Step voltage regulator

The RVR type feeder automatic voltage regulator is actually a single phase oil immersed auto-transformer with RWK controller and gathering sampling of voltage &current signal, on load tap charger controlling device to achieve gird more efficient from adjust the load character by increase and decrease the voltage. 
So This RVR is a transformer equipped with on load tap charger with RWK controller sampling voltage and current data and on load tap charger steps from current transformer and voltage transformer and limit switches.