Critical comparison of robust load flow methods for ill-conditioned systems

In this work, the performances of robust load flow methods are compared, in special when applied to ill-conditioned systems. In such cases, the iterative process may diverge or oscillate when standard Newton Raphson (SNR) based load flow calculation methods are used. Some known approaches to solve these systems are the Load Flow with Step Size Optimization (LFSSO) and Continuation Power Flow (CPF). Also, the Continuous Newton Power Flow (CNPF) method was proposed recently as a novel approach to solve ill-conditioned systems. Even though the performances of these methods have been reported in several sources, a critical comparison of the convergence characteristics and results for ill-conditioned systems are presented in this work. A modified version of the CNPF is also tested in order to improve its robustness. Simulation results for some IEEE test cases and realistic systems are shown to validate the analysis.