It’s possible to do LV and MV AC simulation?
I mean, similar to software like:
digisilent
DOCWin
XLpro² Calcul
Simaris Design 5.0
MyEcodial L 3.4
Caneco BT 5.3
I am not familiar with that software, and there is also some ambiguity about those voltage classifications. According to Wikipedia “medium voltage” is between 2kV and 33kV (Yes, that’s kilo Volts). 
I don’t use ngSpice much, but for a simulator it’s just dealing with floating point numbers, and those have a wider range then any physical unit
There may be people here who are familiar both with ngSpice in KiCad, and with the software you mention, but if you give a brief explanation of specific features you are looking for, you probably get a better answer.
I looked up the first link and it is power systems. So, yeah, probably NOT a Kicad question. I guess you could model the system in Kicad but probably not the best tool.
Does ngSpice care? That I don’t know.
Have you tried QSPICE?
I wish to make a 400kw 60hz 220v / 380v single line diagram with transformer 12.3kv feed, then make a simulation, then make a report with ferromagnetic and differential selection report (ABB, SIEMENS, SCHNEIDER switches).
Single line diagram will probably not work, also symbols should have all required pins (for example have a look at the transmission line symbols).
After some simple testing results were really close to powerfactory SW, tested in a trial version, for simple schematics. It requires more work to prepare the models though.