METHOD FOR PREVENTION OF VOLTAGE COLLAPSE IN POWER SYSTEM Russian patent published in 2014 - IPC H02J3/24 

FIELD: electricity.

SUBSTANCE: method consists in measurement of voltage, active and reactive power on buses of the station, control of available alarms from a stationary automatics of the generator "imitation of current overload of a rotor" and if they are available from all generators connected to buses of the station, then trip of load of the controlled power district is performed with accurate determination of unloading volume, which is calculated as per the following formula: $$\Delta P_1=\frac{B-\sqrt{B^2-AC}}{A},$$ where A, B, C - design factors determined based on measurement of values of active power, reactive power and voltage on buses of the station.

EFFECT: elimination of a deficit of reactive power in the power district and prevention of avalanching voltage reduction.