Load Shedding - ComAp IG-NT GC Reference Manual

LOAD
MCB
Controller
ProcessControl: Base PF
ProcessControl: PF ctrl PtM = BASEPF
LOAD
MCB
Controller
ProcessControl : Import PF
PF ctrl PtM = PF IM/EX
ProcessControl :
ProcessControl : I/E- Qm meas = ANALOG INPUT

Load shedding

Load shedding function is dedicated for tripping of non-essential load in case of high generator current, or
drop of generator frequency above/below preadjusted limits, for preadjusted time.
All LOAD SHED outputs are activated (closed) to trip the unessential load when gen-set goes to island:
a) When GCB is closed after mains fail and gen-set starts in AUT mode.
b) When MCB opens from parallel to mains operation in AUT mode.
c) Before MCB is opened in SEM mode by button.
The load shedding function is active in all controller modes except OFF and
Load shedding has ten steps and each step is linked with its own Load shed x binary output. The non
essential load shedding is based on generator current and generator frequency. There is only one level for
current load shedding and one level for frequency load shedding for all 10 steps, as well for reconnection
level and delay. Load shed can only move from one step to the next, e.g. No LoadShed to LdShed S1 to
LdShed S2 to LdShed S10 and vice versa.
If manual reconnection of the load is desired, the AutoLd recon setpoint needs to be disabled (AutoLd recon
= DISABLED) and the MAN load recon 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
at that moment.
The current load shedding can be activated in case any of phase current exceeds the adjusted limit. The
reconnection is able only in case all of the current values are below reconnection level.
Inteli NT GeCon-MARINE SPI, SW Version 3.2, ©ComAp – July 2015
IGS-NT-GeCon-MARINE-SPI-3.2.PDF
GCB
AVR
Actual PF
Requested PF
GCB
AVR
Actual I/E PF
Requested I/E PF
LOAD
MCB GCB
Controller
Actual I / E PF
Requested I /E PF
Import PF
ProcessControl :
PF ctrl PtM = PF IM / EX
ProcessControl :
ProcessControl : I / E - Qm meas = IM 3 CT INPUT
MAN.
AVR
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