The Irish power system illustrates today the main issues which many power systems need to address from an operations and control viewpoint, i.e. the advent of stochastic generation in the form of wind, solar and wave energy, and the change in the constitution of the electrical loads. This paper examines RoCoF standards and protection and presents a practical example of testing the RoCoF capabilities of on-load generators in a live pumped storage hydro station. The technical reasons and mathematical basis for carrying out these tests are included to provide context to the example described. Results for each test are provided with illustrative plots for reference.