InteliMains
NT
, SW version 3.2.0
InteliMains-NT-MCB-MGCB-3.2.0-Reference Guide.pdf, ©ComAp – April 2015
7.6.6 Load shedding based on active power
Load shedding is a function that automatically disconnects and reconnects various loads depending
on several user defined parameters. The load shedding based on active power is activated by setting
the setpoint Ld shed mode to PWR ONLY.
Important setpoints: all setpoints in group Load shedding
The load shedding function is active in all controller modes except OFF. Load shedding works based
on mains import value or the total gen-set group active power (setpoint Load shedding:LdShedBased
on).
Load shedding has three steps and each step is linked with its own Load shed binary output
(LDSHED STAGE X). There are three load shed levels and delays for all three steps as well as recon
levels and delays (setpoints in Load shedding group Ld shedLevel1-3, Ld shedDelay1-3, Ld
reconLevel1-3, Ld reconDelay1-3). Load shed can only move from one step to the next, e.g. “No
LoadShed” to “LdShed stage 1” to “LdShed stage 2” to “LdShed stage 3” and vice versa.
If manual reconnection of the load is desired, the Load shedding:AutoLd recon setpoint needs to be
disabled (DISABLED) and the MANUALLDRECON binary input needs to be configured.
Rising edge on this input resets the controller to a lower stage, but only if the load is under the Ld
recon level for Ld recon delay at that moment.
Depending on Load shedding:Ld shed active setting load shedding is active never (DISABLE), during
island operation (ISLAND ONLY), during island operation with special function when transition to
island operation occurs (ISL + TRIP PARAL) or all the time (ALL THE TIME)
EXAMPLE:
When Ld shed active = ISL + TRIP PARAL, all load shed outputs are activated (closed) to trip the
unessential load when gen-set group goes to island:
a) Immediately when MGCB closes after mains fail and gen-set group is instructed to start in
AUT mode (MGCB application only).
b) After EmergStart del elapses when mains fail and gen-set group is instructed to start in AUT
mode (MCB application only).
c) Immediately when MGCB is closed in MAN mode by button (transit to island from parallel
operation).
NOTE:
If no Load Shedding outputs are configured, there is no record to history and no screen timer
indication of the activity of this function.
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