Global Transient Stability-Constrained Optimal Power Flow using SIME sensitivity analysis

Abstract

This paper presents a new, importantly improved, approach to Global Transient Stability-Constrained Optimal Power Flow (TSC-OPF). The main practical difficulty of global TSC-OPF has always been the huge dimension of its resulting optimization problem, since all the different approaches of this type reported in the literature require discretizing and including part of the time-domain simulation as additional dynamic constraints, along with a large set of equations as stability constraints, in the Optimal Power Flow problem, so as to be able to take into account transient stability limits. In our previous research, information provided by the Single Machine Equivalent (SIME) method was successfully used to reduce the dimension of the set of transient stability constraints to a single equation, applied at an individual time step. In addition, the length of the time domain simulation included in the OPF problem was also objectively defined, thus reducing the dimension of the set of dynamic constraints. However diminished the size of the optimization problem, it has been found that it is still possible to reduce its dimension. In this paper, new findings using sensitivity analysis and dynamic information from the SIME method are presented which allow for significantly reducing the dimension of the set of dynamic constraints, by limiting the length of the time-domain simulation to be included in the global TSC-OPF to a single (initial) time step, improving in this way its practical application, solution feasibility and execution speed.