The purpose of the paper is to describe the ongoing work on methods and tools, reinforcing engineering confidence in several phases of the I&C systems design, including the verification of design implementation with regard to the upper level requirements, and the generation of tests. The first part of the paper will deal with a methodology to identify and formalize high-level requirements in the most generic way. The first steps of the methodology is based on a specification document analysis; it consists in identifying the studied system, its external systems, its main components, its operation modes and its requirements. These requirements are then formalized, before being modelled, simulated and analysed independently. Then, the requirements are simulated and analysed all together. Finally, the high-level requirements shall be coupled with lower-level requirements or production diagrams. The second part will describe the case used to implement the methodology, as well as the modeling tools. The use-case is the I&C part of electrical switchgears, which are pieces of equipment in conventional technology which interface I&C systems and actuators. STIMULUS (developed by ArgoSim) has been used for the high-level requirements and ControlBuild (developed by Dassault System) for the production diagrams. As a conclusion, the paper will describe what benefits the tool-base method provides to I&C Verification and Validation activities.