Embed Size (px)
DESCRIPTION
Lightning Protection: A Stroke of Luck? Theory and Application: Customer Side Low Voltage Systems. APPA 2005 ENGINEERING & OPERATIONS TECHNICAL CONFERENCE April 18, 2005. Ward Jewell Wichita State University. Power Systems Engineering Research Center. - PowerPoint PPT Presentation
Citation preview
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 CONFERENCEApril 18, 2005
Power Systems Engineering Research Center
PSerc
TV station$50k damage every
year
Transmitter
PSerc
Transmitter
PSerc
Lightning will strike
Lightning rods may help prevent burn damage to structures
Other devices may reduce number of strikes
But…lightning will strike
PSerc
Transmitter
PSerc
Transmitter
PSerc
Transmitter
Poortower
ground
PSerc
Poor Tower Ground
Transmitter
bends
PSerc
Transmitter
boltedconnections
Poor Tower Ground
PSerc
Transmitter
Poor Tower Ground
PSerc
Transmitter
highvoltage
Can we insulate?
PSerc
Transmitter
~1,000,000 V
Can we insulate?
PSerc
Transmitter
~1,000,000 V
Can we insulate?NO!
voltage is too high
PSerc
Lightning will flow to earth.
Insulation will not stop it.
Keep it away from sensitive equipment
by giving it other paths to earth.
PSerc
Improve tower ground
TransmitterOne groundrod close to each leg
PSerc
Transmitter
Exothermicweld
(cadweld)conductorsfrom tower
to rods
Improve tower ground
PSerc
Transmitter
Improve tower ground
PSerc
Transmitter
high voltage
PSerc
Transmitter
PSerc
Transmitter
Bond tower grounds
to building grounds
PSerc
Transmitter
Bond all grounds to service entrance
ground
PSerc
Transmitter
high voltage
PSerc
Transmitter
PSerc
Transmitter
Bond cable shield to tower
PSerc
Transmitter
high voltage
PSerc
Transmitter
Bond cable shield tobuilding steel
PSerc
Transmitter
Surge suppression:everywhere a conductor
entersthe facility:
secondary surge arrestors
PSerc
Transmitter
Surge suppression:everywhere a conductor
entersthe facility:
secondary surge arrestors
PSerc
Surge suppression:at sensitive equipment:transient voltage surge
suppressors(UL 1449 listed)
Transmitter
PSerc
Provide all possible safe paths to earth;
place surge suppression at the others
Transmitter
Bond cableshield to tower
Improvetower
ground
Bond all grounds to service entrance
building steel
SurgeSuppression
PSerc
Transmitter
Move service
entranceto ground
Or, even better, move all conductor
entrancesto one location at ground
level,through grounded copper
bulkhead.
PSerc
Lightning Protection: Customer Side Low Voltage Systems
Lightning will strike– rods or other devices will not stop all strikes
Lightning will flow to earth– insulation will not stop it
Keep it away from sensitive equipment– Provide safe paths to earth
– Bond all grounds
– Use arrestors and suppressors
» service entrance arrestors
» sensitive equipment suppressors
PSerc
pserc.org
APPA 2005 ENGINEERING & OPERATIONS
TECHNICAL CONFERENCEApril 18, 2005
