Long Term Voltage Stability Enhancement Using Direct Dynamic Optimization Method

This paper presents a direct dynamic optimization strategy to enhance long term voltage stability. Based on the Quasi-steady-state model, the coordinated voltage control problem is described by a differential-algebraic optimization form. The optimization problem including differential-algebraic equations is then converted into a nonlinear programming model by approximating state variable, algebraic variable and control variable profiles based on a family of polynomials on finite time elements. Primal-dual interior point method is applied to solve this nonlinear programming model. A line search filter method is employed to calculate the Newton step while permutation methods are applied to enhance the computational performance for solution of the correction equations. The simulation results on IEEE 17-machine 162-bus system show that the proposed approach can determine effective controls and largely enhance long-term voltage stability of power systems.