Strung & Disc Type Insulator

[Linspire]

Hi,


I would like to know what is the corona inception voltage for Strung & Disc Type Insulator on 275kV Substation ?
The creepage distance is 7500mm ( 300 V x 21 mm / kV ), and the tension sustainable is 120 kN.

Does 1.1 times Phase to Earth Voltage is minimum/maximum value of corona inception voltage ?

I'm first time know these term. Kindly assist me.


Regards,
Linspire

 

[ghostbuster7]

Corona inception voltage is a direct function related to the electrical field gradient present at the site.There is negative corona(buzz) that first appears and later at a higher voltage there is positive corona(large crackling sound).

 

[Linspire]

So what's the value for corona inception voltage of disc & strung insulator on 275 kV Substation design ?

 

[ghostbuster7]

You do not understand.There is no real answer until the exact specifics are all known.

I can make this string break into corona at 200 kv. with the insulator string located close to the ground or at 400 kv. with the insulator string at 40-50 feet above ground.

It all depends on the electrical gradient created between this string and your specific ground plane configuration.