Class 5 of 8: Transformer Protection: 87T Differential, Harmonic Restraint, REF and Backup. This self-paced class covers 87T percent differential TAP calculation, phase and zero-sequence compensation, slope and minimum pickup, harmonic restraint, REF, 24 V/Hz and transformer backup protection, plus a field walkthrough and a case study. It has about 45 minutes of lesson content plus video activities and a 30-question quiz. It is part of the SubstationU.com Protective Relaying Series, Intermediate Protective Relaying (Level 2 course). Continuing education credit: 0 (none awarded yet).

Read the lesson book and complete the video activities, then pass the 30-question quiz with 80% (24 of 30) or better; you can retake the quiz as many times as you need until you pass.

Class 5 of 8 in the Level 2 series, Intermediate Protective Relaying (PR-201 to PR-208). Recommended order: PR-201 through PR-209; classes may be taken in any order. Level 1 (PR-101 to PR-109) is recommended preparation.