help for the clearance between the shield wire and PHASE conductor in substation
help for the clearance between the shield wire and PHASE conductor in substation
(OP)
In a substation design, we choose shield wire for protection against lightning.
How to determine the clearance for the shield wire and the phase conductor in case of lightning couter attack?
Are there any IEC standards regarding to this issue?
P.S. if the distance is too short ,there may be an lightning counter-attack over-voltage on the phase conductor.But how about the distance?
How to determine the clearance for the shield wire and the phase conductor in case of lightning couter attack?
Are there any IEC standards regarding to this issue?
P.S. if the distance is too short ,there may be an lightning counter-attack over-voltage on the phase conductor.But how about the distance?






RE: help for the clearance between the shield wire and PHASE conductor in substation
Good luck,
Dave
RE: help for the clearance between the shield wire and PHASE conductor in substation
I want to check the air clearance between the shield wire and the phase conductor!Thanks!
RE: help for the clearance between the shield wire and PHASE conductor in substation
But I have never found that to be the design-constraining issue.
Typically, I have found that desired height of my shield wires or 'rods' to provide effective lightning coverage provides considerably more clearance than that 'minimum' I mentioned previously.
RE: help for the clearance between the shield wire and PHASE conductor in substation
RE: help for the clearance between the shield wire and PHASE conductor in substation
In my 45+ years of working in, designing or installing substations, never have I ran across this problem. The shield wire is always keep at least the minimum clearance for highest voltage phase wire to ground. Most of the time I like the clearance higher, due to maintenance issues using manlifts, cranes, ect. Sometimes you do not have that luxury of going up higher.
Hope this helps,
Dave
RE: help for the clearance between the shield wire and PHASE conductor in substation
RE: help for the clearance between the shield wire and PHASE conductor in substation
RE: help for the clearance between the shield wire and PHASE conductor in substation
Lightning is not 'hunting' for your phase wire.
It is seeking a discharge path between the air and ground.
If a given stroke of lightning hits a well-grounded shield wire, in my 25 years of experience it will not jump ANOTHER large air gap to damage your equipment.
Your shield wire should represent a fraction of an Ohm resistance to earth, compared to the megaOhms or gigaOhms of the several feet/meters of the air gap.
The separation I was quoting was to provide your energized equipment isolation from GROUND, including that of the grounded shield wire.