Print this page Introduction to Short Circuit Current Calculations
Velimir Lackovic, MScEE
Course Outline
Short-circuit studies are done to determine the magnitude of the prospective currents flowing throughout the power system at various time intervals after a fault occurs. The magnitude of the currents flowing through the power system after a fault varies with time until they reach a steady-state condition. The information is used to select fuses, breakers, and switchgear ratings in addition to setting protective relays.
This behaviour is due to system characteristics and dynamics. During this time, the protective system is called on to detect, interrupt, and isolate these faults. The duty imposed on this equipment is dependent upon the magnitude of the current, which is dependent on the time from fault inception. This is done for various types of faults (three phase, phase-to-phase, double-phase-to-ground, and phase-to-ground) at different locations throughout the system.
This course includes
a multiple choice quiz at the end,
Learning Objective
At the conclusion of this course, the student will:
- Fault analysis according to industry standards;
- Models of branch elements;
- Impedance diagram;
- System modeling and computational techniques;
- Extent of the model;
- Extent and requirements of short circuit current studies;
- Factors affecting accuracy of short-circuit studies;
- Computer solutions; and
- Practical example.
Intended Audience
This course is intended for electrical engineers.
Benefit to Attendees
Attendee of this course will be able to understand types and causes of faults in the electrical power system. Electrical equipment modeling and manual fault calculation procedure is shown in great detail. Also attendee will be able to independently perform suitable mitigation measures for reduction of the excessive fault currents.
Course Introduction
Short circuits cannot always be prevented so system designers can only try to mitigate their potentially damaging effects. Electrical system should be designed so that the occurrence of the short circuit becomes minimal.
One of the major parts of system protection is orientated towards short-circuit detection. Interrupting equipment at all voltage levels that is capable of withstanding the fault currents and isolating the faulted area requires considerable investments.
Course Content
In this lesson, you are required to download and study the following course content in PDF format:
Introduction to Short Circuit Current Calculations
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Course Summary
This course presented fundamental facts about calculating short circuit currents in the electrical power systems. Fault types are described and how these fault types are treated by various international standards. Important considerations about network equipment that need to be taken into account when calculating fault levels were mentioned. Basic conversion to per units was described for various electrical network elements. Two different calculation methods were demonstrated on the practical electrical system along with step by step calculation procedure.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
