ABB RELION 630 Series Technical Manual page 229

1MRS757256 F
PML630/Compact Load-Shedding Solution
Technical Manual
The calculated OC_TIME output reflects the timings when the IED
receives the input currents. Hence, the actual time of the trigger
matches the OC_TIME output only if the current inputs remain the
same throughout the duration of the overload. If the input current
changes subsequently, the OC_TIME output time also changes
correspondingly.
The output ELAPSE_TIME is time elapse after OC_STR is TRUE.
The outputs OC_TIME and ELAPSE_TIME are reported for the monitoring view.
Once the output OC_STR is FALSE, the outputs OC_TIME and ELAPSE_TIME are
reset.
The module can be reset by the input RESET_OC. If the input RESET_OC is TRUE,
the outputs OC_OPR, OC_TIME and ELAPSE_TIME are reset.
The different ANSI/IEC curve type operating time characteristic depends on the
Curve parameter A, Curve parameter B, Curve parameter C, Curve parameter D,
Curve parameter E, Time multiplier, Operating curve type, Operate delay time and
Minimum operate time settings. Similarly, the reset curve functionality depends on the
Type of reset curve and Reset delay time settings.
In this function block, some of the settings are set in per unit (pu). These per unit values
are relational to the certain base values. The PML630 IED supports alternative base
value groups in the Base value Sel phase setting, for example "Phase Grp 1", "Phase
Grp 2" and "Phase Grp 3".
The output INVAL_CRV is TRUE if the Operating curve type setting is selected
"Programmable" and the curve parameter values are invalid, else the output
INVAL_CRV is FALSE.
For more information on overcurrent start and operate based on
different Timer characteristics and relevant inputs, see the PHLPTOC
function of the three-phase non-directional overcurrent protection
PHxPTOC in the 630 series technical manual.
For a detailed description of the definite time characteristics and
current based inverse definite minimum time (IDMT) characteristics,
see the general function block features section in this manual.
The overcurrent settings in PML630 must be coordinated carefully
with the IED of the power source.
The external slow load-shedding trigger is also initiated if the input EXT_OC_SLST
changes from FALSE to TRUE.
Power management functions
Section 7
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