Differential protection method, differential protection device and differential protection system

摘要

In a differential protection method for monitoring a line of a power grid, current indicator measured values are measured at the ends of the line and are transmitted to an evaluation device. A differential current value is formed with current indicator measured values temporally allocated to one another. The time delay between local timers of the measuring devices is used for the temporal allocation of the current indicator measured values measured at different ends. A fault signal indicating a fault affecting the line is generated if the differential current value exceeds a predefined threshold value. A check is carried out using electrical measured quantities temporally allocated to one another and a line-specific parameter to determine whether the time delay information indicates the actual time delay between the respective local timers. A time error signal is generated if erroneous time delay information is detected.