4H-SiC has recently attracted significant attention as a next-generation power semiconductor material. One of the major issues of 4H-SiC is bipolar degradation, in which device performance gradually deteriorates during long-term operation under forward current. This degradation is attributed to the expansion of stacking faults caused by the glide of partial dislocations constituting the stacking faults. Therefore, elucidating the mechanism of stacking fault expansion is important. It is mainly attributed to two mechanisms: Quantum Well Action (QWA) and Recombination-Enhanced Dislocation Glide (REDG), where the stacking fault energy and the activation energy of dislocations decreases under carrier injections, respectively. Although the expansion behavior of stacking faults under carrier injection and thermal stress has been experimentally reported, the detailed mechanisms governing stacking fault expansion, as well as the time evolution of the expansion in numerical simulations, have not yet been fully clarified. Therefore, In this study, dislocation dynamics simulations were performed to investigate stacking fault expansion numerically by incorporating- both QWA and REDG model. The motion of partial dislocations was modeled based on dislocation theory, in our model, implementing QWA and REDG models by setting appropriate stacking-fault energies and activation energies for kink formation, respectively, which reproduces the conditions under carrier injections. Furthermore, introducing kinetic parameters enabled us to evaluate time evolutions of dislocation motion and stacking fault expansion. Using our developed modeling, we calculated We calculated stacking fault growth over parameter sweeps designed. We found that the expansion width of stacking fault increased as the stacking fault energy decreased, which corresponds to the case when current is flowing. Furthermore, we found that the expansion rate greatly increased when each dislocation has the activation energy calculated in the charged state. Therefore, we quantitatively identified when stacking fault expansion is promoted or suppressed, offering insight into SiC power device degradation.