ZERO SEQUENCE CURRENT BASED DIFFERENTIAL PROTECTION OF A TRANSMISSION LINE

摘要

There is provided mechanisms for zero sequence differential protection of a transmission line of a power system. An arrangement comprises a zero sequence differential protection unit configured for, using current measurements of each phase A, B, C of the transmission line, internal fault detection of the transmission line. The arrangement comprises a phase selection unit configured for, using a comparison of differential values of the current measures for each phase, determination of whether any of the phases A, B, C of the transmission line is faulty or not. A trip is caused by the zero sequence differential protection unit when an internal fault is detected by the zero sequence differential protection unit, and the trip starts all the phases A, B, C for the phase selection unit to finalize the trip for said any faulty phase.