Here it's really bad in the summer, due to the heat everyone has the A/C on, the population triples so the demand of the elec is high, the result was the sound would go off. The things I did to help was a dedicated spur, which doesn't really help, but keeps everything else of that line and the add a regenerator, not a conditioner as such but at regenerator AC>DC>AC, doing this Ive found helps stabilise the sound a bit better throughout the day.