The paper presents the result of an extensive study of several typical power systems to explore a fast decoupled load flow (FDLF) model that can exhibit the best convergence property for both well-behaved and ill-conditioned systems. An attempt has been made to examine the relative importance of several parameters, such as line series resistances, shunt reactances and transformer tappings, in the formulation of B′ and B″, on the convergence of the FDLF of Stott and Alsac [1]. Results reveal that a reverse Stott model achieves more or less the best convergence of the FDLF solution, irrespective of whether the systems are well-behaved or ill-conditioned. Amongst the parameters considered in forming [B′] and [B″], the resistance parameter plays the most significant role in the convergence of the FDLF solution, and not the shunts.