Parallel solution of transient stability constrained optimal power flow by exact optimality condition decomposition

Abstract

Power systems are required to achieve an optimally economic operating point while maintaining security and stability in the presence of credible contingencies. Transient stability constrained optimal power flow (TSCOPF) is a tool to bridge steady-state optimal power flow (OPF) with transient processes under a predefined set of simulated contingencies to guarantee post-fault rotor angle stability in a simulation time window. A parallel solution of TSCOPF using exact optimality condition (OC) decomposition is proposed, where generator swing equations are utilised recursively by exploring the structure of OCs of TSCOPF from the end of simulation time window to its beginning to derive an exact explicit expression consisting of generator-dynamics-related variables in terms of the steady-state variables. The OCs of the TSCOPF model are then decomposed into the OC of OPF, along with a parallel evaluation of this expression for each contingency. Multi-core processing units are applied to accelerate the evaluation process. Case studies with up to 1047 buses over 16 contingences demonstrate an 8× improvement in the computation for realistically sized power systems using the proposed decomposition strategy.