Initialisation of Grid-Connected Wind Turbine Models in Power-System Simulations

This paper describes a method of initialising dynamic wind turbine models in power-system simulations. The method uses grid-status information to initialise the grid-connected wind turbine model. The goal is to start a power-system simulation in a stationary state, without unnecessary transient behaviour at the beginning of the simulation. Correct initialisation is necessary to reach quickly the steady state of the grid-connected wind turbine, before a real transient on the grid occurs. Consequently, the dynamic performance of the system can be independently and accurately evaluated. The method presented considers wind turbines with directly grid-connected induction generators, with constant or variable blade angle (passive stall control, blade angle control or active stall control). These aspects apply to both constant and variable speed wind turbines. The investigation is performed in the commercial dedicated power-system simulation-tool DIgSILENT. Attention is especially drawn to the initialisation of the non-electrical parts of the wind turbine. The suitability of this initialisation strategy is illustrated by an example.