DayCor ® Technology

1. DayCor® Technology Transmission

2. DayCor® Technology • DayCor® Technology is used to detect Corona Particle Discharge and Arcing • on electric grid components. • It offers you: • Early warnings of potential future failures. • Pinpointing & Visualizing the coronaeffect. • Decision ability to determines the health of your critical systems components • Prioritize your particle discharge maintenance challenges • Day time work • DayCor® Technologysaves you by avoiding costly • unscheduled outages and failures

3. -V e e + E field e UV Ph UV Ph UV Ph e + e e + e e Corona Effect Corona is a luminous partial discharge due air ionization. The DayCor® camera pinpoints the exact source’s location by visualizing the UV photons, coming out of it. UV Photon Natural Air molecule Free Electron, coming out from the source Corona Source

4. Bi-Spectral Imaging Combined mode Pinpointing the exact corona’s location Visible only display UV only mode

5. UV-IR complimentary technologies Live End Corona Dead End Corona Corona spots using UV technology No corona on IR picture

6. Corona is a concern because: It causes: • Degradation of polymer (NCI) insulators • Ceramic Insulator Defects • Physical damage to component. • Cracks the cement of pins and metal caps of porcelain insulators. • Audio noise (AN)

7. Degradation of polymer (NCI) insulators Corona Spot The outcome To get to that point is to waste your time & money Detect this failure in advance to take the right action on time

8. Ceramic insulators defects Component: 138 kV Insulator String Problem: First Insulator bell is damaged

9. Physical damaged to component Corona spots Left string- Outcome Right string - Outcome

10. Outcome Corona Spot Crack in cement and metal caps of porcelain insulators

11. Audio noise - few reasons

12. Audio noise - few reasons • Component: Connector on 138 kV Transformer Bushing • Problem: Sharp edges on connector cause radio and TV interference

13. Corona is a concern because: It indicates: • Possible Faults • Sealing defects • Shorted bells • Gap discharge • Loose hardware • Contamination • Corrosion or erosion • Broken Strands • Bad ground connections

14. Possible Faults Corona on the connection between the bushing and the capacitor. 138Kv Losing Energy it to lose Money !

15. Possible Faults Dead End Corona Leaking Current

16. Sealing Defects Ameren Indication The problem Hollow core insulator. The core should be sealed at the bottom with a cork/rubber plug. The cork/rubber plug was cracked compromising the seal. Without the seal, moist air was introduced into the hollow core. The dielectric properties of the insulator were changed affecting the electric field. The condition would eventually lead to insulator failure.

17. Sealing Defects play

18. Shorted Bells Pic 1: Corona on the 4th bell.Pic 2: Porcelain bells were replaced by glass bells due to being shorted 1 When you see corona at the middle of the insulator and the rest of it is clean check for short bells case 2

19. Gap Discharge

20. Loose hardware

21. Contamination Agricultural pollution Salt contamination agricultural pollution Polluted conductor

22. Corrosion or Erosion Corona spot due to erosion

23. Broken Strands

24. Bad ground connections

25. Can it be damaged by corona? AN, RI, TVI concern? Decision Chart Corona- where? Critical component? Yes No Material type Critical location? No Yes No Photons per Minute Yes No Low<1000 Corona intensity? 1000<Medium<5000 Yes High> 5000 Schedule repair or replacement Monitor for additional signs Repair or replace ASAP Repair or replace ASAP

26. No Corona Equipment at Normal conditions Low Counting Rate Medium Counting Rate Failure starts here Potential Failure High Counting Rate A Equipment fails to perform as expected Functionallyfailed B C D Outage Equipment broken Failure Process Condition