No load losses of the transformer

If you use superconducting coils, the efficiency will be of the order of 99.85%.

bioramani

If you use superconducting coils, the efficiency will be of the order of 99.85%.

And remaining 0.15% are because of the core we are using in transformer? I am not sure.

The no load losses are due to:
1. Hysteresis- In core laminations
2. Eddy current-In core laminations
3. Stray Eddy current- In core clamps, bolts and other components
4. Dielectric losses.
5. I2R losses-Due to no load current
Hysteresis losses and eddy current losses are the primary contributers (about 99%) of the no load losses.
Eddy current losses are reduced by using thinner and better quality of core steel and designing the core effeciently. Hysteresis losses are caused by molecules in the core laminations which resist getting magnetized and demagnetized by the alternating magnetic field. This resistance by molecules causes friction and heat is generated. Hystersis losses can be reduced by selection of proper size and type of core material.