Simplified Simulation of Digital Controllers In Power System Dynamic Studies

Time-domain simulation of power system dynamics requires solving large, sparse systems of nonlinear, stiff differential-algebraic equations. Traditional simulation tools have primarily emphasized solution accuracy; however, in the presence of digital controllers, such simulations remain computationally intensive as they must handle many discontinuities. In many practical applications, obtaining an approximate system response from the detailed model is sufficient, reducing the need for fullscale, high-fidelity simulations using small time steps. Simplified simulations provide a means to capture system dynamics quickly. However, the numerous discontinuities arising from the operation of digital controllers can become problematic for a simplified simulation, leading to significant inaccuracies and even divergence of the solver. This paper proposes a simplified simulation method suitable for power systems controlled by digital controllers, aiming to mitigate the accuracy loss of simplified simulation in the presence of multiple controllers.