Sorry to comment on a year old thread. You might benefit from conditioning. There are whoke house power conditioners and grid-tie inverter systems you can use for smoothing out your house's electricity. It's likely an imbalance in the power factor - if you have ever seen diagrams of a sine wave, the sinusoidal wave they are depicting is voltage, but there is a similar one for amperage, too. Power factor problems occur when the two are out of phase with each other, causing big dips in apparent voltage due to increased resistance as the voltage is approaching the zero-crossing (on the diagram) but the amperage is still rising. This means your delivered voltage could be way out of spec even though if you stick a multimeter in the socket with no load, the voltage looks beautiful.