Micom P634 - Rapid (High-Set) Differential Protection

Along with this settable operate delay a starting signal was introduced for
logging purposes. DIFF: Starting is signaled if a valid differential protection trip
condition is determined, i.e. at least one measuring system has triggered (=
measures Idiff/IR within tripping area) and is not blocked from inrush or overflux
blocking, saturation discriminator or external binary input.
If differential protection is set to operate without operate delay, this starting
signal is raised together with the tripping signal.
If the current transformer supervision (CTS) function is used, the basic pick-up
sensitivity DIFF: Idiff> PSx can be increased to a value set at
DIFF: Idiff>(CTS) PSx.
1 2 3
1
0
I
diff
I
R
Fault current characteristic
for single side infeed
I
diff
>
I
R,m2
m
1
m
2
I
diff
>(CTS)
64Z9004A
Fig. 3-92: Changing the characteristic if CTS: Idiff>(CTS)active= Yes
3.21.6 Rapid (high-set) Differential Protection
Above the adjustable threshold DIFF: Idiff>> PSx of the differential current,
the P634 will trip without taking into account either the harmonic restraint or the
overfluxing stabilization. If the differential current exceeds the adjustable
threshold DIFF: Idiff>>> PSx, the restraining current and the saturation
discriminator are no longer taken into account either, that is the P634 will trip
regardless of the restraining value and the saturation discriminator.
P634
3 Operation
3-134 P634/EN M/R-42-A // P634‑311‑653