Kohler EKOZD Series Service page 261

14kW 15kW
Generator #1 Generator #2 Generator #3
(50kW rating) (50kW rating) (50kW rating)
Load
Shed
Panel
Figure 14-9 All Generators Supplying the Paralleling
Bus, Priority 1 Added
With load priority 1 added, the total system load is
43 kW, shared between the three generators. This
amounts to 29% of the rated capacity of the system,
increasing the time delay to add priority 2 to 55 seconds.
With priority 2 online, the system load is 34%, requiring
85 seconds to add priority 3.
With priority 3 online, the system load is 36%, requiring
104 seconds to add priority 4.
With priority 4 online, the system load is 43%, requiring
260 seconds (just over 4 minutes) to add priority 5.
With priority 5 online, the system load is 51%, requiring
2400 seconds (40 minutes) to add priority 6.
After all load priorities are added, Generator
Management may elect to stop a generator, but only if
the stop percentage is above 81% (the load on two
generators). If a generator is stopped, no loads will
shed, as the percent of system capacity is below the
Generator Overloaded Percent (85%).
TP-6953 7/19
14kW
25kW 18kW 8kW 3kW 10kW 12kW 5kW
Critical Most
loads important important
Additional
non-
non-critical
critical
loads
loads
Load
Shed
40kW
Panel
Generator #1 Generator #2
(50kW rating) (50kW rating)
Least
non-
critical
loads
Figure 14-10 Generator #3 Stopped, All Priorities
Note: Priorities 3 and 6 will remain added unless the
system is overloaded, even though they are
controlled by the generator #3 controller, as the
Load Management logic in the generator #3
controller looks at bus frequency and bus loading
to make Load Management determinations.
Note: The case above is unlikely, as Generator
Management will not typically be configured to
stop a generator above 80%, as this does not
leave very much available capacity for changing
loads.
If the Stop Percentage for Generator Management is
changed, it should not be configured to be above the
Generator Overloaded
Management may force a priority to shed when a
generator is stopped, nor should the Start Percentage
for Generator Management be above the Generator
Overloaded Percent, as this may result in loads being
shed while an available generator does not start to
supply the loads.
If the Minimum Load Priority Online for Generator
Management is set to 6, the third generator will start as
soon as Load Management sheds priority 6. This would
result in priority 6 re-adding and the generator stopping
again, establishing a repeating cycle.
Overload Shed and Underfrequency Shed use identical
timing and thresholds to the single generator case, but
use the bus % kW and the bus frequency to make Load
Management determinations.
41kW 0kW
Generator #3
(50kW rating)
25kW 18kW
Load Critical Most
Shed loads important
Panel non-
critical
loads
Added
Percent,
Section 14 Load Management
Load
Shed
Panel
8kW 3kW 10kW 12kW 5kW
Least
important
Additional
non-
non-critical
critical
loads
loads
as Generator
261