3-7
supplies sensing voltage to regulator terminal E2. For single-sensing phase models it must be
installed in the line of the three-phase generator that does not supply sensing to the regulator.
c. Figures 3-4 and 3-5 show the correct CT polarity for A-B-C phase rotation sequence. If the phase
rotation sequence is A-C-B, the CT's secondary leads must be interchanged.
a. For reactive droop compensation, connect the CT to its respective regulator as shown on Figures
3-4 and 3-5.
b. A unit-parallel switch shorts the parallel CT secondary to prevent any droop signal from being
injected into the regulating system during single unit operation. The switch may not be required on
parallel droop compensation applications where a voltage drop is not objectionable.
a. On parallel reactive differential compensation applications a contact should be used to short out
the paralleling CT secondary when that generator is not paralleled to the bus. If the switch is not
used, a voltage droop will be introduced into the system. This is due to the unloaded generator
parallel CT not supplying its compensating signal, but allowing a voltage drop to occur across it. Lack
of this shorting contact will also cause the voltage of the incoming generator to fluctuate prior to
paralleling. Ideally, this contact is an auxiliary on the circuit breaker contactor that opens when the
circuit breaker is closed.
b. For reactive differential compensation, connect each CT to its respective regulator. Then connect
the finish of the first CT to the start of the second CT, the finish of the second CT to the start of the
third CT, etc. Continue until all CT's are connected in series. The final step will be to connect the
finish of the last CT to the start of the first CT. (See Figure 3-6).
c. Reactive differential compensation cannot be used when paralleled with the utility or any infinite
bus. If this compensation system is used, a switching circuit must be used to convert the system to
a reactive droop compensation system. Contact the factory for additional information.
3-4. REACTIVE DROOP COMPENSATION (DROOP)
3-5. REACTIVE DIFFERENTIAL COMPENSATION (CROSS CURRENT)