First of all, thank you for your response and suggestions.
I did try to zoom the signal with the scaling, but what I obtained didn't change (Picture 1). I also tried the other viewer, Time Series Visualizer SVG/d3, and at first what I obtained what the same, but when zooming I got a diagonal signal (Picture 2). This is why I don't see why I don't get oscillations in the Animated Time Series Visualizer, and also, don't know how to interpret the behavior of the model. I'm also going to add the parameters of the simulation cockpit (Pictures 3 and 4).
-Conduction speed: 10
-Local dynamic model: kuramoto oscillator
-Integration scheme: heun
-Integration step-size: 0,01220703125
-Sampling period: 0,9765625
-Simulation length: 10000,0
As for the phase plane, I did find it extremely useful when using other models. In this case, with the kuramoto oscillator model, there's just one model parameter and the phase plane is extremely simple, so it doesn't really help to adjust the value of the parameters (Picture 5).
Maybe I'm making a mistake and I can't see where, but I have tried different values in different simulations and don't know how to understand the results I am obtaining.