H.V. current cut-out circuit

Abstract

The invention relates to a current cut-out circuit for a high-voltage electric installation, a current source being located on an input side and an earth fault possibly occurring on its output side. The circuit is characterized in that between the input and the output, it includes for each phase, in series, a cut-out device (1) with a high arcing voltage, said device opening very rapidly, and a circuit-breaker (2) which opens rapidly and, shunt-connected between the input of the cut-out device with a high arcing voltage and earth, a resistance (4) for limiting an earthing current which passes via an automatic cut-out (3) with a very short closing time and a short opening time. Structure (5) is provided for performing the sequence of following operations in a time shorter than half a period: closing the automatic cut-out, opening the high arcing voltage device, opening the rapid-opening circuit-breaker and the automatic cut-out, and, when the current passes through zero, cutting out the high arcing voltage device, the rapid-opening circuit-breaker and the automatic cut-out. The invention applies to protecting switchgear.

Dependencies are inferred from the claim text.