DEVICE FOR PROTECTING A THREE-PHASE ELECTRICAL INSTALLATION FROM OPEN-PHASE OPERATION Russian patent published in 2022 - IPC H02H7/09 

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of electrical engineering for the protection of a three-phase electrical installation, mainly an arc furnace transformer. The device contains a three-phase circuit breaker, a circuit breaker control unit and emergency mode sensors. According to the invention, the three emergency mode sensors consist of: a current transformer, the primary winding of which is included in the phase of the electrical installation, while the secondary winding is connected in parallel with the primary winding of the zero-sequence current transformer. The secondary winding of the zero-sequence current transformer is connected to a diode rectifier. A load resistor and a low-pass filter are connected in parallel to the diode rectifier. The output of the low-pass filter is connected to a parametric voltage regulator.

EFFECT: increasing the reliability of protection by increasing the reliability of identification of the open-phase mode.

1 cl, 3 dwg