Inductive Interaction of an HV or EHV Distribution Cable Line and Surrounding Metal Installations

The presented paper introduces a significant simplification into the application procedure of the methodology that enables the analysis of electric circuits spontaneously formed by HV and EHV distribution cable lines. The pulsating magnetic field created by currents in these lines induces voltages and currents in all surrounding metal installations typical of urban environments. Each of the induced currents creates its own magnetic field which acts in such a way that reduces all other induced currents including currents in the inducing cable line. The problem arises because these installations are mainly situated under the surface of the ground, and because of that, their constructive characteristics and spatial positions are usually uncertain or completely unknown. Because of that, the problem of determining the effects of the inductive interaction of a certain cable line and these installations was for a long time considered practically unsolvable. Only recently was developed a methodology that enables its solving based on the specially defined test measurement and an equivalent cable sheath introduced in the developed analytical procedure. This paper shows that the methodology is applicable for determining any of the inductive interaction effects by using the results of only one test measurement, or based on the simultaneous measurements of voltages and currents at the ends of an HV or EHV cable line.