Reserved
2
Bushing Replacement Program Experiences
•
•
•
•
•
•
Description of individual programs
Failure histories
y
n
a
p
m
Program justifications
o
gC
n
i
r
e
e
Replacement bushings
ngs selected
n
i
ng
E
le
b
issu
Challenges and
issues
o
©D
Program status
©2014 Doble Engineering Company. All Rights Reserved
3
Bushing Replacement Program Descriptions
• Trench COTA High Voltage Bushings
– Draw lead / draw rod bushings
– Transformers
– All bushings rated 69 kV and above
• GE Type U Bushings
–
–
–
–
•
All GE Type U bushings
Transformers
Circuit breakers
Three phase voltage regulat
regulators
ng
i
r
e
ine
y
n
a
p
m
o
C
ng
E
le
b
o
D
©
Lapp PRC Bushings
hings
– Distribution class feeder breakers
– Three phase voltage regulators
– Manufactured prior to 1983
©2014 Doble Engineering Company. All Rights Reserved
4
y
n
a
mp
Trench COTA Replacement
Program
ring
le
b
o
D
e
e
n
i
ng
E
©
©2014 Doble Engineering Company. All Rights Reserved
5
Trench COTA - Bushing Description
– Draw lead/rod design,
hollow aluminum tube
– Un-insulated and
y
n
a
p
insulated copper
m
o
gC
n
i
conductor draw leads and
r
e
e
n
i
draw rods
ng
E
le
b
o
abo
– 69 kV ratings and
©Dabove
– 800 A – 1200 A
– All manufactured at Ajax,
Canada
©2014 Doble Engineering Company. All Rights Reserved
6
Trench COTA - Failures
• High and increasing failure
rates
y
n
a
p
m
o
• Progress Energy and utility
gC
n
i
r
industry experiencess nginee
E
e
l
b
o
• Deteriorating
ng©D
conditi
condition
• Age between 4 and 10 years
old
©2014 Doble Engineering Company. All Rights Reserved
7
Trench COTA - Failures
• 7 Failures over 8 years
• Transformer Types:
– Medium Power, 25 - 50 MVA – 6
– Generator Step-Up – 1
• Voltage Class
ng
i
r
e
e
– 230 kV – 6 (All in PEC)
n
i
g
– 115 kV – 1 (PEF) le En
b
o
• Transformer Manufacturers
nufacturer
D
©
– Waukesha – 5
– GE Prolec – 1
– Ferranti-Packard – 1
y
n
a
p
m
o
C
©2014 Doble Engineering Company. All Rights Reserved
8
Trench COTA - Population
Carolinas
• 82 Stations, 110 Transformers
• 319 bushings
–
–
169 bushings – 115 kV voltage class
150 bushings – 230 kV voltage class
g
rin
e
e
in
y
n
a
p
m
o
C
Florida
ng
E
le
b
o
• 57 Stations, 89 Transfo
Transformers
©D
• 239 Bushings
–
–
–
112 bushings – 69kV voltage class
34 bushings – 115kV voltage class
93 bushings – 230kV voltage class
©2014 Doble Engineering Company. All Rights Reserved
9
Trench COTA - Replacement Program Justification
• Safety of personnel and public
is a concern due to explosive
nature of failure
• Protection of transformer asset
ng
i
r
e
ine
y
n
a
p
m
o
C
– Most failures resulted in
ng
sform
er
due
destruction of the transformer
E
le
b
o
to fire
D
©
• Cost justification
– Cost of replacement program vs.
cost of continued failures
©2014 Doble Engineering Company. All Rights Reserved
10
Trench COTA - Replacement Challenges
•
Replacement bushing information
–
–
–
•
•
In very limited number of units, internal modifications necessary
With some transformer designs, no replacements aree avai
available
y
n
a
nded m
external
m
With some manufacturers, IEEE recommended
phasep minimum
o
phase clearances are encroached upon
ng C
ri
e if necessary
e
Extent of transformer modifications,
modifications
n
i
ng
E
Engineeringg Consider
Considerations:
oble ti
–
–
–
Tools
Materials
Training
©D
©2014 Doble Engineering Company. All Rights Reserved
11
Trench COTA – Replacement Bushings Selected
• Diversity of Manufacturers and Types
– Did not single-source
y
n
a
p
– Five different manufacturers selected
ected Com
ng
i
r
e
– Four types of bushingg constructio
construction
selected
gine
•
•
•
•
n
E (OIP) in silicone rubber housings
Oil impregnated
pregnated
paper
pape
e
l
b
o
OIP inn©
porcelain
poD
housings
RIP in silicone rubber housings
Solid dielectric epoxy
©2014 Doble Engineering Company. All Rights Reserved
12
Trench COTA – Issues Encountered
•
Internal and external encroachments encountered when
replacing with conventional OIP bushings
y
n
a
p
m
o
ansfo
rmers
– Internal Encroachments – 6 transformers
gC
n
i
r
e
e
n
i
ng – 18 transformers
– External Encroachments
oach
ments
E
le
b
o
•
Ranged
ged
from
¼”
¼
to 2 3/8” phase – phase
©D
©2014 Doble Engineering Company. All Rights Reserved
13
Trench COTA – Internal Encroachments
•
Start-Up Transformer – Draw Lead Bushings, 900 kV BIL
