The present disclosure discloses a UPS system configured in parallel configuration. The UPS system comprises a plurality of slave UPS units, a master UPS unit comprising a controller configured to identify number of operative slave UPS units from the plurality of slave UPS units when at least one slave UPS unit from the plurality of slave UPS units is inoperative and change operating voltage of the master UPS unit based on the identified number of operative slave UPS units. The UPS system further comprises at least one slave UPS unit from the plurality of slave UPS units comprising a controller configured to monitor the operating voltage of the master UPS unit to detect the change in the operating voltage, determine the number of operative slave UPS units, calculate a slave current for supplying to the load, and initiate the slave UPS unit to supply the slave current to the load.