The size and complexity of modern power systems, as well as emergent technologies and the uncertainty in energy planning, make the design and engineering of these systems challenging. One of the main challenges is the development of models that adequately capture the complex relationships between the components of these systems. We present a DEVS (Discrete Event System Specification) based framework for modeling a power system for energy planning. DEVS preserves the hierarchical and modular construction properties of a system (Chow and Zeigler 1994). That is, it enables each of the components of the system to be modeled separately, as well as the representation of the multilayer architecture of that system. As a proof of concept, we present a power system model, simulating the deployment of energy sources, on the PyPDEVS platform (Van Tendeloo and Vangheluwe 2015), considering dispatcher, unit commitment, load, generation, storage and transmission lines components.