BOLT 8T4189 - Caterpillar

The parameters that are related to voltage regulation with reactive droop are listed below.
Rated generator voltage
Generator PT primary voltage rating
Generator PT secondary voltage rating
Voltage set point
Generator frequency
Knee frequency
Integral gain
Derivative gain
Proportional gain
Loop gain
Generator CT current primary rating
Generator CT current secondary rating
Load compensation mode
Droop percentage
Rated generator current
Programmable input (current firmware only)Two primary objectives of parallel generator operation are to share the following system electrical load components:
Real power requirements
Reactive power requirementsThe engine governors will control sharing of the real power requirements (kW). The voltage regulator will control sharing of the reactive power requirements (KVAR) of the total system load. There exists the possibility that the output voltage of one paralleled generator is slightly higher than the other generators that are linked together. The generator with the slightly higher output voltage will supply a lagging reactive current to the other generators connected in the group. The current will circulate between generators, possibly causing ampere overloading. One method of minimizing the effect is to cause an individual generator output voltage to sag, or "droop". The droop is in proportion to the lagging reactive current flow from the generator as measured with a current transformer (CT).For proper reactive load sharing, the regulator must know the following:
The rated generator output current
The CT current at rated generator current
The desired percentage of output voltage droop when the generator is at rated reactive output currentAs reactive lagging generator output current increases, the regulator will cause the output voltage to droop (lower the voltage) proportionally. If the measured reactive output current is leading, the output voltage will rise. In either case, this action will tend to reduce the reactive current for better KVAR sharing with other units. The droop percentage controls how much the generator output voltage will vary for a given amount of reactive current.The polarity of the CT that is used must be correct for the voltage to droop with lagging current flow. The CT must be installed on phase B. Reactive droop compensation and line droop compensation work opposite of one another. Reactive droop compensation and line droop compensation and cannot be used at the same time.