corona factor F

[mersin33]

Could anybody help me with the meaning and/or typical value of a "corona factor F" in the following equation for fair weather corona loss:

P=(0.000021xfxV^2xF) / ((log(2xs/d))^2

where;

P corona loss in kW/km
f frequency in Hz
V line to gnd voltage in kV
s spacing between conductors cm
d conductor diameter in cm
F corona factor determined by test

I have gone through many references but none of them refers to a typical F value for a double cct 230 kV transmission line.

Can anybody help me with this?

Thanks in advance

 

[RAMConsult]

The clue here is that 'F' is determined by test; i.e., it is a function of multiple factors which can vary widely and whose combinations are too varied to determine a typical value. Some of these factors include conductor: material; construction; number, pitch, and diameter of strands; intra-phase spacing; weather; etc. There is a discussion of corona and aerial lines on pages 56-63 of the "Electrical Transmission and Distribution Reference Book" by the Central Station Engineers of the Westinghouse Electrical Company.

 

[jbartos]

Suggestion: First, it is necessary to calculate whether or not the corona is present. Then, the corona factor can be established under certain assumptions, e.g. air density factor and dielectric strength of air.
Reference:
C.L. Wadhwa "Electrical Power Systems," 2nd Ed., John Wiley & Sons. Chapter 6 Corona on page 135

 

[mersin33]

ramconsult and jbartos,

thank you for your comments. I have the westinghouse book, however it does not refer to an F factor in the fomula I mentioned. I do not have the wadhwa book.

jbartos,

are you suggesting that there will be no corona power loss if disruptive electric field is not achieved? I calculated the min disruptive voltage for canary for given tower configuration and it is above 230kV, which is the line voltage.

thank you

saltan