ABB RELION 630 Series Technical Manual page 297

1MRS757256 F
PML630/Compact Load-Shedding Solution
Technical Manual
Equation 18 shows the calculation of cumulative sheddable load power
p
for each priority p in the subnetwork z.
CUM_LOD_PR
z
p
=
CUM LOD PR _ _ SHD POW
z
GUID-8F768B2B-A06B-4AE7-84EE-C5D86698AB3B V1 EN
Where, CUM_LOD_PR
1
= SHD_POW
z
This module calculates the load-shed priority in subnetwork z by comparing the
effective load-shed power MAN_SHD_SN<z> input with the cumulative sheddable
load power CUM_LOD_PR
priority corresponds to the first pth priority so that the cumulative load-shed power
p
is greater than or equal to MUST_SHD_LOD
CUM_LOD_PR
z
power for the pth priority is actual load-shed power ACT_SHD_LOD
can record up to 3 consecutive load-shed priorities, that is, record1 priority
, record2 priority SHD_PRIO_RC2
SHD_PRIO_RC1
z
for the subnetwork. Here, the record1 priority refers to the most
SHD_PRIO_RC3
z
recent load-shedding priority, and record2 priority and record3 priority refer to the old
and older load-shedding priorities respectively.
The priority based manual load-shed action is performed by activation of
input which calculates the load-shed priority same as MAN
MLS_TRG_SN
Z
.
_SHD_PRIO
Z
Equation 19 shows the calculation of total sheddable load power SHDABL_LOAD
subnetwork z.
=
p 19
∑
=
SHDABL LOAD _ SHD POW
z
=
p 1
GUID-B2EDA990-A059-473B-B4AF-74A51B677B2F V1 EN
The load mismatch LOD_MISMATCH
difference of SHDABL_LOAD
If the calculated load-shed priority is greater than zero, this module calculates the
cause of load-shed LS_OPR_STS
Block and trigger module. The cause of load-shed is send to the subnetwork
monitoring function block.
Table 326: The cause of load-shed action
Preference No
1
2
3
4
5
Power management functions
p p
+
_ SHD POW _
z
1
z
p
for each priority in incremental order of p. The load-shed
z
p
_
z
in the subnetwork is calculated as the
z
and RUNNING_LOAD
z
based on the load-shed trigger received from the
Z
load-shed trigger
No trigger
Extended load-shed trigger
Fast load-shed trigger
Slow load-shed trigger
Manual load-shed trigger
Section 7
−1
z
. This cumulative shed
z
. This module
z
and record3 priority
z
.
z
Cause of load-shed
(LS_OPR_STS )
z
No load-shed
Extended load-shed
Fast load-shed
Slow load-shed
Manual load-shed
(Equation 18)
in
z
(Equation 19)
291