Micom P631, Technical Manual

Page: 173 / 638

1 2 3
1
0
I
diff
I
R
Load line
for single side infeed
I
diff
>
I
R,m2
m
1
m
2
I
diff
>(CTS)
64Z6030A_EN
Fig. 3-83: 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 P631 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 P631 will trip
regardless of the restraining value and the saturation discriminator.
62Z5071A
DIFF:
Id,1
303 303
DIFF:
IR,1
303 305
DIFF:
Id,2
303 304
DIFF:
IR,2
303 306
DIFF:
Id,3
303 307
DIFF:
IR,3
303 308
Id,1 = f(I̲s,1,z)
Id,2 = f(I̲s,2,z)
IR,1 = f(I̲s,1,z)
IR,2 = f(I̲s,2,z)
Id,3 = f(I̲s,3,z)
IR,3 = f(I̲s,3,z)
I̲s,1,a
I̲s,1,b
I̲s,2,a
I̲s,2,b
I̲s,3,a
I̲s,3,b
End a, b z:
Fig. 3-84: Forming the differential and restraining currents for the three measuring systems
3 Operation
P631
P631/EN M/R-11-C // P631-310-650 3-117