Enhancement of voltage stability conditions in system operation through an optimisation model

This work deals with the reinforcement of static conditions of voltage stability through a change in the operating point, using an optimisation algorithm as the computational tool. One test with the Brazilian N/NE system shows an operating point where the relationship between generated reactive power and terminal voltage of a static compensator is unusual, i.e. operation in the lower half of the V×Q curve. The proposed method calculated a new voltage set point and operation "moved" to the upper part of the curve. Another test, minutes before a major blackout in the S/SE systems presented the same inverted relationship between V and Q. The enhancement control action was based in voltage profile changes as well as active power redispatch