3. AGC power management plant - tie breaker present
In one of the applications a tie breaker is present, and it must be adjusted in the menu 2261 whether only the generator breaker
must be closed or both the generator breaker and also the tie breaker.
The breaker sequence adjustments are the following:
Menu Description Comment
2261 Breaker selection Select breakers to close: GB or GB + TB.
2262 Timer
The timer defines the period from the excitation is started and until the regulation is activated. The
alarms with inhibit set to "Not run status" will be activated after this timer has expired.
2263 Excitation start level The setting defines at what minimum level of RPM the excitation can be started.
2264 Voltage discharge
This timer delays the closing of the GB after removing excitation. The intention of this delay is to let
the voltage of the generator discharge, so that only remanence voltage is present when the GB is
closed.
5.4.5 "Close before excitation" failure
If the starting of the genset does not succeed, then the alarm menu 2270 "Cl.bef.exc.fail" will occur, and the selected fail class will be
executed.
5.4.6 Close before excitation without voltage control
To use close before excitation when the genset controller does not control the voltage, disable the Cl. bef. exc. fail alarm (menu
2270).
5.4.7 Close before excitation – additional control parameters
If the application has been configured to use “Close Before Excitation” (CBE) during start, the controller can do additional things to
handle the sequence correctly.
If, for example, the application is made for backup power (AMF), it can be chosen what the controller should do during cooldown.
The controller is able to make a rerun, which means that if a new start request comes during cooldown, the genset(s) can perfom
the CBE sequence again without stopping the genset(s). To handle the functionality for the rerun and cooldown, some parameters
must be set correctly.
Excitation control during cooldown
At parameter 2266, it is possible to decide how the controller should react during cooldown. At this parameter, it is possible to select
between three settings:
• Excitation follow busbar: By default, the parameter is set to “Excitation follow busbar”. This means that if there is voltage on the
busbar during cooldown of the specific genset, the excitation is ON. If the voltage on the busbar disappears, the excitation is shut
OFF.
• Excitation constant OFF: If the parameter is set to “Excitation constant OFF”, the excitation will be switched OFF, as soon as the
GB is open during cooldown. This feature can be handy if the genset fans are pulled mechanically by the genset. Then the
genset will be able to make a rerun faster.
• Excitation constant ON: If the parameter is set to “Excitation constant ON”, the excitation will be ON until the genset stops or a
new start request comes. This feature can be handy if the genset fans are driven by the voltage from the genset.
Parameter
Item Range Default Note
2266
Excitation control during
cooldown
Excitation follow busbar
Excitation constant ON
Excitation follow busbar
Parameter is not shared
between gensets!
DESIGNER'S HANDBOOK 4189341275A EN Page 94 of 196
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