Da Italiano a Inglese Tecnico/Meccanico Elettronica/Elettrotecnica dati tecnici di potenza massima e minima di assetti e fasce di funzionamento

We're talking electrical tranmission grid here. I am translating fasce as "operation segments", as we are talking about parts of the grid owned by different operators. I have seen the word "trims" as a possible translation of "assetti", but can't find its usage anywhere but in automotive terms. Any suggestions? Thanks!