ZERO SEQUENCE CURRENT FILTER BASED ON TRANSFORMER DEVICE WITH SHORT-CIRCUITED WINDING Russian patent published in 2025 - IPC G01R29/16 H02H3/16 H01F30/14 H02M5/14 

FIELD: measuring; electricity.

SUBSTANCE: invention relates to measuring and converting equipment, and more precisely to measuring transformers, and can be used as an input element of protection devices and automation of power supply systems. Device enables to obtain rectified voltage at the filter output, the value of which is proportional to zero-sequence current in a three-phase AC network. Multiphase rectification allows reducing output voltage ripple and selecting zero sequence without using smoothing output capacitors increasing system time constant.

EFFECT: increased accuracy of relay protection actuation in asymmetric emergency due to connection to three-phase system of voltages of three identical for each phase transformer devices with short-circuited windings with primary and secondary windings located on them and connecting in a special way the secondary windings of these devices to the multiphase rectifiers, as well as the formation of direct voltage, the value of which is proportional to the zero sequence current in the three-phase alternating current network.

1 cl, 1 dwg