BROADBAND CURRENT TRANSFORMER WITH VARIABLE SENSITIVITY DEPENDING ON MEASURED SIGNAL FREQUENCY

摘要

The invention relates to a current transformer operating in broadband, with variable sensitivity depending on the measured current frequency. According to the invention, the transformer comprises a magnetic circuit (1), a secondary winding (2), an integrated loading resistance (3) and an electrostatic screen used to reduce the capacitive coupling with the circuit wherein the current is measured, represented by the primary winding (4), the transformer supplementarily comprising a dipolar circuit (6) mounted in parallel with the loading resistance (3) at the transformer voltage output, with the role of increasing the l/f ratio at low frequencies, circuit made so as to represent an impedance Z(f) depending on the frequency of the current to be measured and dimensioned so that, on the one hand, it has a resistive behaviour within a preset low frequency range, and, on the other hand, it does not interfere at high frequencies within the transformer measuring range.