Kohler EKOZD Series Service page 212

Power Factor Control
The reactive power controller measures and controls
reactive power (kVAR). Power factor is the ratio of the
generator real power to the generator apparent power
(which is the geometric sum of the real and reactive
power). To control power factor, the reactive power
target must vary with changing real power.
The VAR Control mode parameter allows selection
between the kVAR and Power Factor control modes.
VAR control is always used when in load sharing mode.
Note: It is possible to control power factor directly, but
the effect of reactive power variations on the
resultant power factor is very non-linear, making
it difficult to provide consistent power factor
regulation over a broad range of power factor
targets with a single set of gains. The power
factor control modes are listed below.
Baseload
D
Power Factor Baseload mode operates very similarly
to baseload kVAR mode except that the target
reactive power is related to the real load on the
generator by a ratio that is determined from the Power
Factor Baseload Setpoint.
Power Factor Baseload mode is probably the
simplest way of controlling reactive power when a
generator is operating at a fixed real power.
Power Factor Baseload is enabled when Real Power
Baseload is enabled (if the VAR control mode is set to
power factor control). Baseload mode can be used as
a testing mode under supervision, but should not be
used long-term in an islanded application.
Voltage Trim is not active in Baseload mode.
The Reactive Power Controller uses the Power
Factor Baseload gains for operation in Power Factor
Baseload mode.
212 Section 12 Paralleling System Information
System Control
D
System Power Factor Control mode controls the
power factor level of all generators on a paralleling
bus to a target level that is determined by the voltage
bias input. The individual generators calculate their
individual reactive power requirement to meet the
power factor target and control the reactive power to
that requirement.
The bias input only needs to be supplied to a single
generator on the communication bus in order to
control all the generators on that bus. The generator
that is receiving the signal does not have to be
running or paralleled to the other generators, but it
does need to have the system control mode and
external bias enabled. If the signal is sent to multiple
generators in the system, only one of them will control
the bus (the others will be ignored). The preference
order of the generator controllers is based on the
controller serial number.
System Power Factor Control mode provides an
interface that allows the generators to be controlled
by an external controller for soft-unloading/loading
and peak shaving against a distant or uncontrolled
source (such as the utility grid). The target Power
Factor decreases with increasing voltage bias, as
described in the following:
Voltage Bias < 0.5V = 0.75 power factor
Voltage Bias = 0.5V = 1.00 power factor
Voltage Bias = 2.5V = 0.75 power factor
Voltage Bias = 4.5V = 0.50 power factor
Voltage Bias > 4.5V = 0.75 power factor
Voltage Trim is not active in System Power Factor
Control mode.
The Reactive Power Controller uses the System
Power Factor Control gains for operation in System
Control mode.
Soft Load/Unload
The Reactive Power Control runs in power factor mode
any time that the system is soft unloading or loading.
The power factor is set to the final target when soft
loading and to the initial power factor when unloading.
TP-6953 7/19