Areva MiCOM P441 - P44 X;En AD;E44

P44x/EN AD/E44 Update Documentation
Page 32/82 MiCOM P441, P442 & P444
That flat delta criteria (Enabled by S1) will improve the detection of a 3 Phase fault
during a power swing (in case of faulty current lower than the Imax line threshold
settable in S1) – 100ms are requested for unblocking the logic.
With the exaggerated delta current (activated all the time in the internal logic) the
phase selection has been improved in case of unblocking logic applied with a fault
detected during a power swing. Regarding the presence of negative current or zero
sequence current , the exaggerated deltas current detection are calculated on the
phase-phase loop or ground phase loop.
2.13.5 Out Of Step (OOS) - (New section)
A new feature has been integrated since C1.0, which can detect the out of step (OOS)
conditions.
• How MiCOM Detect the out of step ? :
When the criteria for power swing detection are met, and when out of step tripping is
selected, then the distance protection with all of its stages is blocked – in order to prevent
tripping by the distance protection (The relay can operate normally for any fault occurring
during a power swing as there are different criteria which can be used by monitoring current
& delta current).
When the locus of the 3 single phase loops leave the power swing polygon, the sign of R is
checked. If the R component still has the same sign as at the point of entry, then the power
swing is detected and managed in the internal logic as a stable swing.
Otherwise the locus of the 3 single phase loops have passed through the polygon (indicating
loss of synchronism) and the sign of R is different from the point of entry ; then an out of step
is detected.
In the both cases the MiCOM P440 will provide a monitoring of the number of cycles and
control if the setting from S1 has been reached. In that case a trip order is performed by the
relay.
X lim
-R lim
R lim
-X lim
∆ R
R
X
∆ X
Z4
Z3
Stable swing
Out Of Step
+R
+R
+R
-R
Zone A
Zone C
Zone B