Protection & Relay Coordination

Duration : 3 Day

Course Purpose

The purpose of this course is to give exposure of substation protection relays and protection systems to all personnel working in the substation business unit of KEC.

This course is useful to understand the importance of protection systems and protection relay coordination for discrimination between faulty and healthy equipment

This course is also useful to have knowledge of various protection relays and instrument transformers, selection of relays by comparing advantages & limitations of various options.

The course is designed to develop the capability to select protection schemes for transformers, reactors, transmission lines and bus bars, to define settings for relays and have better relay coordination.


On completion of the course the participant will have fundamental knowledge of

  • Basics of protection relays and protection schemes
  • Numerical Relay and their functions/ characteristics
  • Instrument transformers
  • Relays for protection of transformers, reactors, transmission lines and bus bars
  • Philosophy of back up over current & earth fault protection
  • settings for relays to have better relay coordination
  • testing of protection relays to evaluate performance of protection system

Who should Attend

Design and Project Engineers with minimum 2 years experience.


  • Types of relays – Current operated, voltage operated and current and voltage operated Electromechanical & Numerical relays
  • Operating principle of numerical relays, functional elements and other features, connectivity of numerical relays with substation SCADA
  • Current transformers
  • Voltage transformers
  • Selection and sizing of CTs & PTs for protection schemes
  • Philosophy of over current & earth fault protection, definite minimum time and IDMT O/C and E/F relays
  • Transformer protection and recommended settings for functional elements
  • Reactor protection and recommended settings for functional elements
  • Transmission line protection, auto reclosing and recommended settings for functional elements
  • Bus bar protection of high and low impedance type
  • Parameterization of numerical relays
  • Relay coordination for discriminative operation
  • Relay testing by secondary injection method using relay testing kits