Cascaded state control for dynamic power conditioning in wind parks

The stochastic fluctuating offer of wind energy limits the capacity of supply in electrical grids by means of technical and economical reasons. To increase the supply, a concept of dynamic conditioning with the objective to increase the quality of supply was developed. The concept envisages support and management of the electrical grid respectively through compensation of active and reactive power with static converters (“Electronic Synchronous Machine”) and short time storage. By the four-quadrant operation of the converters, short time fluctuation of the energy sources and changes of the load can be absorbed or smoothed directly on location. By the use of dynamic storage systems an intermediate storage of the stochastic offered primary energy is done. This low order energy can thereby be converted into high order recallable energy, which even can be used to satisfy peak demands. The local compensation of the fluctuation of the energy supply on the one hand and of the changes of the demand on the other hand, allows a more steady energy demand from the nation-wide electrical grid. For this purpose a novel cascaded PI-state control, which a load dependent adaption of the control structure enables was developed and tested.