foerfarande foer selektiv detektering av that defekt motstaond i that distributionsnet foer elektrisk energi och i anordning foer dess verkstaellande

摘要

Method for the selective detection of a resistive defect on a departure line of an electrical power-distribution network comprising an arrival line (12) powered by a transformer (11) and several departure lines (1-8) each departure line being fitted with a homopolar current detector (9), characterised in that the homopolar current (i1-i8; 1'1-i'8) of each departure (1-8) is continuously measured in amplitude and in phase shift with respect to a reference magnitude, in that the vector sum of the set of homopolar currents of the departure lines is calculated, and the phase-shift of each homopolar current with respect to the phase-shift of the said vector sum is monitored, the presence of a defect being detected when the said phase-shift of a homopolar current exceeds a predetermined negative threshold. IMAGE