Manual 37443A DSLC-2 - Digital Synchronizer and Load Control
© Woodward Page 13/226
Load Control
≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡≡
Load control begins at breaker closure when the load control function takes control of the DSLC-2 speed bias
output directly from the synchronizer. The matching of synchronizer slip frequency to initial load (unload trip
level) can result in a bumpless transfer to load control. On command, the adjustable ramp allows smooth, time-
controlled loading into base load, isochronous load sharing or process control. A ramp pause switch input allows
holding of the load ramp for warm-up or other purposes. The base load control is an integrating controller. The
integrating base load control provides accurate load control when in parallel with a bus where frequency may
vary. The DSLC-2 control provides switch inputs to allow raising or lowering the internal digital base load refer-
ence. The control also provides an analog input for remote load setting.
When unloading, an adjustable unload ramp provides time controlled unloading to the unload trip level. When
load reaches the unload trip level, the control issues a breaker open command to separate the generator set from
the system. The ramp pause switch input is in effect while unloading to allow holding of the unload ramp for
cool-down or other purposes.
The load and unload ramps also provide smooth transition between base load, isochronous load sharing and
process control any time the operating mode is changed.
The DSLC-2 control includes several additional load control features:
• Load droop operation provides safe operation in parallel bus applications in the event of a circuit breaker
aux contact failure.
• A frequency trimmer function provides accurate frequency control in isochronous load sharing systems
by compensating for small variations in speed setting between units.
• Adjustable load switch output with independent pick-up and drop-out points provides a signal when the
specified load is exceeded. The load switch output can be selected as a reverse power trip.
• 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.
• A droop tracking function is available automatically by a network fault or by a discrete input.
To Next Page
Loading...
