In this paper, a fast and effective maximum loading point (MLP) calculation method is presented. This calculation process is based on the properties of the normal vector to the feasibility boundary computed close to MLP, which is calculated through a load flow method with step size optimization (LFSSO). The process is characterized by obtaining consecutive approximations of the MLP within the unfeasible region. Since the feasibility boundary contour in the neighborhood of the MLP may be non convex, some of the computed approximations may fall within the feasible region. Thus, a mechanism based on binary search is used to drive the operating point back to the infeasible region. Reactive power generation limits are taken into account. The MLP is accurately obtained after just a few steps, demonstrating the efficiency of the proposed method. Also, other load curtailment methods are studied and compared with the proposed method. The proposed formulation requires the same information (normal vector, power mismatches) and results in a better convergence path towards MLP. Simulation results for IEEE test systems are shown to validate the proposed method. © 2008 IEEE.