ASYNCHRONOUS MODE DETECTION METHOD Russian patent published in 2003 - IPC

FIELD: electrical engineering; emergency automatic control of power systems. SUBSTANCE: method involves use of current and voltage measurement results obtained on one end of power transmission line to determine signs of relative angle between voltages across ends of line section under protection and signs of its first and second time derivative and to find reactance X_MIN from point of measurement to minimal-voltage point, and also sign of active-power time derivative conveyed over power transmission line; initial moment of asynchronous mode is recorded if minimal-voltage point resides within power transmission line section under protection, signs of relative angle and of its first and second derivatives coincide, and sign of active-power time derivative is reverse to them; checking for minimal-voltage point on line under protection boils down to checking 0<X_MIN<X_l condition, where X_l is reactance of power transmission line. EFFECT: enhanced selectivity in detecting asynchronous mode in modern power systems. 2 dwg