Corona (electric field) strength 1

[Power0020]

Clause 4.3.3 in ABB Switchgear Manual recommends designing the HV conductors below 19 kV/cm, and marginally at 21 kV/cm (I believe this is too high!), I am currently working on 400 kV station with a requirement of 16.5 kV/cm, this needs a quad conductor configuration.

Does 16.5 kV/cm limit the corona hissing? any difference if designed at 19 kv/cm?

Thanks

 

[7anoter4]

According IEEE Std 605-1998 IEEE Guide for Design of Substation Rigid-Bus Structures Annex D
Figure D.1 Allowable surface voltage gradient for equal radio-influence generation under standard conditions versus bus diameter
the allowable surface voltage gradient Eo depends [for the standard conditions of atmospheric pressure and temperature] on conductor diameter –for about 1 inch bus diameter permissible is 19 kV/cm and for 15 inches diameter is only 9 kV/cm.

 

[Power0020]

Should this work for OH conductors?

There will be some roughness to add up into the Eo equation, howeover, it might be misleading with the bus diameter if bundled conductors are used to lower the surface gradient (the bigger the bus, the lower the allowable surface gradient).

 

[7anoter4]

I think EPRI AC Transmission Line Reference Book—200 kV and Above, Third Edition
ch. 8.4.1 may be interesting for overhead transmission lines.