Transient Stability Augmentation using A Hierarchical Control Structure

A two-level hierarchical control structure for augmenting bulk system transient stabilitiy is described. This structure involves localized subsystem controllers communicating control value demands to an area coordinator. The local controllers, making computations in parallel, use locally available measurements to determine the present state in a. modified Zaborszky-Subramanian local equilibrium frame. The Barnard optimal aim strategy is then used to map this state point into a desired control value. This control value from each local controller is communicated to an area coordinator which allocates physical control means under its jurisdiction to optimally implement these demands. This paper deals primarily with the design of the local controllers. The. functional requirements for the area coordinator are also described. Experimental results, using the presented concepts obtained on the New England 10-machine test system, are also included These results indicate that substantial augmentation of transient stability margins can be achieved.