A new method using energetic dynamic specifications, is proposed in this paper to study the stability of a cascaded electric system. To apply this method, a new modeling based on energetic variables, is introduced. Contrary to classical approach for which voltages and currents are the state variables, we propose to use electrostatic energies and powers as state variables. We will prove that with this approach the stability study, under some conditions, is few dependent of the operating point. Thus, the stability of large scale distributed system can be simplified if all the components of the system verify such properties. The proposed approach is verified with help of simulation results and experimental validation. © 2012 IEEE.