Theoretical investigations based on the Ginzburg‐Landau theory and the consideration of the lifetime of normal particles and superparticles yields a new acceleration equation of superparticles and a diffusion‐type equation for normal current in nonequilibrium superconductors. Derived relations are used to examine the experiments on normal‐current injection in supernormal junctions and on the effective capacitance in superconducting microbridges. Good agreement is found between theory and experiment.