University of Minnesota
University of Minnesota


Power System Protection

Course Learning Objectives 

  • Describe role of main, back up and redundant relay protection scheme
  • Identify zones of protection for a given substation or system
  • Select proper instrument transformer inputs to the relaying schemes
  • Analyze and calculate fault currents in a system for various types
  • Model power system equipment in fault programs
  • Develop a metering and relaying diagram for a substation showing instrument transformer connections, zones of protection, redundany and isolation for faults within these zones
  • Set relays – both high impedance and low impedance protection relays to protect power system buses
  • Set relays for Power transformer protection.
  • Select fuses or Set relays for the protection of distribution feeders
  • Set relays for the protection of shunt reactors and shunt capacitors
  • Select proper protection functions for the protection of generators and motor
  • Describe auto restoration methods- Auto reclosing, when to use high speed auto reclose and when to use synchronism checks for restoration

Course Description 

Lectures cover theory and practical application techniques available in the industry for the protection of power system equipment. Books available free online, IEEE application guides and published papers are used in the preparation of the presentations.
This is an introductory course introducing power system protection concepts.
Each session covers the following topics: Note: Each topic has one or more modules of half an hour duration.

  1. Fundamentals of protection – Zones of protection, security, selectivity and reliability, measurement principles – unit and non-unit protection, legacy relays, solid state and numerical relays
  2. Instrument Transformers Classification; dynamic response of CTs and CCVTs during faults and its effect on relaying
  3. Mathematical tools- Fault Analysis Symmetrical components – modeling of power system components such as transformers, generators, transmission lines, shunt VAR devices; fault analysis
  4. Bus Protection – Bus configurations; High and low impedance protection concepts. External Fault detection methods and remedial measures to account for CT saturation detection available in the industry. Relay setting examples and discussions on analysis of relay misoperations.
  5. Transformer protection – Inrush phenomenon, Inrush detection methods available in the industry; Differential and overcurrent/ over-excitation protection. Transformer protection setting examples. Relay setting examples and discussions on analysis of relay misoperations
  6. Transmission line Protection–Distance and non-distance based protection concepts. Zones and back up protection
  7. Applications of distance relays – pilot schemes, out of step relaying. Protection coordination
  8. Shunt reactor and Shunt capacitor protection –Configuration, Differential current and voltage schemes. Special considerations on capacitor grounding and switching devices. Relay setting examples
  9. Distribution system protection and system restoration – Feeder protection philosophies, . Coordination examples. Power system restoration concepts – Reclosing, Automatic sectionalizing
  10. Rotating Machinery Protection- Motor and generator protection; Discussion on generator construction and grounding methods; Detection of faults and abnormal operating conditions; Discussions of various relaying methods. Discussions on general protection methods of induction and synchronous motors; Setting examples

Slides for Video Clips 

Course Video Clips 

Online Homework Problems 

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