ABB Relion 630 Series, Technical Manual

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command is active for a load feeder, provided that the calculated load-shedding
priority is less than or equal to the priority setting for the respective load feeder.
• When load-shedding priority is calculated with LSCACLS, various subnetwork
information required for subnetwork display is latched.
• The latched output signals can be reset through the respective reset inputs of each
subnetwork. If a load-shedding action occurs before a reset of the subnetwork, the
old latched outputs are replaced with the new, that is, latest, set of values.
LSCACLS can record up to three load-shedding priorities. All the subnetworks
can be reset from the common reset input. On activation of the reset signal, the
latched outputs in the subnetworks are reset.
• LSCACLS calculates the spinning reserve and the extended load-shedding power
of the subnetworks connected to the adjacent electrical network areas..
• The spinning reserve in the subnetwork is equal to the difference of sum of the
available power of all the sources and the total active power in the respective
subnetwork. The extended load-shedding power in the subnetwork is equal to the
difference of power shortfall and the actual shedding power, provided that the
load-shedding priority is 19 and the cause of load-shedding is fast load-shedding
or extended load-shedding.
If PML630 is configured (cPMS configuration B) to have extended
electrical networks present on both sides and both electrical networks
areas are connected to the same subnetwork, the spin reserve and the
extended load-shedding power to be shared with both the adjacent
PML630s depends on the spin reserve sharing mode or extended load-
shedding sharing mode calculated by NPMMXU.
• LSCACLS also calculates the status to inform if either the spin reserve or the
extended load-shedding power is active. If both the statuses are active, the
extended load-shedding power status takes precedence over the spin reserve
status.
7.3.6 Load-shedding trip command function LSPTRC
• Each instance of LSPTRC receives load-shedding operation information for its
load-shed feeders from the LSCACLS.
• The individual instance of LSPTRC sends operating signals to the corresponding
load-shedding feeders on that busbar.
7.3.7 Subnetwork output function SNWRCLS
• Each instance of SNWRCLS receives load-shedding information for the
corresponding subnetwork from LSCACLS.
• The individual instance of SNWRCLS provides various outputs for the
respective subnetwork for monitoring or supervision purposes.
1MRS757256 F
Section 7
Power management functions
PML630/Compact Load-Shedding Solution 213
Technical Manual