The smart grid is a complex and interconnected system where actions and events in one part of the system affect operations elsewhere. In order to perform a rigorous analysis, a common and deterministic timing reference is required. This paper addresses this need, using as use case the substation automation system, a key element of the smart grid, where utilities, classically, have opted for a satellite clock providing a timing signal and different ways to distribute it through the substation. This paper proposes an appropriate solution for the substation needs presenting the implementation details, the analysis of the system reliability, safety, and security together with promising results and novel mechanisms for providing timing on the grid.