Presentation OFIL DAYCOR II - CAMERA CORONA

1. Ofil Ltd.
Today’s Leading
Developer and
Manufacturer of
Daytime UV
Inspection Systems
for the Utility
Marketplace

2. Headlines
o Technology Overview
o Main Features
o The OHT Inspection Guide
o Applications

3. Using the DayCor®II
Technology to Detect
Corona, Partial Discharge
and Arcing on Electric Grid
Components

4. DayCor®II technology
can help you
• DayCor®II Camera can provide you with
an early warning of potential failures.
• Determine the health of your critical
system components and prioritize repair
and replacement tasks.
• DayCor®II Camera is helping
utilities avoid costly unscheduled
outages and failures.

5. Until now…
DayCor®II camera makes detection
of corona on damaged transmission,
distribution and substation
equipment, a routine and cost
effective part of your preventive
maintenance program.
Corona detection efforts were
generally limited to the hunt for
audible noise and radio
interference problems or by
night vision cameras.
Now…

6. Advantages of DayCor®II
 Detects corona, partial discharge and arcing
under all light conditions including full
sunlight.
 Pinpoints the exact location of the corona,
eliminating the expensive process of
guessing which component is damaged.
 Optimization of insulator washing cycle
 Performance is totally unaffected by
lighting conditions.
 Sensitivity does not change with lighting.
 Quantifies the intensity of corona.

7. Operations Using
DayCor®II...
 Are safer, faster and less expensive than
operations in low light or at night.
 Permit use of both ground and airborne
inspections with the highest level of safety
and least number of restrictions.
 Avoids the premium labor rates required
for operations during nighttime hours.
 Easy to adapt as a routine procedure.

8. Corona is a concern because
Degradation of Insulators
Physical Damage to Components
Radio Interference
Audio Noise
Indication for possible fault
Indication for improper installation
Indication for washing
effectiveness
Indication for imminent
flashover or tripping
Ofil

9. What Is a Corona ?
A high local electric field
ionizes the air and causes a
discharge.
This process is accompanied
by excitation of Nitrogen
molecules, leading to
emission of UV radiation

10. E field
Impact of electrons with neutral molecules
results in creation additional electrons,
positive ions and emission photons
Buildup of ionization occurs only if
electron is going fast enough, i.e. if
electric field exceeds a critical value
-V e +
-
-
-
Thus a problem or defect in a component
creating a local high electric field will show
corona activity.
+
+
-
-
-

11. Sources of Corona and Arcing
• Broken Strands
• Loose Hardware
• Pollution
• Shorted Bells on Insulators
• Improper Installation
• Damaged Insulator
• Bad Ground Connection
• Gap discharge EPRI
EPRI
EPRI
EPRI

12. Corona Is Mainly a
Concern From
Maintenance and
Operation
Perspective!

13. Typical Corona
Emission Spectrum
Corona discharges
emit UV radiation
from 230nm to
405nm.
The Corona
radiation between
240-280nm can be
detected by the
DayCor camera at
full sunlight, due to
Ofil’s solar blind
filter.
Corona radiation
500
400
300
200 0
50
100
x100
Relative
Intensity
Wavelength (nm)
Solar Blind Filter band

14. Solar Blind Filter and Solar Radiation
Solar Blind Filter and Solar Radiation
Filter
Transmission
(%)
Wave length (nm)
UV Visible IR
200 300 400 500 600 700 800 900 1000
20
40
60
80
100
120
140
2
4
6
8
10
12
Solar
Radiation
(µW/cm
2
/nm
)
C B A

15. Goal: To detect and locate corona on HV transmission
lines and substations components
Principle: Bi-spectral imaging using solar blind UV filter
technology to detect corona and visible imaging of the
surrounding scene
UV channel detects corona
Visible channel locates corona source
Visible
camera
UV camera
Visible
lens
UV lens
Final
image
Solar blind
filter
Image
mixer
UV beam splitter
light
CCD camera

16. Some Customers (Utilities)
TVA-Tennessee Valley Administration 4 units
NYPA-New York Power Administration 2 units
Bonneville Power Administration 1 unit
National Grid (UK) 1 unit
East Kentucky Power Cooperative 1 unit
Allegheny Power 1 unit
City Public San Antonio 1 unit
Central Hudson Gas and Electric 1 unit
Consolidated Edison (ConEd) 1 unit
TXU Electric 1 unit
BGE-Baltimore Gas & Electric 1 unit
SDG&E- San Diego Gas &Electric 1 unit
About 70 units were sold world wide.

