There are several options available in the Synchronous Machine for advanced users. All of these options are disabled by default, and are only invoked if the user so chooses.
D-axis Transfer Admit Data Available?: Real and imaginary parts of the D axis transfer admittance can be entered under the generator data format. Select if this data is available or not. This information is used to determine the leakage inductance between the field winding and the equivalent D axis damper winding. The model will estimate field leakage and resistance values based on the relevant time constants. However, the transfer admittance data is used to make the representation of the field winding characteristics more accurate. The transfer admittance data is obtained through the following test. See the paper by I. M. Canay, EMTDC references [14] for a detailed discussion. Keep the rotor 'locked' and apply a reduced voltage at the fundamental frequency to the stator windings. The rotor position is selected so that the q-axis armature voltage is zero. The current (in pu) in the shorted field winding is divided by the d-axis voltage (in pu) to get the 'transfer admittance'. The real and imaginary parts of this admittance should be entered under 'generator data format' of machine data input.
Force Currents = 0 at t = 0?: If the current is forced to zero, only the initial rotor mechanical angle (a saw-tooth wave passing from 0 to 2p radians every period of fundamental cycle) will be set and the initial machine currents will be set to zero. This option is useful if the user wishes to bring the machine up from a de-energized condition, but with the correct rotor angle to fit into a desired load flow.
Control Source P out?: If enabled, when starting the machine as a voltage source at its terminals, the source phase angle will slowly be adjusted until the desired power is reached. The desired power is specified in the Variable Initialization Data section of the component properties as Initializing Real Power.
Control Machine P out?: If enabled, when starting as locked rotor, the rotor angle will slowly adjust until the desired power is reached. The desired power is specified in the Variable Initialization Data section of the component properties as Initializing Real Power.
Modify Mechanical Dynamics?: If enabled, when starting as a free running machine, its inertia constant can be adjusted dynamically. This is useful in rapid settling of electromechanical oscillations by dynamically lowering the inertia constant. When steady state is reached, the inertia constant can be returned to its normal value.
Accelerated Flux Build-Up at Start?: If enabled, machine flux build-up can be accelerated, which can bring the machine to steady state, particularly if field and armature currents are not in steady state condition. The way the acceleration is achieved in the machine model is to provide for multiplication of all rotor resistances and the field voltage by a factor. The factor can be enabled or disabled by the user under the Variable Initialization Data section of the component properties as Disable/Enable Ef Multiplication. The actual value of the multiplication factor is also defined under the Variable Initialization Data section of the component properties as Field Voltage Multiplier, whose default value has been entered as 1.0.