–
For Conventional OIP bushings:
•
•
•
•
Required to install pressboard barrier shield over the bushing’s
g s aluminum corona
y
shield
n
a
Required to install corona caps or washers onn existing
fi plate hardware
ompfitch
gC
n
i
r
e
Autotransformers (4) – Draw Rod
Bushings,
Bushin
900 kV BIL
e
n
i
g
n CT well
•
Too large for existing
sting CTs
C Eand
e
l
b appropriate conventional OIP bushings
•
OEM could
uld not
ident
identify
o
D
©
Distribution Class Transformer (1) Draw Rod Bushings, 550 kV BIL
•
•
Too large for existing CTs and CT well
OEM could not identify appropriate conventional OIP bushings
©2014 Doble Engineering Company. All Rights Reserved
14
Trench COTA – Installation Issues
• Discrepancies between transformer as-built drawings and
actual installation
y
n
a
– Internal shielding
p
m
o
gC
n
– Draw lead sizes
i
r
e
e
n
i
– Bushing types e Eng
l
b
o
D lead lengths
• Changes inn ©
dra
draw
– On-site brazing and crimping required
– Needed various size connectors available
©2014 Doble Engineering Company. All Rights Reserved
15
Trench COTA – Installation Issues
•
Storage, lifting, and handling
–
–
–
Manufacturer 1 – OIP in silicone rubber housing
–
–
–
Can be stored outdoors either horizontally or vertically
ousing
Cannot have ropes or slings in contact with housing
Lift by flange eyelets only – rotation hazard
a ard
–
Can be handled and lifted similar to porcelain bushing, with some constraints
y
n
a
mp
o
C
g
Manufacturer 2 – RIP in silicone
liconeerubber
rubbe
rin housing
e
–
Storage – indoors
rs if n
notginin
sea
sealed bag
E
on – bushings
bushin
c
–
Option
in sealed, air-tight metal coated bags. Can be kept in
e s come
l
b
o
bags
agsD
© for up tot 20 years with no concern of degradation of lower end by moisture.
Manufacturer 3 – Solid epoxy bushing
–
–
For extended periods of time, store indoors
Can be handled and lifted as any porcelain bushing
©2014 Doble Engineering Company. All Rights Reserved
16
Trench COTA – Program Status
•
Progress Energy Carolinas
–
–
–
Replaced bushings in approximately 80 transformers
y
n
a
ain mp
Approximately 30 transformers remain
o
C
g
Anticipated program completion
mpletion
erinin 2014
–
–
Approximately 51 transformers remain
Anticipated program completion in 2015
e
n
i
g
En
• Progress Energy
nergy
Florida
F
lorida
e
l
b
o
D
– Replaced
ed©bushings
b
in approximately 46 transformers.
©2014 Doble Engineering Company. All Rights Reserved
17
y
n
a
mp
GE Type U Replacement
Program
ring
le
b
o
©D
e
e
n
i
ng
E
©2014 Doble Engineering Company. All Rights Reserved
18
GE Type U – The Problems
• Ink lined paper design
– Increasing power factor
• Flex seal design
g
rin
– Compromised gaskets
e
e
in
g
n
– Hot spots
le E
y
n
a
p
m
o
C
b
o
D
©
• Slip seal design
ign
– Top terminal overheating
©2014 Doble Engineering Company. All Rights Reserved
19
GE Type U - Failure History
• 1990’s
– Formal replacement program for medium voltage bushings in transformers and
voltage regulators
– Approximately 80% of installed fleet were replaced at that time
ny
• 1990’s and Early 2000’s
a
p
m
Co
ngtto increasing power factor
– Few failures of 115kV but some replacedridue
• Recent Years
e
e
n
i
ng
E
– Two 230 kV transformer
lebbushing failures
b
o
ngs
re
– More bushings
required replacement annually due to increasing power factor and
©D
capacitances
• Internal study determined that, as a population, power factor was increasing
significantly
©2014 Doble Engineering Company. All Rights Reserved
20
GE Type U - Program Justification
• Safety of personnel and public
• Reliability and protection of equipment
y
n
a
p the
ures
t history with
• Sensitivity to high voltage bushing failures
given
m
o
gC
n
Trench COTA failures
i
r
e
e
n
i
ngO&M
• Policy changess regard
regarding
ding
O& versus capital replacements
E
e
l
b
o
D
©
• Identified approximately
pproxi
800 GE Type U bushings on
transformers, transmission class oil-insulated circuit breakers,
and voltage regulators
©2014 Doble Engineering Company. All Rights Reserved
21
GE Type U - Replacement Program Description
• Decision made to replace Type U Bushings as part of life
extension/equipment health program
– Transformers
– Circuit Breakers
– Three Phase Voltage Regulators
o
C
ring
e
y
n
a
mp
