You mentioned that you are using a solid state voltage stabiliser. These devices are designed to automatically switch between different taps on a transformer to comensate for changes on the input voltage. The issue you have may be that it is being operated out of its specified input range (e.g. they may be only designed to cope with voltage input ranging from say 200 to 260VAC). Try and find the specifications for the voltage stabiliser and see if it will cope with say 180V on the input (while still being able to convert the voltage to 220V)
Originally Posted by foto-r3
Your friend's suggestion is right, in that the voltage into your house WILL vary over a 24 hour period, it will increase at night time when less electrical load is on the distribution system. To solve this problem with an automatic solution is going to be expensive. Personally I would go for a manual option, and that is to buy a variac and an analog voltmeter. Get an electrician to permanently connect the voltmeter to the output of the variac so that you can manually adjust the voltage to be 220V whenever you need to (i.e. as it varies over the day). With this option you will also need to install an overvoltage cutout circuit (a.k.a. a crowbar circuit) which will prevent the voltage from going above say 230V.