How can I model a P(V) controller to limit a generator’s active power?

Quasi-Dynamic Simulation

The objective is to limit the active power setpoint of a generator depending on the voltage measurement at its terminal. For this functionality, a QDSL-Model is attached to this ticket with the following behavior:

  • Limit Generators Pmax (maximum power infeed) dependent on the voltage
  • Pmax is limited based on generators nominal power or generators actual (time dependent) active power setpoint.
  • The slope of the power limiting curve is defined via the voltage ured and ulim as illustrated in the figure attached.


QDSL-Model description


  1. Input parameter

ured: voltage to start active power limiting

ulim: voltage to reduce active power to zero


  • mode = 1 to limit power based on nominal apparent active power rating
  • mode = 2 to limit power based on active power operational point

loopmax: Max. number of control loops to find the optimal set point


Connected network element: Generator to be limited by P(V) controller

Network element of input (QDSL models Load Flow page): Terminal for voltage measurement


  1. Description

The model will check in the outer loop of each Load Flow calculation, if the voltage is greater than the voltage ‘ured’. If this is the case and the voltage is less than ‘ulim’, the limitation will be set to:

Pmax = (Pact/(ured-ulim) * voltage) - (Pact/(ured-ulim)*ulim)

Where the minimum value of Pmax will be 0.

According to the mode (1 or 2), Pact will be set to Pnom (mode = 1) or the generator’s active power setpoint (mode =2).