Electrical energy meter comprising at least one inductive type electricity measuring sensor, and associated sensor

摘要

The invention relates to an electrical energy meter comprising at least one sensor (1; 1') for measuring inductive type electric current with a primary circuit (3; 3') traversed by an alternating current (I) to be measured, a secondary circuit (40) magnetically coupled in air with the primary circuit (3; 3'), a shielding element (6) of the unit formed by the primary circuit (3; 3') and the secondary circuit (40), and means (7, 10,17,26, 90) for measuring the saturation state of the shielding element (6), comprising in accordance to the invention a winding forming a tertiary circuit (7; 7') between the secondary circuit (40) and the shielding element (6), through which flows an injection current (I1NJ) with an alternating frequency (fi), fixed and different from the fundamental and harmonic frequencies of the current (I) to be measured; generating means (10, 90) for the injection current (IINJ), and means (7, 10,17,26, 90) of measuring a representative value of the mutual inductance (M2) between the secondary and tertiary circuits, and a comparison means (25) of the measured value with at least one calibrating value (M2max), a state of partial or total saturation of the shielding element which can be deducted when the measured value is less than the calibration value.