What are the Relays in transformer?

There are many types of protection relays used in Transformers depend upon its construction, size, use etc.

They are

1. Buchholz relay for incipient faults like short ciruit,

winding temparature protection, oil temparature protection,

oil level protection, oil pressure protection, Pressure

relief valve (for oil filled transformers)

2. Differential protection

3. Thermal Protection

4. Earth fault protection

5. Over current protection

6. Over excitation protection(where OLTC is used) etc