Impact of fault level constraints on the economic operation of power systems

The aim of this paper is to prove that fault levels may have a significant impact on the economic operation of modern power systems. First, we present a simple method for the incorporation of fault level constraints (FLCs) in the optimal power flow (OPF), the main optimization tool for the economic operation of power systems. The constraints imposed by fault levels are converted to simple nonlinear (inequality) constraints, described by variables of the conventional OPF. Most common OPF-solving engines already have the computational capacity to handle numerous nonlinear constraints, such as the ones described by the power balance equations on buses. Therefore, once FLCs are converted to nonlinear constraints described by OPF variables, they can be directly introduced to any optimization process performing the OPF. We applied this enhanced OPF on a simple 12-bus network. The results verified the significant impact fault levels have on the optimum operating point of the power system.