Kohler EKOZD Series Service page 204

12.1.3 Internal Paralleling
The speed and voltage bias are ignored after the breaker
is closed in internal paralleling operation mode except in
System Sync mode and System Load Control mode
(described separately). The bias inputs are accepted in
passive synchronization mode or when synchronization
is disabled (set to off or sync disabled input is on).
Enabling these inputs will have no effect on the operation
of the generator in normal operating modes.
The generator controller will enter internal paralleling
mode automatically if the PGEN communication wires
are connected to another Decision-Makerr 3500
controller (if External Paralleling is desired, do not
connect the communication wires between two
Decision-Makerr 3500 controllers).
To force a controller to Internal Paralleling mode without
PGEN communication, set the Stand Alone Operation
parameter to true (Under Synchronization Control in
SiteTecht, in Generator Info -> Paralleling Operation ->
Paralleling Setup Menu on the controller). This will make
the controller behave like a paralleling controller even if
it doesn't see another generator on the communication
lines. This is intended for an application where the
Decision-Makerr 3500 controller is controlling a
motor-operated breaker on the output of the generator,
but there are no other generators on the paralleling bus.
In Internal Paralleling mode, all the Decision-Makerr
3500 controllers that are communicating over PGEN will
behave as a system—they are aware of the status of the
other generators in the system. A start signal to any
generator in the system will start all generators in the
system.
Breaker Control
In Internal Paralleling mode, the Decision-Makerr 3500
controller sends signals to a motor-operated breaker to
open and close. These signals are provided as Relay
Drivers, and must be connected to pilot relays to operate
the circuit breaker.
Bus Sensing
The Decision-Makerr
three-phase, line-to-line voltage on the paralleling bus,
allowing for loss of phase detection, phase rotation
verification, and accurate voltage matching with
imbalanced load.
The bus sensing must be connected on the opposite side
of the motor-operated circuit breaker from the generator
connections to allow the generator to measure and
control the phase relationship across the circuit breaker.
204 Section 12 Paralleling System Information
3500 controller measures
First-On Logic
The Decision-Makerr 3500 controller uses dynamic
first-on logic. The first generator to reach rated speed
and voltage will be given permission to close the
paralleling breaker. If two units reach rated speed and
voltage at the same time, the one that was powered up
first or that has the lower controller serial number will be
permitted to close first. First-On negotiation is
performed over the PGEN communication lines.
Synchronization
The Decision-Makerr 3500 controller can actively
synchronize the generator to the paralleling bus. The
personality profile for the generator will have default
synchronizing settings that will permit successful
synchronization under normal conditions.
Synchronization is achieved by controlling the speed
bias to the ECM and the voltage bias to the Voltage
Regulator. These biases are internally derived and are
not related to the speed and voltage bias inputs.
Passive synch mode does allow external control of the
speed and voltage bias, but closes the breaker only when
the generator is in synchronism with the paralleling bus.
Load Sharing
The Decision-Makerr 3500 controller will attempt to
equalize the percent loading of each of the generators
that is connected to the bus in the paralleling system.
This is the normal mode of operation in parallel.
Other paralleling modes should only be used in
applications with additional controls that operate in
parallel with the utility, but are listed below for reference:
Baseload Mode. The controller adjusts speed and
D
voltage in an effort to maintain the power output to an
adjustable parameter. This mode can be used for
testing, but increases risk of reverse power or reverse
VARs when used in a paralleling system.
System Sync Mode. All generators in the paralleling
D
system will respond to the speed and voltage bias
input of the generator with this mode enabled. This is
intended to allow external gear to bring the entire
generator bus into synchronism with the utility.
System Load Control Mode. All generators in the
D
paralleling system adjust speed and voltage in an
effort to maintain the power output to a target set by
the speed and voltage bias from an external system
load control device.
TP-6953 7/19