Online re-dispatching of power systems based on modal sensitivity identification

Sensitivity approach has been widely used for various re-dispatching problems in power systems. The conventional sensitivity approach depends heavily on the detailed system model hence it suffers from the model bias problem. Existing sensitivity identification methods can indeed release the requirement of the system model, but the commonly-used constant sensitivity assumption is inconsistent with the actual situation. To solve this problem, this study proposes an online sensitivity identification method with the ability to track the system operating conditions. A general online re-dispatching procedure integrated with the proposed method is then introduced for various re-dispatching problems. Since the proposed method is data oriented and is comparable with the model-based method, it facilitates online implementation of the conventional sensitivity-based re-dispatching method. The key issue of the proposed approach, online sensitivity identification, is validated in a two-area four-machine system, compared with the conventional model-based method. Finally, the effectiveness of the whole re-dispatching procedure is demonstrated in a large complex system, China Southern Grid.