DIFFERENTIAL PROTECTION METHOD, DIFFERENTIAL PROTECTION DEVICE AND DIFFERENTIAL PROTECTION SYSTEM

摘要

The invention relates to a differential protection method for monitoring a line (11) of an energy supply network, in which current vector measured values are recorded at the ends (11a, 11b) of the line (11) and transmitted to an evaluation device, by means of which a differential current value is formed with current vector measured values assigned to one another over time , with time offset information indicating the time offset between local timers (CLK) of the measuring devices being used for the temporal assignment of the current vector measured values recorded at different ends (11a, 11b), and an error signal indicating an error with regard to the line (11) being generated when the differential current value exceeds a specified threshold value. In order to further increase the reliability of the time synchronization of the internal timers in a differential protection system, it is proposed that a quotient of the current vector measured values assigned to one another over time, forming an asymmetry Rie size is formed, the asymmetry size being used to check a delay time difference of telegrams transmitted via the communication link (16), which results from different transmission times depending on the direction. The invention also relates to a corresponding differential protection device and a differential protection system.