Uses the current entering and leaving the transformer to detect internal faults.

Paithankar uses the "graded time" method and the "discrimination by current" method with unmatched simplicity. He provides a table showing how to coordinate a downstream 0.2-second relay with an upstream 0.5-second relay.

You're looking for a piece (possibly a chapter or a portion) from the book "Power System Protection" by Paithankar.

A highly selective method used for transformers and generators. It compares the current entering and leaving a component; any difference indicates an internal fault. Rohini College Conclusion The work of Paithankar and Bhide