Protection Engineering And Research Laboratories

Advanced
Overcurrent Protection

2 Days

Pre-Requisites

To be effective the minimum pre- requisite for this course is a graduate electrical engineering degree or diploma. Participants with ITI certification must have at least two years of relevant work experience to enable easy learning in this course.

Objectives

This course will help electrical engineers to apply directional and non-directional over current relays to protect power system equipment. Participants of this course will gain knowledge to select the correct type of over-current & earth fault protection, calculate the settings to be adopted and to specify the optimum current transformers. The course will also provide them with knowledge required to find solutions for challenging situations in the field.

Course Outline

Fundamental Concepts

  • Various elements of power system
  • Operating states of the power system
  • Building blocks of protection system
  • Vital properties of a protection system
  • Zones of protection
  • Main and back-up protection
  • Monitoring of protection system

Basic Fault Calculation

  • Types of faults
  • Single-phase and three-phase fault
  • Building blocks of protection system calculations
  • Per unit calculation method
  • Worked examples for fault calculations

Instrument Transformers

  • Types of current transformers
  • Effect of current transformer core and winding design on its performance
  • Causes of errors in current transformers
  • Reasons for saturation of current transformers and its effect on protection
  • Specification of current transformers used for protection and metering applications
  • Types of voltage transformers
  • Specifying voltage transformers for protection and metering applications
  • Various methods of connection of voltage transformers and their application

Generator Protection

  • Types of faults possible in synchronous generator
  • Protections for detecting phase-phase, phase-ground and inter-turn faults in stator winding
  • Earth fault protection of rotor windings
  • Loss of excitation protection
  • Principle for detecting loss of prime mover and its setting for various types of prime movers
  • Operating principle of protection for detecting abnormal operating conditions of generators
  • Principle of backup protection of generators against uncleared system faults

Transformer Protection

  • Types of 3-phase transformer connections
  • Fault current distribution in 3-phase transformers
  • Types of faults in transformers
  • Transformer differential protection
  • Restricted EF protection for star and delta winding
  • Backup OC and EF protection
  • Ancillary protection of transformers

Induction Motor Protection

  • Characteristics of induction motors
  • Thermal overload protection of motors
  • Locked rotor and stalling protection
  • Supply voltage unbalance protection
  • Short circuit protection
  • Short circuit protection