it is easy you should drive from frequency at point of common coupling

there are some good papers in IEEE, power delivery that mention about rocof and they simulated it

You can use simulation software for exampe DIgSILENT PowerFactory and run RMS simulation to get the curve of the change of frequency over the time .

You also have several good papers in which mathematical equations are given for such computation. Swinging curve equation need to be solved how df/dt can be calculated.

Srete

In the following paper, you will find a method for determining the ROCOF and estimation of the resultant inertia at any bus. In addition, some other issues are presented. The method is based on mathematical simulation of the hardware; however, it can be used directly from the hardware data loggers or monitoring systems after filtration processes.

https://www.researchgate.net/publication/276832443_Stability-based_minimization_of_load_shedding_in_weakly_interconnected_systems_for_real-time_applications?_sg=TsP3959To_o-Sw2IAqnqAqbXloMbul7UWm9rvjn5e-Xg01qdsk-jZ3OaJVVzDVoK-Szp1rTWvk9M5r62PB7FuG54ze2DqD0-ZhjTRufU.hp3nY6kIRe8_KQ0PylsVfrPsEjdOnEZ2k1mhnz6NtfvYjCHnas6rLAs6KW_CZoYTdsHhEAsk7IneEgeRWn3D4Q

I Think You Should See This Paper It Might Help You

Conference Paper A Study on Anti-Islanding Detection Algorithms for Grid-Tied...

In addition, in the following book, details of the estimation of the ROCOF and inertia are presented considering various models and controls of synchrounus generators used in traditional power generation.

https://www.researchgate.net/publication/307926879_Dynamic_Security_of_Interconnected_Electric_Power_Systems_-_Volume_2_Dynamics_and_stability_of_conventional_and_renewable_energy_systems

Equation can be found in chapter A of the paper:

" Performance analysis of the ROCOF and Vector Shift methods using a dynamic protection modelling approach"

Rafał Bugdał, Adam Dyśko, G.M. Burt, J.R. McDonald

University of Strathclyde

204 George Street, Glasgow G1 1XW

[email protected], [email protected]

Dear Imam

I have found excellent paper woith ROCOF model in MATLAB/SIMULINK.

https://www.researchgate.net/publication/265388851_Islanding_Prevention_Scheme_for_Grid-Connected_Photovoltaic_Systems_in_Matlab_Simulink

Srete

For islanding detection, sometimes RMS rate of change of voltage is used. We have used in one of our publications.