Manual 02007
DSLC Digital Synchronizer and Load Control
Woodward
3
•
Load raise and lower inputs can be used to adjust speed before
synchronizing.
•
Voltage raise and lower inputs can be used to adjust voltage before
synchronizing.
Process Control (full function models)
A cascade PID process controller is provided for cogeneration, import/export
control, pond level maintenance, pressure maintenance, or other application. An
adjustable bandwidth signal input filter, flexible PID controller adjustments, an
adjustable deadband, and control selectable for direct or indirect action, allow the
process control to be used in a wide variety of applications.
A 4–20 mA (or 1–5 Vdc) process transmitter provides the process signal to the
DSLC control. The control includes an internal digital process reference which
may be controlled by raise and lower switch contact inputs or by an external
4–20 mA (or 1–5 Vdc) remote process reference. The output of the process
control provides the cascade load reference to the base load control.
Adjustable ramps allow smooth entry to or exit from the process control mode.
When the process control mode is selected, an adjustable ramp moves the load
reference in a direction to reduce the process control error. When the error is
minimized, or the reference first reaches either the specified high or low load
pick-up limits, the process controller is activated. When a limit is reached, the
control will hold the load reference at that limit until process control is obtained.
When unloading from the process control, an adjustable unload ramp provides
time controlled unloading to the unload trip level. When load reaches the unload
trip level, the DSLC control automatically issues a breaker open command to
remove the generator set from the system. The ramp pause switch input allows
holding of the unload ramp for cool-down or other purposes.
Additional functions include selectable and adjustable process high and low limit
switches and alarm activation.
VAR/PF Control (full function models)
The VAR/PF functions control the reactive power component of the generator in
parallel systems. In an infinite bus system, the controller compares either the
kVAR load or power factor (selectable) on the generator with an adjustable
internal reference and makes corrections to the voltage regulator until the
desired kVAR load or power factor is obtained. For higher performance, an
analog output can be directly connected to compatible voltage regulators with
analog voltage setting input. The control has raise and lower voltage discrete
inputs for manual voltage adjustment. The control also has raise and lower
contact outputs to activate a voltage regulator MOP when an analog input is not
provided on the AVR.
The DSLC control provides power factor sharing between units for isolated bus
or isochronous parallel systems. The control computes an average power factor
for the system and uses it as the reference input to the power factor controller.
The control includes an adjustable voltage reference and voltage trim function in
the sharing function to maintain system voltage at the desired level.