The invention relates to a method for insulating a first conductor (21) of a first continuous high voltage power drive line connected to at least one link node in question comprising at least three distinct links each associated with at least one cut-off device, characterised in that the method comprises, according to an item of information on the criticality of the fault relative to the link node in question: - either, for a targeted opening operation, moving the electrical cut-off device (28.11) from its closed state to its open state, while maintaining each of the second (28.12, 29.1b) and the third (28.13; 18.1; 29.1) electrical cut-off devices in their closed state; - or, to fully open the node in question, interrupting all the power flows in all of the links of the node.