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 electrical power supply network in which at the ends (11a, 11b) of the line (11) with inductive current transformers (14a, 14b) current signals are generated, which at one end (11a, 11b) are proportional to flowing current, current measuring values are formed for each end (11a, 11b) with measuring devices from the respective current signal, which indicate a profile of the current flowing at the respective end (11a, 11b) from the current measured values for each At the end of each charge value is determined, the charge values of all the ends (11a, 11b) are summed in the correct sign to form a charge sum, and an error signal indicating an internal fault on the line (11) is generated if the charge sum exceeds a charge threshold.;In order to be able to operate a line differential protection in a simple manner as reliably as possible even with current transformer saturation, it is proposed that a charge estimation value be determined with the appropriate transducer saturation with the corresponding measuring device, and the charge estimate used to form the charge sum.;The invention also relates to a corresponding differential protection device and a differential protection system.