An evolutionary computation technique is used to minimize the active power losses, subjected to voltage constraints. The formulation is proved in two power systems, controlling variables such as generation voltages, taps position, and shunt elements, showing a reduction not only on power system losses but also resulting in a power generation decrement. These results are used to analyze the impact on the power system voltage stability. Results illustrate that in some cases even with losses' reduction, there is a negative impact on stability, since sometimes a reduction of saddle node bifurcation (SNB) are presented and therefore the system loadability is reduced as well. Special care should be taken into account if the system presents Hopf bifurcations (HB) because if the optimization technique impact negatively, then the operating point could reach the HB point with the possibility of a voltage collapse.