Single phase Transformer face many issues like overheating,short circuit over long duration of working in industries.
It is impossible to inspect a pre-installed transformer for these types of operation defects regularly.To overcome this problem a High Power Protection Relay is used known as the Percentage Differential Relay.
The working of the percentage differential relay is very simple,it detects the current in the winding of the transformer if the winding current is increased beyond a certain stage it trips and isolates the transformer from the mains supply to protect it from burning.
The attached video is the operational panel for the Percentage Relay.
