A demand power factor-based approach for finding the maximum loading point

This paper presents a demand power factor-based approach (DPFA) for finding the maximum loading point (MLP) of a power system using the optimal power flow (OPF). In almost all the presented models in the literature two major drawbacks are obvious: (1) the active and reactive power demands increase equally, constantly, or at the same rate, while in the real world, this hardly ever occurs, and (2) the lack of consideration or misinterpretation of the demand power factor (DPF). This paper addresses the existing drawbacks by proposing a model based on a desired DPF, a threshold predefined by the independent system operator (ISO) that each consumer must maintain to prevent a surcharge. In the proposed DPFA, the active and reactive demands may increase differently resulting in: (1) providing a flexible loading pattern to find the best possible MLP, (2) keeping the desired DPFs at all load buses, and (3) improving the computational efficiency. To verify the DPFA, which is solvable via commercial solvers, several cases such as IEEE 14-, 30-, modified 30-, and 118-bus systems, and a large-scale 2338-bus system are conducted. Results confirm the potential, effectiveness, and superiority of the DPFA compared to the models in the literature.