Rockwell Automation 1407-CGCM Combination Generator Control Module - Manual (Page 185)

Rockwell Automation Publication 1407-UM001G-EN-P - April 2013
185
Appendix
B
CGCM Unit Math Models
Introduction This appendix contains the mathematical model of the CGCM unit’s excitation
systems.
The rotating rectifier model is based on the type AC8B model available in the
reference Computer Models for Representation of Digital-Based Excitation
Systems in the IEEE Transactions on Energy Conversion September, 1996,
Vol. 11, No. 3. This paper was prepared by the Digital Excitation Task Force of
the Equipment Working Group, and jointly sponsored by the Performance and
Modeling Working Group of the Excitation System Subcommittee.
Synchronous Machine
Terminal Voltage
Transducer and Load
Compensator Model The CGCM unit implements the load compensation by using the vector sum of
the magnitudes of the terminal voltage and of the terminal current. The model
provided in IEEE Standard 421.5-1992 for terminal voltage transducers and load
compensators can be used to model this function in the CGCM unit’s system as
shown in the following equation.
Figure 59 - Terminal Voltage and Load Compensation Elements
The values used in this model can be derived from the CGCM settings as follows:
R
C
= 0 (Resistive load compensation not available)
X
C
= [1 - (1 - DRP/100))
2
]
1/2
T
R
= 5 ms
where DRP is the percent droop programmed into the CGCM unit, values range
from -30…30.
V
C1
abs V
T
R
C
 jX
C
I
T
+ +   =
V
T
I
T
1
1 T
R
s +
------------------
V
C1
V
C