Woodward DSLC-2 - Load Control Modes and Adjustments

Manual 37443A DSLC-2 - Digital Synchronizer and Load Control
Page 164/226 © Woodward
Load Control Modes And Adjustments
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The automatic generator loading functions of the DSLC-2 controls will provide a bumpless transfer of kW and
vars when:
• Synchronized and connected to the load bus (isolated or infinite)
• Switching between the different load control modes
o Load sharing to base load / base load to load sharing
o Droop to load sharing / load sharing to droop
o Droop to base load / base load to droop
• Unloading a generator for separation from the load bus
o Unloads kW and kvar
Load Control Mode Switching
Load control operation is determined by the status of the contacts to the “CB Aux” contact input, terminal 70 and
the load control mode select contact inputs. When the “CB Aux” contact input is open, droop is the only available
operating mode. In single unit operation, speed will decrease as load increases, as described above. In parallel
with a bus, the generator is loaded by increasing the speed reference. The DSLC-2 control will provide the droop
signal required for stability. When the “CB Aux” contact input is closed, the generator is paralleled to a bus, the
load control operating mode contact inputs become effective. These inputs are “Base Load”, terminal 73,
“Load/Unload”, terminal 74 and “Process Control”, terminal 78, as shown in Table 5-1.
DI
CB AUX
DI
Load/
(Unload)
DI
Base Load
DI
Process
Control
DI
Ramp Pause
DI
Setpoint
Raise
DI
Setpoint
Lower
DI
Droop
Tracking
Droop
0
x
x
x
x
x
x
0
Load Sharing
(at unload trip)
1 0 0 0 0 x x 0
Load Sharing
1
1
0
0
0
x
x
0
Base Load
(at unload trip)
1 0 1 0 0 x x 0
Base Load
1
1
1
0
0
x
x
0
Base Load Raise
1
1
1
0
0
1
0
0
Base Load Lower
1
1
1
0
0
0
1
0
Ramp Pause
1 x x x 1 x x 0
Base Load Remote
1
1
1
0
0
1
1
0
Process Control
1
1
x
1
0
x
x
0
Process Raise
1
1
x
1
0
1
0
0
Process Lower
1
1
x
1
0
0
1
0
Process Remote
1
1
x
1
0
1
1
0
Droop Tracking
1
x
x
x
x
x
x
1
Table 5-1: Load control modes DSLC-2
The DSLC-2 control base load mode is selected by a closed “Base Load” contact and a closed “Load/Unload”
contact. This function can be used in one of two modes, either as a control to load against a utility or to isolate a
single generator set from a load sharing system and operate that set to a specific load. The second mode can also
be used when a controlled unload is desired without taking the generator set off line.
The DSLC-2 control also includes a ramp pause function that allows for temperature, oil pressure, etc., to reach
the desired operating point. The pause function is activated by an external contact closure to terminal 75. If at any
time during the load or unload ramp, the pause contact is closed, the load ramp is held until the pause command
is removed.