How do you control fluctuating power in rural home?

To control fluctuating power in a rural home I'm assuming you mean the power or lights dim out when certain electrical appliances come on. This fluctuation or dimming of the lights will sometimes occur when a well water pump kicks on, or the home AC starts, usually any major appliance that has a large amperage draw, even a household refrigerator. Typically the dimming of the lights is caused by too small of wires feeding the main electrical panel to the home. I would recommend having a licensed electrician look at the electrical service coming into your home.

Hope this helps some.