Motor Negative-Sequence Overcurrent Protection Mnsptoc - ABB RELION 630 Series Applications Manual

Section 3
REM630 variants
3.2.6.7
34
operates when the negative-sequence current exceeds the corresponding set limits.
Phase reversal protection is blocked when current circuit supervision detects a failure.
Operate signal is used to trigger the disturbance recorder.

Motor negative-sequence overcurrent protection MNSPTOC

Two instances of negative-sequence overcurrent detection are provided for protection
against single-phasing, unbalance load or unsymmetrical voltage. The set of three
phase currents, I3P, is connected to the inputs.
The function operates in two modes, the definite time mode (DT) and the inverse
definite minimum time (IDMT) mode, for which two instances of the function block
are used. The negative-sequence overcurrent protection is blocked in case of current
circuit supervision failure is activated.
The common operate and start signal from the both MNSPTOC functions are
connected to an OR-gate to form a combined negative-sequence overcurrent operate
and start signal which is used to provide a LED indication on the LHMI. Also a
separate start and operate signal from the both MNSPTOC functions is connected to
the disturbance recorder.
GUID-76CCD7FC-6435-476A-93EB-35411E87FC96 V2 EN
Figure 11: Motor negative-sequence overcurrent protection
1MRS756785 G
REM630
Application Manual