Basler Electric DGC-2020HD - Manual (Page 91)

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correspond to the change in breaker state. If an external source opens the breaker, the DGC-2020HD
issues a breaker open output. Likewise, if an external source closes the breaker, the DGC-2020HD
issues a breaker close output.
Enabling the Dead Bus Close Enable setting allows the DGC-2020HD to close the generator breaker onto
a dead bus. This can be used to ensure that only one machine closes onto a dead bus at a time, thus
preventing multiple machines simultaneously closing to the dead bus out of phase with each other. When
this setting is disabled, the DGC-2020HD can only close the generator breaker onto a stable bus.
All generator and mains breaker hardware settings on the Breaker Hardware screen are disabled when
the system breaker configuration is set to No Breaker Control on the System Settings screen.
Start up Synchronization
Start up synchronizing is a means of bringing up a system of generators when the generator breakers are
closed to a dead bus and the generators are stopped. Normally, it’s not possible to close the generator
breaker when the generator is dead. To permit a closure of the generator breaker from a “dead” generator
to a “dead” bus, both the Dead Bus Close Enable and the Dead Gen Close Enable settings must be
enabled. After all generator breakers are closed, the gensets are started and synchronized when the
AVRs are turned on. The user must develop logic to start the generators and turn on excitation in the
voltage regulators at the correct time for orderly system startup.
Caution
Use caution when connecting “dead” generators to a “dead” bus. Undesired
operation or system damage could occur if the bus becomes “live” while
“dead” generators are connected to it.
Mains Failure
For generator and mains breaker configurations, the DGC-2020HD can automatically transfer load power
from the mains to the genset during a mains failure. This feature also enables the DGC-2020HD to
transfer the load back to the mains once mains power is restored.
Note
Automatic breaker operation can be disabled through BESTlogicPlus
Programmable Logic. When the Auto Breaker Operation Inhibit element is set
true, it prevents all automatic breaker operation.
When Mains Fail Transfer is set to enabled, the machine is configured as a mains fail machine or standby
power machine that takes over when utility power fails. There are two types of transitions between the
generator and the utility that are set with the Mains Fail Transfer Type setting: (1) Open transitions in
which the generator and mains breaker are never closed at the same time, and (2) Closed transitions in
which the generator parallels to the utility for a short time to transfer load to the generator from the utility
(a load takeover) or transfer the load from the generator to the utility.
Note
The Mains Fail Transfer function can be disabled through BESTlogicPlus
Programmable Logic. When the Mains Fail Transfer Inhibit element is set true,
it prevents automatic load transfer due to a mains failure.
In open transitions, when a mains failure occurs, the DGC-2020HD starts the generator after the transfer
time expires. The DGC-2020HD opens the mains breaker either before the engine starts or after the
generator is stable based on the Mains Breaker Open Configuration setting. After the mains breaker is
open and the Open Transition Delay time expires, the DGC-2020HD closes its generator breaker to drive
the load. When the mains power returns, after the Mains Fail Return Delay time expires, the DGC-
2020HD opens its generator breaker. Then, after the Open Transition Delay time expires, the mains
breaker closes. If the in-phase monitor is enabled and the Mains Fail Return Delay time has expired, the
DGC-2020HD Breaker Management