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. In addition, an accurate assessment of these currents is also essential for determining the settings of the system protection devices. 

Electrical systems are subjected to several external & internal influences like weather conditions, lightning phenomenon, pollution, insulation failure, temperature rise, etc., these influences cause abnormal operational condition, which could lead to voltage and frequency variations and feeder trips, brown out or black out of electrical system, and sometimes, may lead to equipment damage or system failure.

Course Objectives

Upon completing this course, the learner will be able to meet these overall objectives:

• Understanding the Grounding System of Transmission and Distribution

• Networks and how it affects the electrical quantities, short circuit level and protection system

• Understanding the causes of Voltage Deviations and its effect on auxiliaries of industrial loads and the stability of Electrical Power Systems

• Knowing the reasons of the shortage of active and reactive power in electrical networks and its effect on the electrical quantities

• Understanding the effect of environmental conditions on the electrical equipment

• Understanding the abnormal phenomena, which affect the electrical networks.

Who Should Attend

The course curriculum is designed for Electrical Technicians, Supervisors, Foreman and Technicians involved in commissioning, operation, and protection of electric power systems.

Course Content

Module (01) Introduction to Fault Analysis

1.1 Source of Fault Current 

1.2 Fault Statistics 

1.3 Basic Assumptions 

1.4 Short-circuit rating of equipment 

1.5 Selecting the correct switchgear rating for fault duties 

1.6 Overview of Per-Unit System 

1.7 One-Line Diagrams 

Module (02) Three Phase Short Circuit Currents 

2.1 Manual calculation of three-phase short-circuit current 

2.2 Circuit reduction techniques 

2.3 Industrial systems 

2.4 Electricity supply systems 

2.5 Tutorial – based on attendees plant 

2.6 Cables subjected to short-circuit currents 

2.7 Compliance with regulations 

Module (03) Unsymmetrical Fault Conditions 

3.1 Overview of symmetrical components 

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 Fault diagrams 

4.2 Interconnected sequence networks 

4.3 Special considerations with reference to limitation of earth fault current 

4.4 Demonstration examples based on industrial power systems 

Module (05) Power Distribution Systems Isolation and Restoration Methods

5.1 Topology

5.2 Faults

5.3 Sensors and actuators

5.4 Size

5.5 Supply restoration

5.6 Position of the problem in the literature

5.7 Planning and related areas

5.8 Successive Reclosing Method

5.9 Tele control method

5.10 Testing device

5.11 Testing and results

Module (06) Short Circuit Calculations & Circuit Interruption

6.1 Three Phase Faults

6.2 Line to Line Faults

6.4 Line to ground Faults

6.5 Equivalents System Impedance

6.6 Current Limiting Inductors

6.7 Short Circuit Level

6.8 Effect of Induction Machines on Short Circuit Level

6.9 CB Rupture Capacity

6.10  Example of Short Circuit Calculations 

Module (07) Types of Earthing and Faults Current Level

7.1 Introduction

7.2 Selection of Grounding Method / System

7.4 Understanding Ground Resistance

7.5 Ground Resistance Value & Measurements 

7.6 Effect of type of earthing on fault Current Level

Module (08) Transmission Lines and Feeders Faults Analysis and Protective Relays

8.1 Transmission Lines Faults

8.2 Line to Ground Faults

8.3 Phase Faults

8.4 Transmission Line Protection

8.5 Directional – Non Directional – Over Current & Earth Fault Relays / Differential Relays

8.6 Male and False Operation Considerations

Module (09) Power Transformers Faults Analysis and Protective Relays

9.1 Types of Faults

9.2 Through Faults

9.3 Internal Faults

9.4 Phase Faults

9.5 Earth Faults

9.6 Tank faults

9.7 Gas Actuated Relays

9.10 Buchholz Relays

9.11 Electrical Relays, Differential, Restricted Earth 

9.12 Transformer with Ground Neutral