ine included in replacement
• All Type U and Type OF nbushings
bushing
g
E
e
program
l
b
Do
©
• If equipmentt w
was identified for replacement as part of formal
equipment replacement program, the bushings would not be
replaced
©2014 Doble Engineering Company. All Rights Reserved
22
GE Type U – Replacement Bushings Selected
• Diversity of Manufacturers and Types
– Did not single-source
y
n
a
p
– Four different manufacturers selected
e ted Com
ng
i
r
e
– Three different typess of bushings
gine selected
•
•
•
n
E
OIP in porcelain
hhousings
ous
e
l
b
o
RIP inn©
ssilicone
liD rubber housings
Solid dielectric epoxy
©2014 Doble Engineering Company. All Rights Reserved
23
GE Type U - Program Status
• Identified approximately 800 GE Type U bushings on
approximately 190 transformers, transmission class oily
regulato
insulated circuit breakers, and voltage regulators
n
a
p
m
o
• Program started in 2011
gC
n
i
r
e
e
n
i
• Replaced bushings
g innE87
transformers, 13 regulators, 5
ngtrans
le
b
circuit breakers
kers
o
©D
• Approximately 87 pieces of equipment remain
• Anticipated completion in 2018
©2014 Doble Engineering Company. All Rights Reserved
24
y
n
a
mp
Lapp PRC Replacement
Program
ring
le
b
o
D
e
e
n
i
ng
E
©
©2014 Doble Engineering Company. All Rights Reserved
25
Lapp PRC – The Problem
• In the 1980’s, Lapp identified a
manufacturing issue that
resulted in moisture ingress to
y
n
the bushing, leading to eventual
a
p
m
o
failure
gC
n
i
r
• Bushings were manufactured
ed inee
between 1967 and 1983
983e Eng
l
b
o
• A field modification
ation
to
th
the
©D
bushings was recommended
and Progress Energy
implemented these modifications
to a portion of its installed fleet
©2014 Doble Engineering Company. All Rights Reserved
26
Lapp PRC - Failures
• Low failure rate until ~2005
• Not all failures could be
y
attributed to the identified
n
a
p
m
moisture issue
o
gC
n
i
r
e
• Failure rate increased
e
n
i
ng
E
dramatically over
er period
le
b
o
2005 – 2011 ©D
• Implemented system-wide
program to replace all pre1983 PRC bushings
©2014 Doble Engineering Company. All Rights Reserved
27
Lapp PRC Bushing Failure History, 2007 - 2012
14
12
y
n
a
omp
10
8
ng
i
r
e
ine
6
C
ng
E
le
b
o
D
©
4
2
0
2007
2008
2009
2010
2011
2012
Aggressive Replacement
Program Started
©2014 Doble Engineering Company. All Rights Reserved
28
Lapp PRC – Program Justification
• Safety of personnel and public
• Increasing failure rate resulting
y
n
in excessive customer minutes out
a
p
m
o
• Bushings installed in almost 600 ring C
e
e
n
i
12 and 23 kV circuitt breakers
reakers
ng
E
le
b
o
manufactured
ed©by
ITE
and Allis Chalmers
D
• Policy changes regarding O&M versus capital replacements
• Opportunity to change to non-porcelain designs
5,000,000
4,000,000
C…
3,000,000
2,000,000
1,000,000
0
©2014 Doble Engineering Company. All Rights Reserved
29
Lapp PRC – Replacement Bushing Selection
• Dry-type bushings in nonceramic housings
y
n
a
p
• Did not single-source
m
o
gC
n
i
r
• Two vendors selected inee
ng
E
leutility
rmedoby
utilit
• Work performed
b
D
t crews
and contract©
• No sight glass issues
©2014 Doble Engineering Company. All Rights Reserved
30
Lapp PRC - Issues Encountered
• High failure rate experienced with one of the replacement
vendors –
– Five failures in 18 months
y
n
a
– Time in service ranged from two months to seven
years
mp year
o
C
g
• RCA conducted with manufacturer,
cturer,
results inconclusive
rinre
e
e
in in
g
a ing
• Discontinued purchasing
and
installing remaining stocked
n
E
le
bushings from
om D
this
ma
until issue is clearly
bmanufacturer
o
understood, ©
res
resolved, and a solution has been identified
• Approximately 50 breakers (300 bushings) have this
manufacturer’s bushings installed
©2014 Doble Engineering Company. All Rights Reserved
31
Lapp PRC - Program Status
• Identified 3,600 bushings on 600 medium voltage circuit
breakers
y
n
a
p
• Program began in 2011
m
o
gC
n
i
r
e bbreakers
• Replaced bushings inn 525incircuit
e
ng
E
le cu breakers remain
tely 75
cir
• Approximately
circuit
b
o
©D
• Anticipated completion by December, 2014
©2014 Doble Engineering Company. All Rights Reserved
32
y
n
a
p
Thank you for your kindomattention!
gC
n
i
r
e
e
n
i
ng
E
le
b
o
©D
©2014 Doble Engineering Company. All Rights Reserved
33