17. Main Features
A Real-Life Solution
Totally solar blind Full daytime capability – all
lighting conditions
Compact & lightweight design for 5º FOV
Long Detection Range: More Than 250m
(50 m flight distance from lines - The Most Sensitive Solar Blind UV Optics Known Today)
Highly Ergonomic:
Hands-free Stress-free Vest Style
High Brightness LCD
(safety and continues line of sight)
Full Auto Focus – Both UV
and Visible
Real time Video – no digitization

18. Ruggedized (Mechanics and Optics) and
splash proof
Adjustable UV Gain And Exposure –
Better Visibility
Enhanced Detectivity – Long Integration
UV Event Counter –estimation of Corona
strength
Visible Zoom
X2 Optics X8 Digital
All Metal Case EMI Resistant
Main Features
A Real-Life Solution
Ofil

19. A Breakthrough
Technology
InfraRed
UltraViolet
ΔT - Hot Spots – Not Corona!
(Internal Phenomenon)
Detects Corona, Partial
Discharge & Arcing
(External Phenomenon)
Current Dependent
(Heavy Line Loading)
Voltage Dependent Only
(No Line Loading)
Solar Radiation and Hot
environment set a problem
All Lighting & Weather
Conditions
(humidity is an advantage)
Detection Usually at
Progressive Stage of
Degradation
Detection at Earlier of
Degradation
(i.e. Commissioning)
Additional Software for Post-
processing is Needed (ΔT)
Post processing software is not
required

20. The UV and IR are not competitive but
complimentary technologies!
The DayCor®II Technology Enables
Utilities for the First Time to Break Into
the Unexplored Area of Daytime UV
Inspection, Leading to Higher
Performance and Reliability of the
Electric Grid
A Breakthrough
Technology
SDG&E

21. Inspection Methods
Ground patrol 
Airborne 
Van mounted
Pan & tilt head
EPRIsolutions
SDG&E
Ofil

22. Polytech’s Airborne System:
Corona 350-I
Airborne Advantages:
• covering long distances
• Overcoming topographic
barriers
• Speed
• safety
Corona (DayCor®II)350-I
• First production – mid 2002
• Already proved cost effective
• In use by three users in Europe
and in US
• In transmission and
• In Distribution
DayCor®II camera
in gyro
stabilized gimbal

24. Courtesies
to EPRI:
Guide to
Corona
and Arcing
Inspection
of
Substation

25. Corona
inspection
Concerns
and
Examples

28. Terminations
Internal
structure
generates
external corona

29. Terminations
Transformer
30kV/400V

30. …Corona around the pin will slowly lead
to erosion of the pin cement, which can
lead to a separation failure.
Corona between the cap and the shell
will either lead to puncture of the
porcelain dielectric or a "doughnut" type
of failure
“Outdoors Insulators” by Dr. Ravi Gorur
Arizona State University
Outdoors Insulators

31. Cement Erosion
Corona around the pin will slowly lead to
erosion of the pin cement ,which can lead to a
separation failure

32. Cracked /Eroded cement
“If undetected corrosion proceeds to
the point of mechanical failure
resulting in dropped conductors”

33. Arcing Short
Insulators
Shorted; held
approx. 8-10 kV,
then arcing
started

34. Porcelain Suspension
Insulator Crack in Cap
Region

35. Transmission System
Application
“Pin and Clevis” on a 500 kV Line
8 structures
In 5 hours!
28 Years Old
Line

36. Internal Short
Between the pin and the cap

37. Internal Short

38. Arcing Short
Reduced Gain Images of 500 kV Insulators

39. Arcing Short
Electric and
Mechanical
Problem

40. Arcing Short
500 kV line
Same tower,
other phase note
replaced bells

41. Pin Corrosion of Glass
Insulators
Corrosions
leads to corona
Corona
contributes to
corrosion of
metal parts
Consequentially in the long
run there is erosion of the pin
and dropping of the line.

42. Pin Corrosion of Glass
Insulators
“If undetected, corrosion proceeds
to the point of mechanical failure
resulting in dropped conductors”.

43. Pin Corrosion of Glass
Insulators

44. contamination
The salt from the sea, the sand
from the desert, the air pollution
which every developed society
produces - can all settle on
exposed high voltage insulators
producing leakage currents with
the risk of flashover and
consequent loss of supply, our
DayCor camera can detect
easily, contaminated elements.

