Basler Electric DGC-2020 - Manual (Page 323)

i. Dead Bus Voltage Threshold and Activation Delay. When the voltage of the
generator is below this threshold for the duration equal to the activation delay, the
generator is deemed “Dead”.
ii. Gen Stable Over and Under Voltage thresholds and Over and Under Frequency
thresholds and the Bus Stable and Bus Failed Activation Delay times. When the
generator voltage and frequencies are within the specified ranges for the duration
equal to the Bus Stable Activation Delay, the generator is deemed “Stable”.
Otherwise, it is deemed “Failed”.
b. Bus Sensing. See Figure 7-38.
i. Dead Bus Voltage Threshold and Activation Delay. When the voltage of the bus is
below this threshold for the duration equal to the activation delay, the bus is deemed
“Dead”.
ii. Bus Stable Over and Under Voltage thresholds and Over and Under Frequency
thresholds and the Bus Stable and Bus Failed Activation Delay times. When the bus
voltage and frequencies are within the specified ranges for the duration equal to the
Bus Stable Activation Delay, the bus is deemed “Stable”. Otherwise, it is deemed
“Failed”.
CAUTION
The bus condition parameters are critical because they determine when a
breaker can be closed. The generator breaker can be closed when any one of
the following is true:
•
The generator is stable and both breakers are open
•
The generator is stable and the bus is stable
•
The generator is stable, the bus is dead, and the dead bus close
enable setting is set to enabled
•
The generator is dead, the dead gen close enable setting is set to
enabled, the bus is dead, and the dead bus close enable setting is set
to enabled
The mains breaker can be closed only when the generator is stable and both
breakers are open, or the generator is stable and the bus is stable.
6. Place the unit in AUTO. The unit is now configured for generator breaker control. It can be tested by
driving the RUN WITH LOAD logic element true, or setting up the exercise timer for a loaded test, or
by starting the unit in RUN or AUTO mode and giving it CLOSE and OPEN commands from the
physical inputs if they are available for breaker control.
Synchronizer
Some applications require a generator set that is paralleled with other generators or a utility bus. In order
to parallel the generator, the speed and the voltage of the generator must be properly matched to the
source that the generator is being paralleled to. This is done by properly adjusting the generator’s speed
control governor and automatic voltage regulator. Synchronization can be achieved manually by an
operator or by the use of an automatic synchronizer.
The DGC-2020 digital genset controller has an integrated automatic synchronizer as an option to perform
synchronization. The controller monitors the voltages, frequencies, and phase relationships of both the
generator and the bus. It then sends a signal to the governor to increase or decrease the speed of the
engine to match the frequency and match the generator phase angle to the bus phase angle. It will also
send a signal to the voltage regulator to match the voltage levels. Once all of these conditions are met,
the controller will send a breaker close signal to the generator circuit breaker.
There are two types of automatic synchronizers available. A phase lock type of automatic synchronizer
controls the frequency of the generator and brings it into the predetermined phase angle window. After a
time delay expires while in the window, the close signal is given to the generator circuit breaker. The
anticipatory style of automatic synchronizer controls the slip frequency between the generator and the
bus. The synchronizer calculates the timing of the closing signal to allow the generator breaker to be
9400200990 Rev X DGC-2020 Setup 7-35