Smart Grid Initiative aims to use the current energy resources more efficiently by providing a more resilient and reliable infrastructure. One of the main targets of this initiative is the increased customer participation and interaction with the overall grid. In this paper, we analyse the customer domain in order to increase the understanding of this domain within smart grid and to investigate the tasks designated to this domain in detail. The analysis outlined in this paper includes the modeling of the system by using UML diagrams such as component and use case diagrams as well as use case scenarios that elaborate the actions performed by various entitities within the customer domain. The design and modelling efforts presented in this paper aim at providing means to obtain greater confidence in smart grid through domain analysis.