Here is a basic illustration of a distribution system:
In a 3-phase AC system, phases cancel each other out, leaving only a small imbalance current and this is fed to earth at the substation. That is why when we touch neutral it is safe. I can understand up to this point.
Below is a transformer at a 3-phase system:
Here is my question:
Imagine some engineers set the electricity distribution such that it is balanced perfectly. Which means all the phases passes the same amount of current and no current flows from the balanced point to the earth.
But lets say one of the phases started to draw more current than the others, would the system now automatically balance itself by letting currents flowing from the balanced point? This is what I learned if I'm not wrong.
Is there an extra system which limits the current ratios?
I'm wondering whether there is an extra system to keep the three phase currents similar besides earthing the balanced point at the substation.