Formal verification of programs specified with signal: application to a power transformer station controller
Résumé
We present a formal specification and verification of the automatic circuit-breaking behavior of an electric power transformer station, using the synchronous approach to reactive real-time systems implemented by the data-flow language Signal. Synchronous languages have a mathematical model that supports the various phases of the development of a control system: specification, verification, simulation, code generation, and implementation. The complex hierarchical, state-based and preemptive behavior of the power station controller is specified in Signalgti, an extension of Signal with notions of time intervals and preemptive tasks. To validate the specification, a graphical simulator is generated using Signal's execution environment, and the required behaviour is proven to be satisfied, using its proof method.