Basler Electric DGC-2020 - Manual (Page 194)

FF Parallel To Mains Gain: Adjustable from 0 to 1,000 in increments of 0.001.
GG Droop Percentage: Adjustable from 0 to 10% in 0.001% increments.
HH Voltage Droop Gain: Adjustable from 0 to 1,000 in increments of 0.001.
II Ramp Rate: Adjustable from 0 to 100 %/s in 0.1 %/s increments.
JJ Ramp Overshoot Reduction: Adjustable from 0 to 100% in increments of 1.
Governor Bias Control Settings
The bias control output type A should be set to contact when operating without an optional LSM-2020.
The DGC-2020 adjusts the generator voltage and frequency by issuing speed correction signals to the
generator governor. Correction signals are issued in the form of DGC-2020 output contact closures.
These correction signals can be either continuous or proportional
B . Proportional correction uses control
pulses of varying widths C and intervals D . Initially, long pulses are issued when the voltage and frequency
differences are large. As the correction pulses take effect and the voltage and frequency differences
become smaller, the correction pulse widths are proportionally decreased. Proportional correction pulses
are beneficial in applications where fixed correction pulses can result in overshooting the slip frequency
and regulation offset targets.
When an optional LSM-2020 is connected, the bias control output type A should be set to analog. This
enables a PID controller that controls the bias signal from the LSM-2020 to the speed governor. The
controller adjusts the bias output to drive the error between desired generator speed and measured
generator speed to zero. Settings are provided for proportional gain
E , integral gain F , derivative gain G ,
derivative filter constant H , and loop gain I of the PID controller.
The speed trim enable setting J sets speed trimming to the speed trim setpoint K when the generator
breaker is closed and the machine is not paralleled to the utility.
When the difference between the measured speed and the speed trim set point is less than the trim dead
band
L , the speed trim controller will treat this as zero error. If system operation appears "nervous" when
speed trim is enabled, setting a nonzero dead band may result in smoother system operation. In addition,
if machines do not appear to share kW equally when speed trim is enabled, setting a nonzero dead band
will likely result in improved kW sharing. The Speed Trim Dead Band is in units of Hz.
The Remote Speed Bias setting provides for biasing the speed of a group of generators on a bus, by as
much as ±5%, for synchronizing to the utility. When the Remote Speed Bias setting
M is configured for the
LSM-2020 input or an AEM-2020 input, the speed trim setpoint is calculated based on the specific analog
input. The Remote Speed Bias (%) setting
N corresponds to the maximum and minimum analog input
range.
If speed trimming is enabled in all generators in an islanded system, it is ensured that the system will run
at the speed trim setpoint. If it is not enabled in any units, the islanded system might deviate from the
speed trim setpoint, depending on the initial speed settings of the isochronous governors. Speed trim
should be enabled in all units or disabled in all units of an islanded system. If it is enabled in only a subset
of the units, speed trimming and load sharing might conflict, resulting in unpredictable load sharing and
system frequency.
The BESTCOMSPlus Governor Bias Control Settings screen is illustrated in Figure 4-68.
kW Control - Real Power Control Settings
When enabled O , the DGC-2020, used in conjunction with an optional LSM-2020, can accomplish kW
sharing between similarly equipped generators. kW sharing can be performed via Ethernet or Analog
lines. The communication method is selected using the Load Share Interface setting
P . When an optional
LSM-2020 is not connected, kW control is disabled.
kW control is accomplished with a PID controller that controls the speed bias signal from the LSM-2020 to
the speed governor. The controller adjusts the bias output to drive the error between desired kW
generation and measured kW generation to zero.
Settings are provided for proportional gain Q , integral gain R , derivative gain S , derivative filter constant T , loop
gain U , and Parallel To Mains Gain V of the PID controller.
The percent speed droop to be used when the unit is in droop mode is determined by the droop
percentage setting
W . Speed droop mode is entered any time the generator breaker is open. Speed droop
is also the mode when the generator breaker is closed if kW load sharing is disabled. If it is desired to
disable speed droop, set the droop percentage to 0. The speed droop gain setting
X determines the gain
factor applied to the speed droop percentage to compensate for governor differences and achieve
4-84 DGC-2020 BESTCOMSPlus
® Software
9400200990 Rev X