Basler Electric DGC-2020 - Manual (Page 183)

O Dead Gen Close Enable: Disable or Enable.
Breaker Hardware One-Line Diagram
A one-line diagram of the breaker hardware setup can be displayed on the front panel. This diagram
changes in real time to reflect the current state of the configured breakers. See Section 2, Human-
Machine Interface for details.
Mains Failure
When two breakers are configured (enabled), the DGC-2020 can be enabled to automatically transfer
load power from the mains to the genset during a mains failure
A . This feature also enables the DGC-2020
to transfer the load back to the mains once mains power is restored. Settings include a transfer delay B ,
return delay C , max transfer time D , and max return time E .
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
F 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.
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-2020 starts the generator after the transfer
time expires. The DGC-2020 opens the mains breaker either before the engine starts or after the
generator is stable based on the Mains Breaker Open Configuration
G setting. After the mains breaker is
open, the DGC-2020 closes its generator breaker to drive the load. When the mains power returns, after
the Mains Fail Return Delay time expires, the generator opens its generator breaker and then closes the
mains breaker. If the in-phase monitor
H is enabled and the Mains Fail Return Delay time has expired, the
generator waits until it detects that the phases are aligned between the generator and the mains before
performing the open transition from the generator back to the utility.
An Open Transition Delay I is provided to allow a user-specified amount of time where both breakers are
open. For example, this may be used to prevent damage to large motors in the load by allowing them to
spin down completely during open transitions. The Open Transition Delay is active when both the
generator and mains breakers are open, or when the mains breaker is closed and the mains bus is dead.
In closed transitions, when a mains failure occurs, the DGC-2020 starts the generator after the transfer
time expires. The DGC-2020 opens the mains breaker either before the engine starts or after the
generator becomes stable based on the Mains Breaker Open Configuration setting. After the mains
breaker is open the DGC-2020 closes its generator breaker to drive the load. When the mains power
returns, after the Mains Fail Return Delay time expires, the generator synchronizes to the utility and
closes the mains breaker, paralleling the generator to the utility. While paralleled to the utility, the
generator will ramp down load until the load is at or below the level of the Breaker Open Setpoint or until
the generator has been paralleled to the utility for the maximum allowed time as specified by the Max
Parallel Time
J setting. Finally, the generator opens its generator breaker, leaving the load on utility power,
cools down, and stops. Since the kW output of the generator is ramped during closed transitions, a load
sharing module (LSM-2020) is generally required to provide governor bias signals to the engine governor.
Closed transition override can be enabled through BESTlogicPlus Programmable Logic. When the Closed
Transition Override element is set true, it forces a closed transition due to mains failure, overriding an
open Mains Fail Transfer Type setting.
If the Alarm State Transfer to Mains K setting is enabled, the DGC-2020 can transfer the load to a stable
utility when in the alarm state. If this setting is disabled, the DGC-2020 will not perform any transitions of
the load to or from the utility when in the alarm state.
When enabled, Reverse Rotation Inhibit L prevents automatic load transfer due to a mains failure when the
machine is determined to have reverse phase rotation.
The BESTCOMSPlus Mains Fail screen is illustrated in Figure 4-62.
9400200990 Rev X DGC-2020 BESTCOMSPlus
® Software
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