The threshold value of, r1/ r2 so that partial breakdown can
be avoided in a cylindrical geometry. Figure 6 shows the
variation of g using coaxial cylinder geometry for various
inner conductor diameters with a fixed outer conductor
diameter and constant voltage of 11 kV between inner and
outer cylinders.
When r1/r2 is equal to or less than 0.368 an increase in r1
increases the electrical field. If r1/r2 > 0.368, then corona
forms [20]. Two primary conductor diameters, namely dl and
dh, are chosen to study the effect of the primary conductor
diameter on the frequency response of the PFCT. Primary
conductor diameter dl lies below the threshold and dh lies
above the threshold in such a way that the breakdown strength
of air is not reached at the specified voltage level.
From the inner radius of PFCT, r2 = 37.5 mm, two primary
conductor radii namely (rl = 13.8mm, dl=27.6mm) and (rh =
22.9mm, dh =45.8mm) are chosen to study the effect of the
primary conductor diameter on the frequency response of the
PFCT obtained from Figure 6.