On Line Stabilization of the large HV-AC-DC Power System BY Using Observation Decoupled Reference as a System-Wide Target

The concept of the Observation Decoupled Reference vector was introduced earlier [1] by the Washington University research group. It was demonstrated [2] [3] that effective system stabilization can be accomplished based on this new concept using purely local information and local action at the generating stations provided control means such as damping resistors or load skipping are available at each generating station. In this paper the Observation Decoupled Reference vector is considered as a systemwide target to be tracked and approached using a limited number of contr-l devices such as the converter terminals of an overlying HV-DC system. The tradeoff is that fast reliable communication between the generating stations and the Control Center are needed. Computations of moderate size are carried out both at the local units and at the Control Center. Very effective system stabilization is demonstrated by large scale simulation. It is believed that this represents the first real solution for using the (multiterminal) HV-DC system to stabilize an associated AC system.