This paper proposes an efficient method that tunes wide-area power system stabilizers (WPSSs) to have probabilistic robustness for damping inter-area electro-mechanical oscillations in power systems with incorporated random wind power. Specifically, the efficiency of this method benefits from unique consideration and deduction of the analytic forms of cumulative distribution functions (cdfs) of two types of random variables and their derivatives with respect to tunable parameters of the conventionally structured WPSSs, based on approximations of wind power probability density functions by Gaussian mixtures. These cdfs then compose the objective function of an optimization that can rapidly solve for optimal parameters of WPSSs by a sequential quadratic programming algorithm. The optimized WPSSs are probabilistically robust because they enhance the probability of two commonly desired control effects. Simulation studies on a modified IEEE 10-machine and 39-bus system validate the superior efficiency of the proposed tuning method and the excellent performance of the derived WPSSs.

Aiming at the problem of broadband stability of voltage source converter based high voltage direct current (VSC-HVDC) system, a control strategy of converter is designed to improve its small signal stability. Based on the modeling of the flexible HVDC system, the overall structure of the internal and external loop control of the VSC-HVDC converter is established. DC control and AC control damping controller are designed respectively in phase locked loop and PI control. The state space equation of the control system is established to analyze its performance and design its parameters reasonably. The stability of small signal of the system is improved effectively through optimization of several links.