A new scheme to solve the potential integrals of time domain integral equation (TDIE) for planar PEC scatterers in free space is presented. In this method self-term singularities of the potential integrals are numerically calculated. The method uses some selected points in the source and observation patches in TD-MoM solver to calculate the potential integrals. The numerical integration of the potential integrals is almost two times faster than other methods that extracted or canceled singularity of self-terms. Numerical results illustrate the accuracy and simulation time of the proposed technique.