Micom P631 - Page 546

Phase sequence A–B–C
●
φ
AB,z
= φ
BC,z
= φ
CA,z
= 120°
Phase sequence A–C–B
●
φ
AB,z
= φ
BC,z
= φ
CA,z
= −120°
This is not influenced by the set value of the function parameter for the phase
sequence.
The phase angle between the phase currents of two transformer ends for a
particular phase is a function of the vector group of the transformer. This phase
angle should be displayed as follows:
Vector group
0 = 12 φ
x,A–z
= ±180°
1 φ
x,A–z
= −150°
2 φ
x,A–z
= −120°
3 φ
x,A–z
= −90°
4 φ
x,A–z
= −60°
5 φ
x,A–z
= −30°
6 φ
x,A–z
= 0°
7 φ
x,A–z
= 30°
8 φ
x,A–z
= 60°
9 φ
x,A–z
= 90°
10 φ
x,A–z
= 120°
11 φ
x,A–z
= 150°
This is not influenced by the set value of the function parameter for the phase
sequence. Changing the setting for the connection scheme of an involved series
transformer, on the other hand, will change the measured operating data value
by ±180°.
10.2.5.2 Checking Ground Differential Protection
The current I to which the P631 responds for single-side feed, neutral-point side,
is calculated as follows:
I ≥
I
diff >
⋅ I
nom
k
am,z
●
z: transformer end (a, b)
●
I
diff>
: set operate value
●
I
nom
: nominal current of the P631
●
k
am,z
: amplitude-matching factor of transformer end a, b
There will be no trip for single-side, single-pole, phase-side feed.
P631
10 Commissioning
10-8 P631/EN M/R-11-C // P631-310-650