The calculation of the inertia constant in systems with a large number of synchronous machines is a complex process. That is why, in the event of a disturbance, it is interesting to take into account only those machines that are affected. For this purpose, it is necessary to analyse the dynamic response of the system to a permanent disturbance at a network node. From this, it would be possible to define a radius of affectation that would allow to know which are the machines that must be taken into account when calculating the inertia constant of the system as a whole. This master thesis demonstrates how it is possible to predict the dynamic response of the sys- tem in order to avoid performing dynamic simulations. This is achieved using Synchronizing Power Coefficients, and all analyses are performed using MATLAB and Simulink