Kohler EKOZD Series Service page 247

If all the generators are running, the order re-sorts
automatically any time the runtime hours of a higher
order generator drop below the hours on a lower order
generator. This will not typically occur while all
generators are running, as they will all be acquiring
runtime hours at the same rate.
If a generator starts because the load increases, the
order may re-sort as soon as it connects to the
paralleling bus, hence the runtime hours will be
equalized before the difference reaches the
threshold.
Runtime control mode is intended for applications
where the generators require wear-leveling, such as
a prime-power application.
Fuel Level: The Generator Start/Stop Order is
D
selected automatically by the controller based on the
fuel level measured by each generator. In this mode,
the generator with the highest fuel level (as measured
in percentage) will be assigned the lowest order
(starting first, stopping last), with each sequential
order number being assigned to generators of
decreasing fuel level. The intent is to equalize fuel
level between the units.
If the generator system is supplying the load,
Generator Management implements a Fuel Level
Threshold to avoid starting and stopping generators
every time the fuel level changes (which could
happen frequently if the fuel is moving). The Fuel
Level Threshold is added to the fuel level of
generators that are running (for the purpose of
comparison), preventing
starting and stopping of generators.
If all the generators are running, the order re-sorts
automatically any time the fuel level of a lower order
generator drops below the fuel level on a higher order
generator. This will not typically occur while all
generators are running, as they will all be using fuel at
the same relative rate (if the tanks are sized
appropriately for each generator).
If a generator starts because the load increases, the
order may re-sort as soon as it connects to the
paralleling bus, hence the fuel level will be equalized
before the difference reaches the threshold.
Fuel Level Control mode is intended to equalize fuel
level in a system of generators where each generator
has a separate fuel tank—it is intended to prevent the
case where one generator runs out of fuel while the
others have plenty.
TP-6953 7/19
excessively frequent
13.4.2 Enabled
This permits disabling all Generator Management
features. When Generator Management is disabled, a
generator will not alert the user of a Generator
Management configuration mismatch. Any generators
in the paralleling system with Generator Management
disabled will run if they are in auto and are receiving a
start signal (they will not stop if they are not needed).
Nodes with Generator Management enabled may still
see a configuration mismatch if a disabled node is
configured differently.
13.4.3 Order
The order that a generator will start and stop in the
Generator Management sequence—higher orders start
last and stop first. This parameter is only adjustable in
Manual Mode. The order of each of the generators in the
paralleling system must be different for Generator
Management to function. Generator Management will
attempt to correct an order conflict, but can only do so to
a limited extent.
If a generator controller is powered down or disconnected
from the communications network, the remaining
controllers will attempt to re-sort the order so that each
generator has a unique and sequential order—the re-sort
is not always successful in manual mode.
It is important to verify the Start/Stop Order of each
generator if power is cycled to one or more generators in
a paralleling system where Generator Management is
used in manual mode.
13.4.4 Start Percentage
The Percentage of Rated Capacity on the paralleling
system (the generators that are running and are active
in Generator Management) above which a generator is
considered for starting.
Only a generator which is available, not running, and is
enabled for Generator Management can be started by
Generator Management.
Generator Management uses the start percentage to
calculate the Start kW for this generator.
The Start Percentage should be set so that the
generator system starts enough generators that any
transient loading can be supported by the running
generators, or to keep an additional generator running
for redundancy. The default (80%) works for most
applications, but applications with large switching loads
may require a lower setting for the Start Percentage.
Section 13 Generator Management Information 247