Table of Contents

Variable Speed Generator

Bladed supports the existence of a variable speed generator. This type is commonly used in modern turbines. A more detailed introduction can be found in the relevant [theory section].

Input Parameters

The variable speed generator requires a set of parameters to be given. The following properties can be specified using the input file:

  • GeneratorTimeConstant: The time constant \(\tau_e\) of the first order response of the generator. This defines the reaction of the generator to a change in demanded torque. This is given in \(s\) and has no default value. Choosing a very small number results in small time steps during the simulation. An instantaneous reaction (using a value of \(0\)) can possibly disable these very small time steps without sacrificing accuracy.
  • PowerFactor: The power factor of the generator, the cosine of the phase angle between voltage and current. This dimensionless value defaults to \(1.0\), if not specified.
  • MaximumTorqueDemand: The upper limit of torque demand possible for this generator. This value is given in \(Nm\) and has no default value.
  • MinimumTorqueDemand: The minimal torque demand for this generator. This defines the lower limit of possible torque for this generator (given in \(Nm\)). This value defaults to zero, if not specified.
  • GeneratorInertia: The total rotational inertia (given in \(kg\text{rad}^2\)) of the generator. This includes the inertia of the high-speed shaft after the clutch. This value cannot be omitted.
  • Losses: A definition of the losses between demanded power and output power. See Electrical Losses for more details.

An example for a possible generator is shown below. This generator has a linear model for electrical losses and a time constant of \(0.1\) seconds.

"VariableSpeedGenerator": {
    "GeneratorTimeConstant": 0.1,
    "PowerFactor": 0.95,
    "MaximumTorqueDemand": 100000.0,
    "MinimumTorqueDemand": 0.0,
    "ComponentType": "VariableSpeedGenerator",
    "GeneratorInertia": 550.0,
    "Losses": {
        "PowerLossAtNoLoad": 0.0,
        "Efficiency": 92.5,
        "ElectricalLossesType": "LinearElectricalLosses"
    }
}