InteliMains
NT
, SW version 3.2.0
InteliMains-NT-MCB-MGCB-3.2.0-Reference Guide.pdf,
©ComAp – April 2015
130
7.29 Soft Unload with support of I Aux measurement
When one group of gen-sets is connected to several Mains incomers in AMF function, the built-in Soft
Unload with I Aux function can be used to do the soft unload in steps. This prevents powering of all
loads from one Mains incomer for happening. There are two possible settings, that allow connecting of
the auxiliary current measurement (one phase measurement on phase L3) to be connected either on
bus or on the load line directly. Position of the measurement connection for both settings is shown
below.
ProcessControl:
Soft Unload
= AuxCTGen
ProcessControl:
Soft Unload
= AuxCTLoad
Study the following example if you need to know more about this function. The first shematics shows
what happens if the function is not used. Loads are returning from Island operation after Mains is OK
again. This results in powering of all loads via first Mains incomer that is synchronized to the gen-set
group.
G
G
G
Sy
n
chron
izati
on
G
G
Gen-set unloading
GCB open level
Power
If the Soft Unload is used, once the power measured using the auxiliary current measurement
(multiplied by 3) goes below
Sync/Load ctrl:
MGCB open level
the MGCB is opened and InteliMains
controlling the second Mains incomers starts the procedure. Finally the third InteliMains transfers its
load and gen-set is stopped. This correct behaviour is shown in the next schematics.
