An adequate integration of demand response programs requires the definition of distinct models covering a wide diversity of operation scenarios. In this paper, the proposed methodology addresses the definition of demand response programs considering the demand shifting between periods, in scenarios of multi-period demand response events. The optimization problem refers to the minimization of the operation costs for a Virtual Power Player in the energy resources schedule. Differential search algorithm has been used in order to obtain the solutions for the optimization problem in a large set of operation scenarios. The case study illustrates the use of the proposed methodology to support the decisions concerning the duration of each demand response event and considering the consumption shifting modeling as constraints of the optimization problem.