Trajectory Sensitivity Based Preventive Control of Voltage Instability Considering Load Uncertainties

This paper presents an application of the trajectory sensitivity method to the voltage stability problem considering load uncertainty. The trajectory sensitivity method can be used to determine the system stability bound based on the base case system response and the various load parameter sensitivities calculated along the base case. Based on the evaluated stability bound, the size of various preventive control actions to maintain system voltage stability will exist within a specific range instead of being a fixed amount. The trajectory sensitivity method is also utilized to determine the various optimal preventive control strategies in terms of shunt compensation and generation rescheduling, for all potential operating points that are deemed to be unstable. The computational efficiency problem is also addressed. A new Jacobian matrix updating strategy is developed for the very dishonest Newton (VDHN) method. Using this Jacobian updating mechanism, the computation time is significantly reduced. The proposed method is applied to a large WECC test system.