Transcript Slide 0

Overview & Benefits of
Thermographic Inspection
SWEDE Conference
Michael Navarro
May 2007
Oncor Electric Delivery
WHAT IS THERMOGRAPHY?
Infrared (IR) radiation is electromagnetic radiation of a wavelength
longer than that of visible light, but shorter than that of radio waves.
The name means "below red" (from the Latin infra, "below"), red
being the color of visible light of longest wavelength.
Infrared radiation is popularly known as heat, heat radiation, or “hot
spots”.
Infrared radiation can be used to remotely determine the temperature
of objects. This process is commonly called “Infrared” in the electric
utility industry.
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Benefits of Thermographic Inspections
Proactive thermographic inspections on Transmission and Distribution
systems have proven:
 Improvement in our SAIDI and SAIFI metrics
 Reduced equipment failures, resulting in less capital spend
 Reduction in O&M spend as a result of less reactive restoration,
usually during overtime hours.
 Improved reliability, or more specifically, a reduction in outages has
a positive impact on customer satisfaction
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Recommendations for Targeted
Inspection
 Transmission Substation and equipment inspection
 Distribution feeder main line inspection that is accessible by vehicle
– Arresters, air switches, voltage regulators, capacitor banks,
connectors, fused disconnects, insulators, solid disconnects,
transformers, regulators, reclosers, riser pole terminations
– Major Equipment - Switchgear, three-phase transformers, auto
transformers, automatic transfer equipment, walk in vaults.
Manholes are not included because of OSHA requirements for
working in manholes
 Special Request/Event inspections
– Sporting events, convention facilities, fairgrounds, and any
televised event
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Recommendations for Targeted Inspection
(Cont.)
 Government Facilities, Hospitals, Water Supply
 Emergency infrared inspections can be utilized as a trouble
shooting tool
 Additional component of the Infrared Inspections is a detailed
report which includes:
– Delta T or Ambient temperature
– FLIR software and reporting tools
– NETA (National Electrical Testing Association) priority rating
criteria
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Oncor Electric Delivery’s History
1970’s
 Nitrogen cooled camera held out of truck window
1993
 Oncor system wide central program established with a Technical
Services group.
 Infrared inspect 2700 feeders & 800 substations per year
1999 - 2001
 EPRI Project
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Oncor Electric Delivery’s History (Cont.)
2001
 Transmission began inspection of substations
 Improved quality by inspecting 1/3 of feeders
 Optimized methodology identifying “hot spots”
2002
 Performance Based Inspection (10% Worst Performing Feeders)
 Overhead and Underground Facilities inspected
2003
 Performance Based Inspections produced a higher % of hot spots
with a higher priority rating while scanning fewer feeders
 Spot checking new terminations
 Added portable cameras
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Oncor Electric Delivery’s History (Cont.)
2004
 Performance Based Inspections continued and more Underground
Distribution facilities targeted
2005
 Performance Based Inspections increased (20% WPF)
 Additional Underground Distribution facilities targeted
 $500,000 for Infrared Inspections contracted outside of company
2006
 Performance Based Inspections continue
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When to Perform Thermographic Inspections?
Thermographic Inspections can be performed year round
 Delta T process for Infrared allows this by using temperature rise
over reference equipment rather than rise over ambient
 Winter peaking feeders can be targeted
 High visibility on darker days helps to identify anomalies
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Criteria for Determining the Priority Rating for
Repair
 Consumers Affected
– The estimated number of consumers that may be affected
and the type of equipment affected is taken into
consideration. By using this information and the temperature
of the hot spot along with the Thermographer’s experiencedbased knowledge, the anomaly will be rated.
• Priority 1…..low priority
• Priority 2…..low priority
• Priority 3…..work as you can
• Priority 4…..within 24 hours (high priority)
• Priority 5…..repair immediately (safety or imminent outage)
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What Criteria Determines the Priority Rating
For Repair?
