Operation of on load tap changer in transformers?

OLTC - INSTALLED IN THE PRIMARY SIDE OF A POWER TRANSFORMER TO SELECT OR ADJUST VOLTAGE. THE ADVANTAGE OF THIS IS FOR SOLVING THE VOLTAGE DROP ISSUES IN THE SECONDARY OUTPUT IN THE FARTHEST LOCATION. FOR EXAMPLE YOUR SECONDARY VOLTAGE REQUIREMENT IS 380 VOLTS AND YOU CAN ADJUST TO 400 VOLTS FOR LONG CABLE RUNS.