Basler Electric DGC-2020 - Manual (Page 181)

A Pickup: Adjustable from 0.2 to 10 Hz/s in 0.1 Hz/s increments.
B Activation Delay: Adjustable from 0 to 10 s in 0.001 s increments.
C Open Mains Breaker on Trip: Enable or Disable.
D Open Generator Breaker on Trip: Enable or Disable.
E Alarm Configuration: Alarm, Pre-Alarm, or Status Only.
Breaker Management
DGC-2020 breaker management features include the control of two, continuous- or pulse-controlled
breakers, load transfer upon detection of a mains failure, two modes of automatic genset synchronization,
and settings for stable or dead bus detection. Open transitions are implemented in load transfers to and
from the mains.
The description of breaker management is organized as follows:
•
Breaker Hardware
•
Mains Failure
•
Bus Condition Detection
•
Synchronizer
Breaker Hardware
By default, one (generator) breaker is enabled A for control and monitoring by the DGC-2020. In
applications requiring control of a generator breaker and mains breaker, a second (mains) breaker can be
enabled
B and configured.
Breakers controlled by pulse or continuous inputs are supported C . Separate settings for each breaker’s
open D and close E pulse widths are provided as well as a transition delay. During the Transition Delay F ,
open or close outputs are removed to allow any breaker interlocks to reset before a new open or close
output is initialized. This setting accepts values from 0 to 1,000, in increments of 1 second.
During synchronization of the generator with the bus (Anticipatory mode only), the DGC-2020 uses the
breaker closing time
G to calculate the optimum time to close the breaker.
When a close command is issued, the DGC-2020 monitors the breaker status and annunciates a breaker
failure if the breaker does not close within the time defined by the breaker-close wait-time delay
H .
Typically, this parameter is set to be longer than twice the breaker closing time.
The Breaker Fail Output Configuration I setting dictates whether the breaker output is removed or
maintained during the breaker open fail or breaker close fail pre-alarm condition.
After a breaker open or close failure occurs, the DGC-2020 can attempt to reopen or reclose the breaker
a pre-defined number of times. The number of attempts to open
J or close K the breaker and the duration of
time L between each attempt are user-programmable.
When an external device changes the state of the breaker, the External Status Change Action M setting
dictates how the DGC-2020 responds to the state change. The DGC-2020 can ignore external breaker
state changes, always follow breaker state changes, or only follow breaker state changes when in Auto
mode. When the DGC-2020 is following external breaker state changes, it issues outputs that correspond
to the change in breaker state. If an external source opens the breaker, the DGC-2020 issues a breaker
open output. Likewise, if an external source closes the breaker, the DGC-2020 issues a breaker close
output.
The dead bus close enable setting N enables a machine to close its breaker onto a dead bus. This can be
used to make sure only one machine can close onto a dead bus at a time, if desired, preventing multiple
machines closing to the dead bus at the same time, potentially out of phase with each other. When this
setting is disabled, a machine can only close onto a stable bus.
Startup Synchronization
Startup synchronizing is a means of bringing up a system of generators, when the generator breakers are
closed to a dead bus when the generator is stopped. After all breakers are closed, the gensets are started
and pulled into sync when the AVRs are turned on. When enabled, the dead gen close enable parameter
O
allows closure of the breaker to a dead bus when the generator is dead.
Normally, it is not possible to close the generator breaker when the generator is dead. However, in cases
where it is required to connect a generator that is “dead” to a bus that is “dead” for purposes of startup
synchronization, both the generator and the bus must be recognized as “dead”. To permit a close of the
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