PROCEDE ET DISPOSITIF DE MESURE ET DE CONTROLE DE L'ISOLEMENT ELECTRIQUE D'UN SYSTEME ACTIF

The invention envisages a method which consists in carrying out, over a sequence of four successive time steps, of the same duration equal to the period, or a multiple of the period, of the alternating leakage current likely to effect the system: a measurement of the common-mode voltage (VMC) between an electrical reference point of the system (A) and the surrounding earth (M), an injection of a direct current (I) of defined amplitude, in parallel with a measurement of the sum of the common-mode voltage and of the voltage, at the terminals of the leakage impedance (Zf), generated by the said injected current, a measurement of the difference between the sum of the voltages measured at step 2/ and the common-mode voltage measured at step 1/, and a resetting the measuring circuits of steps 1 and 2 to zero, so as to obtain, by step 3/, the value of the leakage impedance of the system, the injected current (I) being known. Application to measuring and monitoring the electrical insulation of an active system.