DETERMINING THE ACTUAL REDUCTION FACTOR OF DISTRIBUTION CABLE LINES WITH APPLIED CROSS-BONDING

The considered problem appears as the consequence of the fact that many metal installations surrounding power lines in urban areas are situated under the surface of the ground and cannot be visually determined or verified. This paper presents the methodological version that enables solving the problem in the case of cable lines with cross-bonding, but it can also be applied with higher accuracy to cable lines with no applied cross-bonding than the existing one. It is based on the test measurement of currents appearing in two cable line phase conductors during a simulated ground fault in the supplied HV substation. By using the here-presented methodology it is possible to put the grounding problem of high-voltage distribution substations into realistic frameworks. Its application in practice shows that the actual conditions for solving this problem are much more favorable than was considered before

DETERMINATION OF ACTUAL REDUCTION FACTOR OF HV AND MV CABLE LINES PASSING THROUGH URBAN AND SUBURBAN AREAS

The paper presents the method for determination of ground fault current distribution in the cases when feeding cable lines are passing through urban and/or suburban areas, or when many relevant data are uncertain, or completely unknown. The problem appears as a consequence of the fact that many of surrounding urban installations are situated under the surface of the ground and cannot be visually determined or verified. On the basis of on site measurements, the developed method enables compensation of all deficiencies of the relevant data about metal installations involved with the fluctuating magnet field appearing along and around of a power line during an unbalanced fault. The presented analytical procedure is based on the fact that certain  measurable quantities cumulatively involve the inductive effects of all, known and unknown surrounding metal installations. The performed quantitative analysis points on at the significance of taking into account the existence of surrounding metal installations

COMPARATIVE ANALYSIS OF GROUNDING SYSTEMS FORMED BY FEEDERS IN ONE CASE WITH UNINSULATED AND IN THE OTHER CASE WITH INSULATED METALLIC SHEATH

ABSTRAC