Presentation OFIL DAYCOR II - CAMERA CORONA.ppt
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This document provides an overview of Ofil Ltd., a company that develops and manufactures daytime UV inspection systems. It describes their DayCor®II technology, which uses a solar blind filter and bi-spectral imaging to detect corona, partial discharge, and arcing on electric grid components during full daylight. The document outlines the key features and advantages of the DayCor®II system, such as its ability to pinpoint the exact location of issues and help utilities prioritize repairs. It then provides several examples of how utilities have used the DayCor®II camera to detect and locate corona and other problems on a variety of electric grid assets, including high voltage transmission lines, substations, and distribution lines.
Presentation OFIL DAYCOR II - CAMERA CORONA.ppt
- 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
- 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
- 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
- 78. Poor Grounding Connection Allegheny - Pole fire investigation 25 kV 69 kV substation
- 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