Strange power surges in home appliances

my appliance seem to have a kind of a fluctuation in power - in appliances like fridge and exhaust fan I can tel this by the normal operating sound getting softer and louder in a loop. light bulbs dim a bit and get brighter again, and it happens even with only one appliance on in the whole apartment.
The electricity doesn't trip all that often, but I would like to get this solved. Any advice?
Thanks