 Wind
– If the wind is greater than 15 mph, it will reduce the
temperature measured by half. Wind speed will be measured
by using either an instrument located on the truck or by local
weather forecast Load and Time
 Load and Time
– The Load and Time of day will help determine the probability
that as the day progresses the load will increase and the
temperature of the hot spot will also increase. The
Thermographer will use experience based knowledge and
available data to derive at the grading of this priority
 Safety Concerns
– If there is a Safety Concern the hot spot will then be
considered as a Priority 5 – repair immediately
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Benefits
There are several benefits for performing Infrared Inspections on the
electrical system.
 Enhanced operational safety and reliability of the system
 SAIDI/ SAIFI improvements




Increased material and equipment life, resulting in capital savings
Proactively identifies workmanship issues
Maintenance cost reduced by preventing unscheduled outages
The only predictive maintenance available (***)
 Saves you money
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Equipment Required to Support Thermography
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Equipment Required to Support Thermography
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Equipment Required to Support Thermography
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Equipment Required to Support Thermography
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Equipment Required to Support Thermography
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Equipment Required to Support Thermography
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Examples
212.5 degrees C
Temperature of Hot Spot –239.2 degrees C – Solid blade disconnect switch
Temperature of Spot 1 –26.7 degrees C – Solid blade disconnect switch
Delta T temperature – 212.5 degrees C – rise above reference
OUTAGE OCCURRED PRIOR TO REPAIR INVOLVING 203 CUSTOMERS FOR 3 HRS 2 MIN FOR 36,945 CUST MIN
INFRARED INSPECTION PERFORMED 5-11-05 AND EQUIPMENT FAILED 7-23-05
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Examples (Cont.)
54.2 degrees C
Temperature of Hot Spot –86.3 degrees C – Solid blade disconnect switch pothead connection on 2 phases
Temperature of Spot 1 –32.1 degrees C – Solid blade disconnect switch
Delta T temperature – 54.2 degrees C – rise above reference
OUTAGE OCCURRED PRIOR TO REPAIR INVOLVING 1590 CUSTOMERS FOR UP TO 2 HRS 52 MIN
FOUR STAGE RESTORATION FOR 190,186 CUSTOMER MINUTES
INFRARED INSPECTION PERFORMED 6-8-05 AND EQUIPMENT FAILED 7-14-05
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Examples (Cont.)
79.6 degrees C
Temperature of Hot Spot –118.4 degrees C – Air Break Switch Middle Phase
Temperature of Spot 1 –38.8 degrees C – Air Break Switch
Delta T temperature – 79.6 degrees C – rise above reference
OUTAGE OCCURRED PRIOR TO REPAIR INVOLVING 2398 CUSTOMERS FOR UP TO 1 HRS 1 MIN
TWO STAGE RESTORATION FOR 27,588 CUSTOMER MINUTES
INFRARED INSPECTION PERFORMED 6-27-05 AND EQUIPMENT FAILED 7-4-05
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Examples (Cont.)
Temperature of Hot Spot – 53.1 degrees C – blade of switchgear
Temperature of Spot 1 – 42.6 degrees C – reference blade of switchgear
Delta T temperature – 10.5 degrees C – rise above reference
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Examples (Cont.)
Temperature of Hot Spot – 81.5 degrees C – capacitor oil switch
Temperature of White Arrow Spot – 41 degrees C – reference capacitor oil switch
Delta T temperature – 40.5 degrees C – rise above reference
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Examples (Cont.)
Temperature of Hot Spot – 142.5 degrees C – H squeeze connection
Temperature of White Arrow Spot – 33.6 degrees C – reference H squeeze connection
Delta T temperature – 108.9 degrees C – rise above reference
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Examples (Cont.)
Temperature of Hot Spot – 66.5 degrees C – elbow connection
Temperature of Spot 1 – 39.3 degrees C – reference elbow connection
Delta T temperature – 27.2 degrees C – rise above reference
INDIRECT HOT SPOT – WHILE REPAIRING, THE ELBOW CRUMBLED IN THE HANDS OF THE WORKER
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Examples (Cont.)
Temperature of Hot Spot – 32.5 degrees C – All 3 terminations
Temperature of Spot 1 – 27.7 degrees C – reference top of termination
Delta T temperature – 4.8 degrees C – rise above reference
HOT SPOTS THAT APPEAR TO BE WHERE THE SEMI-CON IS CUT TOO DEEP DURING PREPARATION IS
ACTUALLY A TERMINATION APPLIED INCORRECTLY ALLOWING A VOID THAT CREATES PARTIAL DISCHARGE
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Examples (Cont.)
