1. PSerc Lightning Protection: A Stroke of Luck? Theory and Application: Customer Side Low Voltage Systems Ward Jewell Wichita State University APPA 2005 ENGINEERING & OPERATIONS TECHNICAL CONFERENCE April 18, 2005 Power Systems Engineering Research Center

2. PSerc TV station $50k damage every year Transmitter

3. PSerc Transmitter

4. PSerc Lightning will strike n Lightning rods may help prevent burn damage to structures n Other devices may reduce number of strikes But…lightning will strike

5. PSerc Transmitter

6. PSerc Transmitter

7. PSerc Transmitter Poor tower ground

8. PSerc Poor Tower Ground Transmitter bends

9. PSerc Transmitter bolted connections Poor Tower Ground

10. PSerc Transmitter Poor Tower Ground

11. PSerc Transmitter high voltage Can we insulate?

12. PSerc Transmitter ~1,000,000 V Can we insulate?

13. PSerc Transmitter ~1,000,000 V Can we insulate? NO! voltage is too high

14. PSerc Lightning will flow to earth. Insulation will not stop it. Keep it away from sensitive equipment by giving it other paths to earth.

15. PSerc Improve tower ground Transmitter One ground rod close to each leg

16. PSerc Transmitter Exothermic weld (cadweld) conductors from tower to rods Improve tower ground

17. PSerc Transmitter Improve tower ground

18. PSerc Transmitter high voltage

19. PSerc Transmitter

20. PSerc Transmitter Bond tower grounds to building grounds

21. PSerc Transmitter Bond all grounds to service entrance ground

22. PSerc Transmitter high voltage

23. PSerc Transmitter

24. PSerc Transmitter Bond cable shield to tower

25. PSerc Transmitter high voltage

26. PSerc Transmitter Bond cable shield to building steel

27. PSerc Transmitter Surge suppression: everywhere a conductor enters the facility: secondary surge arrestors

28. PSerc Transmitter Surge suppression: everywhere a conductor enters the facility: secondary surge arrestors

29. PSerc Surge suppression: at sensitive equipment: transient voltage surge suppressors (UL 1449 listed) Transmitter

30. PSerc Provide all possible safe paths to earth; place surge suppression at the others Transmitter Bond cable shield to tower Improve tower ground Bond all grounds to service entrance building steel Surge Suppression

31. PSerc Transmitter Move service entrance to ground Or, even better, move all conductor entrances to one location at ground level, through grounded copper bulkhead.

32. PSerc Lightning Protection: Customer Side Low Voltage Systems n Lightning will strike –rods or other devices will not stop all strikes n Lightning will flow to earth –insulation will not stop it n Keep it away from sensitive equipment –Provide safe paths to earth –Bond all grounds –Use arrestors and suppressors »service entrance arrestors »sensitive equipment suppressors

33. PSerc ward.jewell@wichita.edu pserc.org APPA 2005 ENGINEERING & OPERATIONS TECHNICAL CONFERENCE April 18, 2005