ABB RELION 630 Series Technical Manual page 275

1MRS757256 F
PML630/Compact Load-Shedding Solution
Technical Manual
Based on the Ov Curr Trg interval setting, overcurrent operating statuses of the power
sources can be configured to re-trigger the slow load trigger.
If the Ov Curr Trg interval setting is zero, slow load-shedding trigger remains active
until the overcurrent operating status is activated.
If the overcurrent status is activated, slow load-shedding trigger is calculated at an
interval of Ov Curr Trg interval setting.
load-shedding trigger if OC_ORP_SRC1 gets activated for power source 1.
1
OC_OPR_SRC1
0
1
SLS_TRG_SRC1
0
GUID-2C90BD8E-EF2B-4375-8814-FF68EF4292FD V1 EN
Figure 147: Profile of slow load trigger w.r.t Ov Curr Trg interval setting
Here, t = Set value of Ov Curr Trg interval setting
Figure shows the calculation of slow load-shedding trigger and slow load-shedding
enable signals for power source 1.
OC_OPR_SRC1
MAX_DMD_SRC1
EXT_SLT_SRC1
SLS_TRG_INH
SLS_INH_SRC1
GUID-A787A72E-B271-4CA2-BBE9-3AFD6D4027CA V1 EN
Figure 148: Logic for calculation of slow load-shedding trigger and slow load-
shedding enable signals for power source 1
The logic is identical for all the power sources.
The module also calculates the slow load-shedding start, fast load-shedding trigger
and busbar number signals for all the power sources.
If the slow load-shedding start signal is activated for any power source (power source
1...power source 8), slow load-shed start SLS_START is activated, provided the
SLS_TRG_INH input is FALSE.
Power management functions
Figure 147
t
Time( in seconds)
OR
AND
AND
Section 7
shows the calculation of slow
Slow load shed trigger
(To Busbar logic module)
Slow load shed enable
(To Busbar logic module)
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