Generator dynamics in a snapshot

System dynamic studies are very often used for relay setting. In this case, engineers are mostly interested to the maximum fault clearing time (MFCT) related to faults at different locations. Normally for every fault location, several runs of dynamic stability programs are necessary to identify the MFCT. The paper shows a different way of presenting the results of dynamic stability studies of power systems, valid for simplified models, to show a "snapshot" of all the possible dynamics. Using the approach of dynamic system analysis, the transient of a generator following a fault is represented as a trajectory in the phase-plane defined by its angle and speed. With such a representation if is easy to perceive at a glance the overall generator behaviour. In a single snapshot the behaviour of the machine is shown for all the external variations, like the fault duration or position. Small, on paper, b/w, printings offer a vary poor effect with respect to the same results on the PC screen.