ABB RELION 630 Series Technical Manual page 298

Section 7
Power management functions
292
If multiple load-shed triggers are activated at the same time, the cause of load-shed
corresponds to the lowest preference number.
If priority-based manual load-shed action is performed along with any
other trigger getting activated at the same instance, the cause of load-
shed is manual load-shed provided manual load-shed priority is
greater than the load-shed priority calculated due to any other trigger
for the subnetwork z.
If slow load-shed trigger is active along with any other trigger at the
same instance, the cause of load-shed is slow load-shed provided the
load-shed priority calculated due to OV_LOAD
load-shed priority calculated due to LS_POWER
The module calculates the must-shedding status MUST_SHD_STS
reserve status SP_RESV_STS
ACT_SHD_LOD –
Z
|MUST_SHD_LOD | < 0
Z
SHD_PRIO_RC1 = 19
Z
LS_BLOCK<z>
LS_OPR_STS
Z
"E xtended load s hed" or
"F as t load s hed"
=> 0
POWER_BAL
Z
GUID-60FD150E-9423-42A5-86CE-04E43DE8C3B4 V1 EN
Figure 157: Must-shedding status and spinning reserve status calculation
If MUST_SHD_STS is active, extended must-shedding power MUST_SHD_POW
z
is the difference of the ⃒MUST_SHD_LOD
If SP_RESV_STS is active, the extended spinning reserve power SP_RESV_POW
z
is same as the power balance POWER_BAL
The module reports the MUST_SHD_STS
and SP_RESV_POW to the Peer load-shed logic module.
z
The reset inputs, that is, RESET_SN1, RESET_SN2, RESET_SN3 and
RESET_SN4, are provided to reset the load-shed data in respective subnetwork. For
example, if RESET_SN1 or RESET input is active, the power balance, effective load-
shedding power, actual load-shedding, load-shedding operation and recorded
priorities are reset.
for adjacent electrical area as shown in
z
&
tOff=50ms
&
t
&
⃒ and ACT_SHD_LOD
z
.
z
, SP_RESV_STS
z
PML630/Compact Load-Shedding Solution
1MRS757256 F
is greater than the
z
.
z
and spinning
z
Figure 157.
MUST_SHD_STS
Z
SP_RESV_STS
&
Z
.
z
, MUST_SHD_POW
z z
Technical Manual
z
z