Difference between the partial self inductance at DC and at HF

The difference between the DC and the HF partial self inductance of a single conductor is determined by considering the DC and the HF inductance separately for a finite, large length. Both inductances contain the same logarithm(length) singularity, which disappears in their difference. It involves the logarithm of the ratio of the equivalent radius and the geometrical mean distance. We have applied this to some common conductor cross sections: circle, ellipse, rectangle and diamond and to the limit of zero thickness of these cross sections. In the latter case a general expression is derived.