InteliMains
NT
, SW version 3.2.0
InteliMains-NT-MCB-MGCB-3.2.0-Reference Guide.pdf,
©ComAp – April 2015
66
beneficial in combination with load shedding after Mains failure occurs (i.e. part of the load is
supplied immediately and other parts are connected as other gensets start).
N
OTE
:
System starting sequences may be very different due to their complexity (i.e. gensets which do not
take part in power management, various nominal powers etc.). Each system should be considered
individually.
7.5
StartUpSynchronization
InteliMainsNT now supports StartUpSynchronization function which is available in standard firmware
for InteliGen
NT
and InteliSys
NT
from version 3.1.0.
BusMeasError function was changed so it does not signalize Bus measurement error when there are
gen-sets starting in start up synchronization with their closed GCB and there is no voltage on the bus.
In MGCB application there is a support for closing of MGCB in Island mode (MCB must be opened)
when at lest one gen-set in the same control group indicates that it starts in SUS. This can be used for
soft start on big transformers connected behind MGCB and therefore preventing dangerous
magnetization currents. This behaviour is changed by setpoint
ProcessControl:
MultiSoftStart
.
7.6
Power management
It is important to note that InteliMains
NT
in MCB or MGCB applications is not directly controlling the
power management. The power management is decentralized system and it is resolved individually in
each InteliGen
NT
or InteliSys
NT
running in MINT application (this system synchronizes setpoints so it is
resolved based on the same rules in all controllers and the system is more robust because it does not
depend on a single master). InteliMainsNT controller plays crucial role in the system in the control of
required load in parallel to Mains operation (see the chapter 7.9) and also it can be switched to
MASTER in Automatic priority swap function (see the chapter 7.6.2).
The Power management function decides how many gen-sets should run and selects particular gen-
sets to run. The power management is applicable in cases multiple gen-sets run in parallel to mains or
in the island operation. The function is based on the load evaluation in order to provide enough of
available running power. Since it allows the system to start and stop gen-sets based on the load
demand, it can vastly improve the system fuel efficiency. In other words, an additional gen-set starts
when the load of the system rises above certain level. The additional gen-set stops, when the load of
the system drops down below a certain level. The process of determining gen-set start and stop is
done in each controller; there is no "master slave" system. Therefore, the system is very robust and
resistant to failures of any unit in the system. Each of the controllers can be switched off without
influencing the whole system. Except the situation the respective gen-set is not available for the power
management.
The power management evaluates so called load reserve. The load reserve is calculated as difference
between actual load and nominal power of running gen-sets. The reserve is calculated as absolute
value (in kW / kVA) or relatively to the nominal power of gen-set(s) (in %). The setpoint
Pwr management:
#Pwr mgmt mode
is used to select the absolute or relative mode.
The automatic priority swapping function focuses on efficient run of gen-set in regards to running
hours and gen-set size.
7.6.1
Power management limitations
W
ARNING
!
This section contains important information regarding power management function that are crucial for
the correct function of power management.
