DEVICE FOR INTELLIGENT CURRENT PROTECTION OF CABLE LINES AGAINST SINGLE-PHASE GROUND FAULTS Russian patent published in 2024 - IPC H02H3/16 

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering and can be used for relay protection of cable lines with voltage of 6-35 kV, operating with isolated or resistive-earthed neutral in single-phase ground faults. Current sensors in cable shields are introduced into intelligent current protection against single-phase ground faults. Application of these sensors makes it possible to determine occurrence of currents in screens of single-phase cables at occurrence of single-phase faults to ground. Values measured by current sensors are supplied to the first input of the relay element of the protection unit with the set actuation setting. Setting current value is automatically corrected depending on the operating conditions of the protected cable line, i.e. adaptive correction of this current is performed. To this end, the first input of this unit receives a signal on the value of the protection setting current, the second input receives a signal on the value of the earth fault incompleteness value calculated in the module from the voltage values at the output of the voltage measuring transformer, the third input receives a signal on the value of the short-circuit resistance from the output of the second microcontroller. This device allows to carry out operation of protection on cable lines in electric networks made as three-phase groups containing three single-phase cables, which include current-conducting shields located above insulation of current-carrying conductor and grounded at least at one end of cable line.

EFFECT: providing operation of intelligent current protection against single-phase ground faults on cable lines consisting of three single-phase cables in networks with insulated and resistive-earthed neutral.

1 cl, 1 dwg