Temperature of Hot Spot – 59.6 degrees C – All Arresters
Temperature of Spot 1 – 27.3 degrees C – Primary Bushing
Delta T temperature – 32.3 degrees C – rise above reference
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History - Ranking of “Anomalies”
YEARLY PRIORITY TOTALS
1500
1000
500
0
Oncor Electric Delivery
Priority
5
Priority
4
Priority
3
Priority
2
Priority
1
Total
2002
76
327
65
199
29
696
2003
113
798
696
72
5
1684
2004
119
860
1048
34
0
2061
2005
251
867
1474
70
0
2662
2006
85
477
985
2
0
1549
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History - Identified “Anomalies” by Device
Infrared Inspection Items
Equipment
ATO
Air Break Switch
Arrester
Capacitor
Capacitor Oil Switch
Disconnect Switch
Fused Cutout
Insulator
Manhole
Meter CT - Primary
Pothead
Primary Feeder
Recloser
Regulator
Secondary and Services
Switchgear
Transformer
UG Terminations
Vacumn Switch
Weather heads
Oncor Electric Delivery
2002 Total
0
138
336
22
65
211
173
1
0
6
50
130
13
13
8
16
75
0
0
3
2003 Total
4
178
451
21
58
284
152
1
2
4
44
174
12
42
0
122
133
0
3
2
2004 Total
1
212
525
48
68
362
215
5
0
7
63
178
13
18
45
33
184
80
1
3
2005 Total
2
230
707
27
86
329
248
1
0
4
91
191
10
7
76
183
188
281
0
1
2006 Total
1
139
459
26
25
199
169
0
0
2
34
169
15
10
25
61
87
106
0
0
1259
1687
2061
2662
1549
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History - Identified “Anomalies” by Device (Cont.)
YEARLY COMPARISON - INFRARED INSPECTIONS
800
700
600
500
400
300
200
100
0
2004 Total (2061)
2005 Total (2662)
2006 Total (1549)
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History - 2006 Identified “Anomalies”
2006 INFRARED INSPECTION DATA
Air Break Sw itch
Air Break Sw itch , 139
Arrester
459
ATO, 1
Capacitor , 26
Capacitor Oil Sw itch , 25
Arrester
ATO
Capacitor
Capacitor Oil Sw itch
Disconnnect Sw itch
Disconnnect Sw itch , 199
Fused Cutout , 174
Fused Cutout
Insulator , 0
Manhole, 0
Meter CT - Primary , 2
Pothead , 34
Insulator
Manhole
Meter CT - Primary
Pothead
Primary Feeder , 169
Recloser , 15
Regulator , 10
Secondary and Services, 42
Sw itchgear, 61
Transformer , 87
UG Terminations, 106
Vacumn Sw itch, 0
Weatherheads , 0
Primary Feeder
Recloser
Regulator
Secondary and Services
Sw itchgear
Transformer
UG Terminations
Vacumn Sw itch
0
100
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200
300
400
500
Weatherheads
30
History - 2005 Identified “Anomalies”
2005 INFRARED INSPECTION DATA
Air Break Sw itch
Air Break Sw itch 230
Arrester
Arrester 707
ATO 2
Capacitor 27
Capacitor Oil Sw itch 86
ATO
Capacitor
Capacitor Oil Sw itch
Disconnnect Sw itch
Disconnnect Sw itch 329
Fused Cutout 248
Fused Cutout
Insulator 1
Manhole 0
Meter CT - Primary 4
Pothead 91
Insulator
Manhole
Meter CT - Primary
Pothead
Primary Feeder 191
Recloser 10
Regulator 7
Secondary and Services
76
Sw itchgear 183
Transformer 188
UG Terminations 281
Vacumn Sw itch 0
Weatherheads 1
Primary Feeder
Recloser
Regulator
Secondary and Services
Sw itchgear
Transformer
UG Terminations
Vacumn Sw itch
0
100
200
Oncor Electric Delivery
300
400
500
600
700
800
Weatherheads
31
Questions?
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