| Model
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                         The utility bus type used in modeling the power flow simulation. When you choose a model, those fields which are unavailable are dimmed. 
                        
                            - Swing: A swing bus holds the bus voltage and angle constant. To do this there cannot be limits on the amount of MW or MVAR the swing machine can accept or provide.
 
                            - PV: Constant power, constant voltage utility. This is also known as a regulated utility. This model tries to hold a user-specified bus voltage within utility MVAR limits.
 
                            - PQG: Constant power, constant var utility. This is also known as an unregulated utility. This model holds the MVAR generation within given voltage limits.
 
                         
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                    | MW
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                         The utility output MW. This may be actual operating or a rated value. This applies only to a PV or PQG utility. 
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                    | MVAR
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                         The utility output MVAR. This is only used when the utility is a constant power, constant var (PQG) machine or when a PV utility MVAR limit has been reached and the machine automatically switches to PQG. 
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                    | MVAR Limits
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                         The minimum and maximum MVAR limits for a regulated utility (PV). The utility will switch to type PQG if these limits are violated. 
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                    | Ctrl kV PU
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                         The desired control voltage for a regulated utility (PV). The utility will try to control the voltage at the controlled bus to a given value. If the utility bus is the swing bus, this voltage serves as the reference voltage. The voltage is entered in per-unit. 
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                    | Ctrl Angle
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                         Controlled angle is used only when a utility is designated as a swing utility. The value is entered in degrees. 
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