Course Overview

The course is concerned with the calculation of fault currents in practical electrical power systems. Short-circuit currents are associated with large amounts of very destructive energy and therefore calculations must be made to ensure that the short-circuit ratings of equipment are adequate to cater for these high currents. 

This course teaches practical electrical troubleshooting and is concerned with the calculation of fault currents in electrical power systems. Short-circuit currents are associated with large amounts of very destructive energy and therefore calculations must be made to ensure that the short-circuit ratings of equipment are adequate to cater for these high currents. Accurate assessment of these currents is also essential for determining the settings of the system protection devices.

Course Objectives

Upon completion of this course, the trainees will be aware and understanding of the following:

Ìø‰Û_å¤ Understand the various types of fault currents

Ìø‰Û_å¤ Determine the causes of overcurrent and short circuit current

Ìø‰Û_å¤ Explain differences between symmetrical and unsymmetrical faults

Ìø‰Û_å¤ Analyse the common faults in a power system

Ìø‰Û_å¤ Interpret manual calculation verses software aided fault current calculations

Ìø‰Û_å¤ Knowing the reasons of the shortage of active and reactive power in electrical networks and its effect on the electrical quantities

Ìø‰Û_å¤ Understanding the effect of environmental conditions on the electrical equipment

Ìø‰Û_å¤ Understanding the abnormal phenomena, which affect the electrical networks.

Who Should Attend

This course will benefit all levels of personnel in an electrical installation. It will enable them to identify the causes and apply analysis of electrical faults in a power system.

This course is suitable to a wide range of technical professionals but will greatly benefit:

• Electricians

• Electrical supervisors

• Plant electricians

• Operations & maintenance engineers, supervisors & technicians

• Maintenance technicians

Course Content

Module (01) Introduction to Fault Analysis

1.1 Source of fault current in an electrical installation

1.2 Common fault statistics of electrical equipment

1.3 Short-circuit rating of equipment

1.4 Selecting the correct switchgear rating for fault duties

1.5 Overview of per-unit system and one line diagrams

1.6 Sources of impedance data for all items of plant

Module (02) Three-Phase Short-Circuit Currents

2.1 Review – summary – discussion

2.2 Manual calculation of three-phase short-circuit current

2.3 Industrial systems and fault current analysis

2.4 Tutorial – based on attendees plant

2.5 Cables subjected to short-circuit currents

2.6 Compliance with regulations

Module (03) Unsymmetrical Fault Conditions

3.1 Overview of symmetrical components and faults

3.2 Consideration of various fault types

3.3 Sequence networks

3.4 Consideration of phase shift in two-winding transformers

3.5 Consideration of earth impedance

3.6 Consideration of three-winding transformers

Module (04) Representation of Unsymmetrical Faults in Power Systems

4.1 Review – summary – discussion

4.2 Fault diagrams of electrical equipment

4.3 Interconnected sequence networks

4.4 Special considerations with reference to limitation of earth fault current

4.5 Demonstration examples based on industrial power systems

4.6 Introduction to fault current analysis software

Module (05) Short Circuit Calculations & Circuit Interruption

5.1 Three Phase Faults

5.2 Line to Line Faults

5.3 Line to ground Faults

5.4 Equivalents System Impedance

5.5 Current Limiting Inductors

5.6 Short Circuit Level

5.7 Effect of Induction Machines on Short      Circuit Level

5.8 CB Rupture Capacity

5.9 Example of Short Circuit Calculations 

Module (06) Types of Earthing and Faults Current Level

6.1 Introduction

6.2 Selection of Grounding Method / System

6.3 Understanding Ground Resistance

6.4 Ground Resistance Value & Measurements 

6.5 Effect of type of earthing on fault Current Level

Module (07) Power Transformers Faults Analysis and Protective Relays

7.1 Types of Faults

7.2 Through Faults

7.3 Internal Faults

7.4 Phase Faults

7.5 Earth Faults

7.6 Tank faults

7.7 Gas Actuated Relays

7.8 Buchholz Relays

7.9 Electrical Relays, Differential, Restricted Earth 

7.10 Transformer with Ground Neutral

Module (08) Computer based Calculation of Faults

8.1 Introduction to a scaled down fault analysis software

8.2 Common network faults

8.3 Industrial standards namely ANSI, NEC & NFPA 70 compliance

8.4 Case studies of faults in a high voltage network

8.5 Case study of faults in a low voltage network