[pjc50]

Note that the wavelength of 50Hz at 'c' is 6000km. There's not a lot of space to get very much out of phase and it will attenuate along the way.

The nearest I can think to "direction" is "reactive power", or the phase angle between voltage and current at any particular point.

There very definitely are loops and multiple paths to a particular point, it's not called a "grid" for nothing. This little map of the UK grid is interesting: https://www.nationalgrid.com/uk/about-grid/our-networks-and-...

Edit: Aha, further reading - systems for altering the phase angle: https://en.wikipedia.org/wiki/Quadrature_booster

And https://www.researchgate.net/publication/27341916_Influence_...

[theoh]

Along with quadrature boosters, there are (used to be?) these things, synchronous condensers: https://en.wikipedia.org/wiki/Synchronous_condenser

[_trampeltier]

But with 1500km it would be 90° out of phase and that would be already a pretty high voltage.

I'm also wondering since a couple of years about the same question.