TOTAL SECTIONALISING PROTECTION DEVICE FOR THREE-PHASE NETWORK FROM SINGLE PHASE-TO-GROUND FAULTS

摘要

FIELD: electricity.;SUBSTANCE: method is implemented due to introduction of an auxiliary computation module to calculate an integral average value for variable component of instantaneous power surge in the three-phase line within the limited preset interval time average Θ_set1 ms and to determine this surge sign simultaneously in case of intermittent fault and of an auxiliary starting element of the protection device made as a timer setting the countdown start point and duration of the power surge interval time average; in the actuating device of the protection there is an auxiliary logic maxi-selector/analyser to identify the biggest value of the instantaneous power surge in the line and to determine this surge sign simultaneously in regards to similar surges in other lines of the network. For each protected line a relay actuator based on logic "OR" function is used in order to ensure control compatibility both for persistent and intermittent faults.;EFFECT: providing higher selectivity and reliability of damaged line detection in the network.;1 dwg