Modern power systems are exposed to various operating conditions that affect the steady-state operation of the system. Several researchers focus on monitoring dynamic loads and their impact on short-term stability, considering factors such as planning, expansion, management, and system capacity through VQ sensitivity analysis, determining the most sensitive bus to reactive power variation. Determining short-term stability helps operators take predictive actions in case of changes in the system, such as the entry of induction machines. The present research is focused on establishing a stability index to evaluate the system’s stability in a short-term dynamic state by incorporating nonlinear dynamic loads, as in the case of induction motors. The behavior of the proposed dynamic index, which has been called the Novel Index Stability Index (NISV), has been evaluated in several scenarios considering the IEEE 14-bar system, where the performance of the index is verified and how, when varying different conditions of the nonlinear load in time, it presents unstable conditions when faced with changes of the same.