A hierarchical voltage-reactive power control scheme for a radial transmission system

A coordinated hierarchical control scheme for a long-distance radial transmission system is proposed. A tuning method of the control parameters of the primary and the secondary controllers is developed, using the well-known frequency response technique. A practical power system is used as an illustrative example for the proposed method. Simulation results confirm conclusively the validity of the design technique, and also show that the proposed coordinated hierarchical control scheme will improve system voltage stability as well as managing the reactive power resources in an equitable way.