Allen-Bradley 1407-CGCM-DLR, User Manual, Page: 199 / 268

Rockwell Automation Publication 1407-UM002B-EN-P - February 2019 199
CGCM-DLR Unit Math Models Appendix B
VAR/Power Factor
Controller The VAR/PF controller is a summing point type controller and creates the
outside loop of a two-loop system. This controller is implemented as a slow PI
type controller. The voltage regulator forms the inner loop and is implemented as
a fast PID controller.
The model of the CGCM-DLR VAR and power factor controller is shown in
Per-unit Block Diagram for VAR Controller and Per-unit Block Diagram for PF
Controller , respectively. Non-windup limit (V
CLMT
) is used for bounding the
VAR/PF controller output voltages (V
Q
and V
PF
).
Figure 61 - Per-unit Block Diagram for VAR Controller
Figure 62 - Per-unit Block Diagram for PF Controller
Limiters
Both the over-excitation limiter (OEL) and the under-excitation limiter (UEL)
in this implementation are of the summed limiter type as opposed to takeover
type.
Per-unit Block Diagram for Under-excitation Limiter shows the model of the
under-excitation limiter. The UEL creates the outer loop and the voltage
regulator creates the inner loop. The UEL uses a PI type controller.