45. contamination
• Contaminants, leads to
uncontrolled leakage current
• High Leakage current leads to
flash over
• Flash over leads to punchers and
outages
• Low Leakage current leads to
erosion in highly, contaminated
areas, pin erosion on both
porcelain and glass insulators
have caused lines to drop

47. contamination

49. Salt contamination on
glass insulator
In the presences of contaminants , an
uncontrolled leakage current sometimes
develops into flashover

51. contamination

52. Eurotunnel Electrical
Train Line inspection
• The problem:The proximity to the sea
causes a high level of salt contamination
on the insulators and cables
• In October 2002 the trains travelling UK -
France stopped all of a sudden
• To reactivate the trains an immediate
washing of one side of the line was
ordered. Apparently, this procedure was
awkward and lengthy since the
maintenance team could not pinpoint with
its instruments the contaminated spots,
and had to clean all along the whole line.

54. Eurotunnel Electrical
Train Line inspection
As a result, the DayCor®II representative in
France was commissioned to check the
quality of the washing. Using the DayCor®II
camera it became immediately evident which
side of the line was washed, and exactly
which of the washed insulators were not
properly washed and had still corona and
arcing activity on them. Furthermore, with the
DayCor®II camera mounted on the washing
railway trailer C&M pointed out to the
washing team which of the insulators needed
urgent and high priority washing

55. Eurotunnel Electrical
Train Line inspection

56. Optimization of insulator
washing cycle
The DayCor can help determine whether to
wash or replace contaminated components.
The DayCor can detect if the insulator has a
risk of flashover higher than acceptable and
therefore needs washing.
The duration between washing may be
extended or reduced. In turn ,this will result
in either maintenance cost reduction or
avoided outage

61. Rusted and Loose
Hardware 20 Kv Line

62. Substation

63. Capacitor bank
138 kV
Capacitor Bank
Inspection
Replace
defected unit

64. Corona on bar 500 kV
substation

65. Loose metal cap
Mechanical problem - Remove for
service

66. Loose metal cap
Mechanical problem - Remove for
service

67. Loose metal cap
345 kV substation - The system had a lot of motion
in it so the corona phenomenon is intermittent and
probably a beginning of a crack.

68. Loose metal Sleeve
Moisture penetration - Remove for
service

69. Cracked porcelain post
Mechanical problem, Moisture
penetration - Remove for service

70. Cracked porcelain post
Mechanical problem, Moisture
penetration - Remove for service

71. Voltage: 230kV
Defect: Bushing grounding collar spring damaged
Issue: Potential catastrophic failure
Image by Paul F. Lyons

73. And now the DayCor®II technology
is used even for Distribution Lines
(Results even on 10 kV components)
Switches & Transformers
Pole Tops And Hardware
Connectors
Insulators
Cracked fuse carrier
Distribution System
Application
STRI
C&M
C&M
Ofil

74. Pedestal post insulator
Check thoroughly
11 kV
31.5kV

75. Distribution Application
13.4 kV
34 kV 23 kV

76. Cracked Pin Insulator
11 kV, 30 years
old, Caused 3
outages on the
first rain

77. Cracked Pin Insulator

78. Poor Grounding
Connection
Allegheny - Pole fire investigation 25 kV
69 kV substation

79. Poor Grounding
Connection

80. Bad Connection of the
Conductor to the Insulator,
33kv Line in the UK

81. Cracked insulators
33kV line in the UK

82. Bad connection to the
bus bar

83. Faulty Installation
Industry Confidential
This is a new line. It trips out for
unknown reasons. The image was
recorded midday. The line trips mainly
in the morning. Flashing was
observed on all phases, the
grounding wire was installed
improperly with induced voltage.
The subcontractor was supposed to
attach it to 1 point but attached it
to 2. After the utility personnel saw
the corona, they realized the
problem instantly.

84. Motor 6.6 kV
1200 HP
After repair
5500 pC at
3.8 kV
IEC
Other Applications
Testing Partial Discharge in
electric Motor

85. MOTOR 6.6 kV
2500 HP
After repair
14000 pC
at 3.8 kV
Other Applications
IEC
Testing Partial Discharge in
electric Motor

86. Application Information
Availability
DayCor UV Inspection Training Is Available From EPRI (More Than
15 Courses on 2001)
A Users-group-meeting of the DayCor Users is annually held for
USA utilities (Last One Was Held on November)
Utility Information Sharing (Seeing Corona)

87. Additional Application
Information Sources
STRI - Sweden
VEIKI-VNL - Hungary
IIE – Mexico
EPRI - USA
CESI