Dynamic Power Flow Modeling Primary and Secondary Frequency Regulations

In power systems, the steady-state operations following any disturbance can be assessed by means of time-domain simulations, which consider the dynamic of the system without simplifying hypotheses. This paper proposes a formulation of the power flow problem with distributed slack bus model able to determine the steady-state impact on frequency and generation set-points of primary and secondary frequency regulation. This is done by deriving the real power balance expressions (including power losses, primary/secondary regulation, and the real frequency deviation) before and after the occurrence of any event or disturbance. This is achieved without resorting to the solution of a time-domain simulation. The performance of the proposed formulation is discussed through the standard WSCC 9-bus system and a 102-bus model of the Sicilian grid. Solutions are compared with those obtained with conventional time-domain simulations.