| 摘要 |
FIELD: electrical engineering. ^ SUBSTANCE: invention relates to power transmission line protection circuits that perform automatic cutting off followed by repeated cutting it on and respond to difference in currents, wherein voltage or current values are compared at various points of different wires of one and the same circuit. For example, compared are currents in lead and return conductors. Proposed method comprises measuring current magnitude and direction at power line ends. Signal proportional to current difference in lead and return conductors is generated. Signal proportional to current difference variation rate in lead and return conductors is generated. Aforesaid signal is compared to threshold signal. Signal to switch off power line is generated if aforesaid signal exceeds threshold signal. Data from other systems is accumulated and the signal to switch off power line is generated on reception of signals from other systems. In compliance with the other version, proposed device comprises the main switch, first and second current pickups, subtraction circuit, current difference variation rate measuring circuit, threshold device, first and second electronic switches, OR-element and control and display device. ^ EFFECT: expanded performances. ^ 2 cl, 1 dwg |
