Basler Electric DGC-2020 - Manual (Page 588)

K
i
- Integral Gain
Set the initial value of K
i
to be a tenth of the value set for K
p
in both machines.
Each time K
i
is set in both machines, parallel the machines and check for stable kvar sharing. Then, open
the generator breaker on the second generator and check that both units are still stable. If the system is
not stable, lower K
i
and repeat the test.
Repeat this procedure, raising K
i
in both machines until the system is unstable, and then lower it to the
highest value yielding stable operation.
Repeat for various levels of kvar load if a means of varying kvar load is available.
K
d
-Derivative Gain
If the performance with K
p
and K
i
alone is satisfactory, it is recommended K
d
be left at a value of zero. K
d
can amplify noise in a system so it should be used with great care. Otherwise K
d
, the derivative controller
gain, can be used in conjunction with T
d
, the noise filter constant, to reduce overshoot obtained with PI
control. Setting K
d
and T
d
is an iterative process.
In both machines start with mall values of K
d
that are 1/10 th K
p
or 1/10 th K
i
, whichever is smaller. Tuning of
K
d
can be achieved through the following steps. Set kvar control K
d
in both machines, parallel them
together, and check for stability. Then, drop the second generator and check that both units are still
stable. Raise K
d
in both machines until the system is unstable, and then lower it to half the value where
instability is first attained. Test at various levels of kvar load if a means of varying kvar load is available.
If high frequency noise seems to be entering the system, T
d
is the constant of the low pass filter which
filters the controller input to reduce the effects of such interference when derivative control is employed.
T
d
ranges from 0 to 1 with an increment of 0.001. T
d
=0 is no filtering, T
d
=1 is heaviest filtering. If T
d
adjustment is necessary, set T
d
to 0.001 and see if the noise induced behavior is reduced. Raise T
d
until
desired reduction of noise behavior is achieved. Once T
d
has been set, tune K
d
again. If noise again
appears to be a problem, adjust T
d
until desired behavior is achieved, then retune K
d
.
kW Load Controller Tuning Procedure
Once desired voltage and speed controller performance is obtained, the kW load controller can be tuned.
Two tuning methods are presented, one where the machine is paralleled to the utility to tune systems that
are used for utility parallel operation and a second method where machines are paralleled together to
tune systems employing island parallel operation.
kW Load Controller Tuning Procedure Using Parallel to Mains Operation
In Parallel to Mains operation the kW Load Controller regulates the kW output of the machine to the level
of kW indicated by the Base Load Level setting.
Set the K
p
, K
i
, and K
d
gains in the kW Load Controller to 0. Set the K
g
value to 0.1. Enable the kW Load
Controller. The generator must be paralleled to the utility (as indicated by the Parallel to Mains element in
logic) in any of the tuning steps where the system is being tested for stable operation.
K
p
- Proportional Gain
Set an initial value of K
p
= 1 in the kW Load Controller.
Set K
p
on kW Load Controller. Synchronize the generator to the utility so that kW control becomes active.
Verify that stable kW control occurs. If the kW control seems unstable, lower K
p
and try again. Assuming
operation appears stable, change the base load setpoint in 10% steps and check for stable operation.
Since K
i
is zero at this point, there may be some error. Most importantly, verify stable kW control is
achieved.
Raise K
p
and repeat the test until unstable operation occurs. Then lower K
p
to the highest value where
stable operation was attained.
If it is not possible to obtain stable kW controller operation, it may be necessary to reduce the control
gains in the engine governor which has its bias input driven by the LSM-2020.
K
i
- Integral Gain
Set the initial value of K
i
to be a tenth of the value set for K
p
.
Each time K
i
is set, synchronize the generator to the utility so that kW control becomes active. Check that
operation appears stable. Change the base load setpoint in 10% steps and check for stable operation. If
the system is not stable, lower K
i
and repeat the test.
C-6 DGC-2020 Tuning PID Settings 9400200990 Rev X