Basler DGC-2020ES Configuration Instruction Manual page 145

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Ground Faults Detected in Ungrounded System Applications
Step 1: Verify that there is no connection from the neutral connection of the generator to the system
ground.
Step 2: Perform insulation resistance tests on the system wiring to check for insulation integrity in the
overall system.
Step 3: If ground faults are detected on a DGC-2020ES in an ungrounded system application, it is
recommended that potential transformers be employed on the voltage sensing inputs to provide
full isolation between the DGC-2020ES and monitored voltage phases.
Step 4: If potential transformers are in place, remove the connectors from the DGC-2020ES one at a
time. If removal of a connector removes the ground fault, check the system wiring to that
connector and out into the system to verify that connections are secure and all wiring insulation
is in good condition.
Generator Breaker and Mains Breaker
Generator Breaker Will Not Close to a Dead Bus
Step 1: Review the description of how the generator breaker logic element functions contained in the
GENBRK logic element description in the BESTlogic™Plus chapter.
Step 2: Review the section on breaker close requests in the Breaker Management chapter.
Step 3: Navigate to the SETTINGS > BREAKER MANAGEMENT > BREAKER HARDWARE > GEN
BREAKER screen and set DEAD BUS CL ENBL to ENABLE.
Step 4: Verify that the Generator status is stable. The breaker will not close if the generator status is
not stable. Check status by using the Metering Explorer in BESTCOMSPlus and verify that
when the generator is running, the GEN STABLE status LED is lit. If necessary, modify the
settings on the SETTINGS > BREAKER MANAGEMENT > BUS CONDITION DETECTION
screen.
Step 5: Verify the bus status is DEAD. Check status by using the Metering Explorer in BESTCOMSPlus
and verify that when the generator is running, the BUS DEAD status LED is lit. If necessary,
modify the settings on the SETTINGS > BREAKER MANAGEMENT > BUS CONDITION
DETECTION screen.
Step 6: Verify the connections in BESTlogicPlus Programmable Logic to the generator breaker logic
element. The Status input must be driven by an "A" or normally open contact from the generator
breaker. The OPEN and CLOSE command inputs on the left side of the logic block are inputs
for open and close commands. These can be wired to physical inputs if it is desired to have
open and close command switches. If they are wired, they must either be pulsed inputs, or
some logic must be employed so that the open and close command inputs are never driven at
the same time. If these are both driven at the same time, the breaker is receiving open and
close commands simultaneously. The breaker will not change state if it is being commanded to
open and close at the same time.
Step 7: Verify the breaker is receiving a close command. Breaker close command sources are:
• The DGC-2020ES itself when the automatic mains fail transfer (ATS) feature is enabled.
The DGC-2020ES itself when the RUN WITH LOAD logic element receives a Start pulse in
•
the programmable logic.
DGC-2020ES
15-3
Troubleshooting