lightning protection Flashcards
Lightning will strike a static wire instead of a transmission phase because of the wire’s high resistance path to ground.
false
The three types of steel static wire that can be used to protect a transmission line include copperweld, ? , and ?
alumaweld / galvanized
A(n) ? lightning arrestor would be installed in a 230-kilovolt switching yard.
station
Protector tubes normally perform their function between transmission lines and the steel towers.
true
Of the two modern distribution lightning arrestors, the ? arrestor does not have gaps between the valves.
metal zinc oxide
The current resulting from a lightning strike is ?
dc
A surge (lightning) arrestor is a device that provides a path for a surge to discharge to ground. After the voltage surge is diverted to ground, the arrestor ?
chokes off the flow through current
A ? housing for a lightning arrestor reduces the damaging effect in case of a failure.
polymer
When dealing with lightning arrestors, the term MOV means ?
metal oxide varistors
If a transmission line has a history of too many damaging lightning strikes, the solution might be to improve the grounding of the ? .
static wire along the length of the line
A dead-front elbow arrestor would be used on a(n) ?
underground distribution
The static wire on a transmission line supported on wooden poles must be grounded at every structure to a ground rod.
false
A lightning strike may carry currents up to ?
200,000 amps
The heat produced from a lightning strike may be ? times hotter than the surface of the sun.
3
The maximum discharge voltage of a modern lightning arrestor should be ? less than the BIL of the equipment it is to protect.
20%
