The goal of the thesis is to design and implement a multiplatform GUI tool, that will allow modelling of extended deployment and sequence UML diagrams. These diagrams will be able to capture the smart grid infrastructure together with usage scenarios in order to evaluate their reliability. The diagrams will be extended with multiple annotations which can be used by the tool to generate the formal model based on the stochastic reward networks. The generated formal model will be compatible and executable with the SPNP tool. Additionally, the thesis will also contribute to the implementation of a module for generic stochastic reward network model generation and transformation which will be utilized by the main tool. The tool will be implemented in Java.