Scada
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5.8.5.1 ADJUSTING GAIN AND STABILITY
Initial Setup
Typically the DSE factory settings are suitable for most systems. However occasionally it may be necessary to
adjust them, but only after checking the gain and stability settings of the speed governor/AVR.
Start with gain and stability at the minimum settings. Increase gain until the engine speed becomes unstable,
then half the gain setting.
Now increase the stability setting until the engine speed again becomes unstable, and then lower a little.
You may need to perform the synchronising process a number of times to see the effect of your changes. You
can also ‘knock’ the governor actuator, or change the ‘slip frequency’ setting to disturb the engine speed and
force the controller into making further changes.
Troubleshooting
Generally a problem with the gain (too high or too low) will result in a fast oscillation of the parameter being
controlled. A slow rolling oscillation usually indicates that the stability is too high or too low.
Remember that the DSE module is not the only device with gain/stability. The engine governor and AVR also
have these settings. An incorrectly set governor/AVR cannot be corrected by the DSE controller. You must
ensure correct settings for these devices before changing the DSE module settings.
In general, engine governors need lower gain when in parallel with the mains supply than they do for single
set operation or paralleling with other generators.
NOTE: An over damped response will result in a slower control process. An under damped
response (overshooting the target) will lead to an unstable control process.
Either case could lead to undesirable consequences such as over-current or reverse power, resulting
in generator shutdown, and loss of supply to the load.
Under damped response. Gain/stability must be
adjusted
Over damped response. Gain/stability must be
adjusted
Critically damped response. Gain and stability are
correctly set.
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