Phase Reversal Protection - ABB REM 610 Technical Reference Manual

1MRS 752263-MUM
4.1.4.8.
Motor protection Relay
Technical Reference Manual
The figure below illustrates the inverse-time curves of stage I
K=5 K=20 K=40 K=100
I /I
2 n
1
0.1
1
Fig. 4.1.4.7.-1 Inverse-time curves of stage I

Phase reversal protection

The phase reversal protection is based on the calculated negative-phase-sequence
current and detects too high NPS current values during motor start up, caused by
incorrectly connected phases, which in turn will cause the motor to rotate in the
opposite direction.
When the calculated NPS current value exceeds 75 per cent of the maximum phase
current value, the phase reversal stage (REV) will generate a trip signal after a fixed
200 ms' operate time.
The stage will be reset in 200 ms after the calculated NPS current value has fallen
below 75 per cent of the maximum phase current value.
The phase reversal stage can be set out of operation in SGF3.
Note!
The unbalance stage will be blocked during the tripping of the phase reversal stage.
10 100
>
2
REM 610
>.
2
I > = 0.5 x I
2
I > = 0.2 x I
2
I > = 0.1 x I
2
1000 10000
n
n
n
t/s
100000
33