Short Circuit Analysis of a Three-Phase HV System

Electrical power systems are often large, complex and sophisticated, always requiring specialized knowledge to be managed properly so that they are safe and yield optimum value to the end-users. These systems, no matter how good they are, cannot function without faults occurring from time to time. It is important that technicians and engineers who operate them have a good understanding of how they are manufactured to function, what regular maintenance should be carried out on them, how different fault types manifest and how they should be managed depending on the prevailing circumstances at the time of occurrence. This course focuses on faults and you will gain an understanding of the fundamentals of short circuit analysis. In order to examine high-voltage systems, you will be taught electrical circuit fault types such as phase-to-ground, phase-to-phase, phase-to-phase-to-ground and three-phase short circuit faults. Alongside this, you will be shown what short circuits are, the need for short circuit analysis and the benefits derived from it.

Next, to analyze system faults, certain methodologies are employed. With the help of an examination of ‘per phase’ and ‘per unit’ methodologies, you will discover how system faults are analyzed with the use of symmetrical components. Manufacturers rate the equipment they produce according to their own MVA rating, specifying impedance as a percentage rather than per unit. Since their rating is in isolation (ie not connected to a system) when the equipment is eventually connected to a system it is necessary to work in another base. The course teaches you how to change bases and will examine per-unit analysis in transformers and the three-phase normalization process. Any set of asymmetrical three-phase quantities can be re-written as the sum of three symmetrical components. You will learn how to use symmetrical component equations in balanced and unbalanced systems with regard to positive, negative and zero sequences. Other properties you will study in relation to this will include the A operator, B-phase sequence and C-phase sequence.

In order to examine the asymmetrical three-phase fault analysis tool, this course shows you assumptions commonly made in three-phase fault studies and analyzes how they are applied to the different electrical fault types to derive useful equations. In power system analysis, mathematical models are a set of equations or relationships which appropriately describe the interaction between different quantities of a system. In this course, they will be used to symbolize and simulate single-line network diagrams for generators, transformers and transmission lines which are our symmetrical components of interest. Do you ever wonder why electrical faults occur? Are you curious as to the makeup of short circuits? Then this course is for you, especially maintenance personnel, electrical engineers, technologists and technicians working in the electrical power protection industry. To make the most of this course you should have a good understanding of per-unit analysis, symmetrical components, and laws and theorems related to three-phase electrical systems.