Why is an AVR important in areas with an unstable grid?

In many areas, especially at the far end of distribution lines, on islands, in rural areas or near industrial loads, the voltage does not stay close to the nominal 230 V. It may drop noticeably at peak hours or rise at night when consumption falls. An AVRGlossary · Power qualityAutomatic Voltage Regulator (AVR)A device that automatically maintains a constant voltage level to protect electrical equipment from fluctuations. corrects these sustained deviations and delivers an output voltage close to nominal.

Low voltage is often more insidious than high voltage: motors in fridges, air conditioners and pumps draw more current, run hotter and wear out faster. High voltage stresses electronics and power supplies. In a UPS without AVR, every such deviation means a switch to battery, which is then discharged often and wears out early; this is why Line-Interactive UPS units include an AVR function.

Practical tip: if you notice flickering lights, devices shutting down without warning or a UPS that often switches to battery, ask an electrician to measure the voltage at different times of day. Remember that an AVR does not cover power outages; for that you need a UPS. A common mistake is assuming that a power strip with surge protection does the same job as an AVR, when it only protects against momentary voltage spikes.