A generalized power-flow-based initialization method for electromagnetic transient simulation of renewable energy generation units

As renewable energy generation units become more integrated into power systems, electromagnetic transient (EMT) simulations have become essential for analyzing the dynamic behavior of grid-connected renewable energy systems. However, conventional zero-state initialization methods often fail to ensure a physically consistent steady-state operating point, leading to non-physical transients that degrade both simulation efficiency and accuracy. This paper proposes a power-flow-based initialization method for renewable energy generation units, which guarantees the provision of physically consistent initial values for both state and algebraic variables. Starting from a steady-state power-flow solution, the proposed method systematically initializes the electrical, mechanical, and controller states of renewable energy generation units, ensuring consistency between AC/DC-side variables and the steady-state operating point at the beginning of the simulation. The effectiveness of the method is validated through simulations involving doubly-fed induction generator (DFIG), permanent-magnet synchronous generator (PMSG), and photovoltaic (PV) generation units. The results demonstrate that the method effectively suppresses non-physical transients, improving both EMT simulation stability and computational efficiency.