Functions
2.14 Differential Protection and Its Protected Objects
SIPROTEC, 7UM62, Manual
C53000-G1176-C149-7, Release date 03.2010
110
For special cases, the trip command can be delayed.
The following figure shows a simplified diagram of the tripping logic.
A dropout is detected when, during 2 cycles, pick-up is no longer recognized in the differential value, i.e. the
differential current has fallen below 70 % of the set value, and the other pickup conditions are no longer fulfilled
either.
If a trip command was never initiated, the fault is considered ended on dropout.
If a trip command was initiated, it is maintained for the minimum command duration set in the general device
data for all protection functions (see also Section P.System Data 1).
Note
The special features of the differential protection for individual protected objects are described in separate
chapters.