METHOD FOR PROTECTING HIGH-VOLTAGE LINES Russian patent published in 1998 - IPC

FIELD: electrical engineering. SUBSTANCE: method involves voltage measurements, its analog-to-digital conversion, detection of emergency situation by comparing measured and converted variables with desired values; in addition, it includes current measurement and its analog-to-digital conversion with emergency situation detected by comparing results of measurement of voltage, current, and angle between them made in two steps; during first step, measured and converted phase values of variables are compared with each other and with rated values by magnitude and angle, and deviations of measurement results from rated values are determined; during second step, kind of emergency situation is determined by amount of shift between voltage and current vectors, and line is disconnected with time delay complying with emergency conditions considering conditions of supply mains. EFFECT: facilitated detection of overvoltage or short-circuit of any kind in line; improved conditions for matching protective gear. 11 dwg