9469300994 9-15
DGC-2020HD Troubleshooting
contacts to remove the DGC-2020HD from the load share system when the generator breaker
is closed.
Step 10: If it appears that something is driving the load share line but it is not the DGC-2020HD on one
of the non-running units, search for an external device that is driving or loading down the load
share lines.
Step 11: Repeat the preceding 3 steps for each machine.
Load Sharing Works Correctly, but a Single Unit Slows Down
With all units running, load sharing works correctly, but a single unit slows down after the generator
breaker is closed.
Step 1: Disconnect the load share line from the DGC-2020HD. Run the single machine with load, and
verify that it loads and unloads correctly, and runs at the correct speed. Repeat for each
machine.
Step 2: Re-attach load share lines to all DGC-2020HDs that are part of the load sharing system. Run
the Single machine with load, and verify that it loads and unloads correctly, and runs at the
correct speed. If the machine slows down when the generator breaker is closed, check the load
share line voltage. It should be equal, on a normalized basis, to the normalized kW produced
by the generator. As an example, if the generator is loaded to 50% capacity, the Load Share
Line voltage should be at the midpoint of the range. If it is not, something is driving the load
share line that should not be. The single unit should be the only device driving the load share
lines.
Step 3: Disconnect the load share lines from each non-running machine and see if the speed of the
running machine is correct. If a particular DGC-2020HD on a non-running machine seems to
affect the performance of the running machine, that DGC-2020HD may be damaged such that
the Load Share Line contacts are sticking, causing the DGC-2020HD to drive the load share
line even though the generator breaker is open. Tap the relays to see if the problem clears up.
If so, a faulty DGC-2020HD relay is indicated. Replace the DGC-2020HD, or wire in external
contacts to remove the DGC-2020HD from the load share system when the generator breaker
is closed.
Step 4: If it appears that something is driving the load share line but it is not the DGC-2020HD on one
of the non-running units, search for an external device that is driving or loading down the load
share lines.
Step 5: Repeat the preceding 3 steps for each machine.
Group Start and Group Stop Requests
Generator Does Not Start During an Island Group Start Request or Mains Parallel Group
Start Request
Step 1: Verify that a Group Start Request is active. In the BESTCOMSPlus Metering Explorer, navigate
to DGC-2020HD > System Status > Breaker. Examine the Group Start Req column for nonzero
entries. Nonzero entries indicate active group start requests.
Step 2: Check that the generator to start is in the same Generator Group in the Group Segment
Settings as the breaker generating the Group Start Request. Only generators in the same
Generator Group as the Generator Group configured for the breaker issuing the Group Start
Request will respond.
Step 3: Verify that the generators to be started are in Auto mode, the System Type under the System
Settings is configured as Segmented Bus System, and Sequencing and Demand Start/Stop are
enabled.
Step 4: Verify that the generator to be started does not have an active Run with Load Stop as this will
supersede Group Start Requests and prevent the generator from starting.
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