This paper proposes a novel two-dimensional continuum model that aims to capture the electromechanical wave phenomenon observed in power systems after a disturbance. The model is derived by a homogenization process of the discrete parameters of the conventional, discrete transient analysis model. The implementation of the proposed model is detailed. The paper also demonstrates the accuracy of the proposed model by comparing its results with those obtained from the discrete model. It is observed that the proposed model is able to provide a similar characterization of system electromechanical dynamics as the discrete model from a continuum point of view.