Allen-Bradley 1407-CGCM, User Manual, Page: 46 / 252

Rockwell Automation Publication 1407-UM001H-EN-P - November 2014
#HAPTER CGCM Unit Operation
To activate droop:
•
the metering CTs and generator VTs must be properly connected and
configured.
•
the desired droop setpoint must be written to the V_DroopSetpt tag.
•
excitation enabled (tag SoftwareExcEn = 1).
•
remote Excitation Enable On (discrete input).
•
the CGCM unit must be in AVR mode (tag AVR_FCR_Select = 0).
•
droop must be enabled ( V_DroopEn tag = 1).
•
droop must be selected ( Droop_CCC_Select tag = 0).
•
automatic reactive power control must be disabled (tag PF_VAR_En = 0).
#ROSSCURRENT#OMPENSATION
Cross-current compensation (reactive differential compensation) is a method of
connecting multiple generators in parallel to share reactive load. Cross-current
compensation requires the connection of an additional CT into the cross-current
compensation input. The CGCM unit operates in a stand-alone application
without the cross-current inputs connected.
The cross-current compensation method of reactive load sharing is possible with
other controllers of similar type. Cross-current compensation monitors the ID
current, V GEN A, and V GEN C inputs to adjust the excitation level. A gain
adjustment is provided to allow tuning of the cross current control. Cross-current
compensation is configured and controlled by using the software interface to the
Logix controller.
To activate cross-current compensation:
•
the generators must be connected in parallel.
•
the cross-current CT and generator VTs must be properly connected.
•
the desired cross-current gain must be written to the CrossCurrentGain
tag.
•
excitation enabled (tag SoftwareExcEn = 1).
•
remote Excitation Enable On (discrete input).
•
the CGCM unit must be in AVR mode
(tag
AVR_FCR Select = 0).
•
droop must be enabled ( V_DroopEn tag = 1).
•
cross-current compensation must be selected ( Droop_CCC_Select tag
= 1) (and KVAR_LS_En tag = 1 for firmware rev. 2.
x
).
When cross-current compensation is disabled or control power is removed from
the unit, the cross-current input terminals ID(+) and ID(-) are internally
connected together through a very small impedance.
(1)
(1) For series B devices, the input terminals are not connected together when control power is removed.