Power System Protection

Information to download CT saturation calculator

CT saturation calculator spreadsheet is available from Relaying Committee website under knowledge base. The link is  http://www.pes-psrc.org/kb/published/reports.html. Please download from "I-subcommittee report -2003-CT saturation Calculator", a zipped file. This will be used during lectures to show the effects of CT saturation.

GE Protection Automation Appication guide

Alstom called this: Network Automation Protection Guide (NPAG).

The protection book link provided in the Video is outdated as GE took over Alstom company. 

The book details are: Protection & Automation Application Guide (click here

Anyone who needs a soft copy can register and download. Here are the details:

Protection & Automation Application Guide

GE’s well respected Protection and Automation Application Guide, formerly known as the Network Protection and Automation Guide (NPAG), is a comprehensive 500 page technical reference that offers protection engineers and technicians the latest information and advice on protective relays, measurement and control, including in-depth application spotlights, typical applications with one-line diagrams, product selector guides, and technical brochures for GE’s protection and control products and services.

The Protection and Automation Application Guide has been popular with protection engineers and technicians since 1966 and also has served as a key reference for the international delegates at GE’s Annual Application and Protection of Power Systems (APPS) training courses, which GE has been running for more than 50 years.

Please click here to download a copy using your GE passport login.

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.
  • Fundamentals of protection – Zones of protection, security, selectivity and reliability, measurement principles – unit and non-unit protection, legacy relays, solid state and numerical relays
  • Instrument Transformers Classification; dynamic response of CTs and CCVTs during faults and its effect on relaying
  • Mathematical tools- Fault Analysis Symmetrical components – modeling of power system components such as transformers, generators, transmission lines, shunt VAR devices; fault analysis
  • 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.
  • 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
  • Transmission line Protection–Distance and non-distance based protection concepts. Zones and back up protection
  • Applications of distance relays – pilot schemes, out of step relaying. Protection coordination
  • Shunt reactor and Shunt capacitor protection –Configuration, Differential current and voltage schemes. Special considerations on capacitor grounding and switching devices. Relay setting examples
  • Distribution system protection and system restoration – Feeder protection philosophies, . Coordination examples. Power system restoration concepts – Reclosing, Automatic sectionalizing
  • 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

Course Slides

Homework Problems

Problems (Google Drive Link)

Power Systems

Electric Power systems Electricity MarketsPower Generation Operation and Control

Power System Protection Advanced Power Systems 1&2 HVDC