SYNCHRONISATION METHOD FOR DIFFERENTIAL CURRENT PROTECTION Russian patent published in 2014 - IPC H02H7/26 

FIELD: electricity.

SUBSTANCE: method involves the following stages: point is chosen in a transmission line protected by differential current protection; current and voltage is measured on each of the poles of the transmission line; compensating voltage is calculated at the chosen point according to the measured current and voltage on each of the poles; a synchronisation error is detected and calculated by comparing compensating voltages. Current and voltage on each of the poles are measured before or after a fault occurs, and they can be measured in the form of vector random values, phase values or sequence values. The point can be chosen in any place of the transmission line, preferably in the middle or on ends of the transmission line, or at the point of a T-shaped connection of multipole transmission lines. In addition, the synchronisation method involves a detection stage of a cause of a synchronisation error: strong change in the parameter of the line or symmetric switching of the channel; detection is performed by calculation of a rate of change of difference of a phase angle or a wave shift of the above compensating voltage.

EFFECT: improving reliability.

9 cl, 22 dwg