Optimal coordinated voltage control to enhance long term voltage stability using direct dynamic optimization

This paper presents the prototype of a direct dynamic optimization strategy to enhance the long term voltage stability. Based on the Quasi-steady-state model, the coordinated voltage control problem is presented by a differential-algebra optimization form. The dynamic optimization problem is transferred to a nonlinear programming model by approximating state variable, algebraic variable and control variable profiles based on a family of polynomials on finite time elements. Nonlinear primal-dual interior point method is applied to solve this nonlinear programming model. Filter line search method is used to compute the search step coupling with the Newton directions, larger steps may be accepted while the iteration approaches to the solution. This integrated strategy is tested on New England 10 generator 39 bus system and the simulation results show the potential for further extension on large scale optimization problems.