Analysis of 3-Phase Symmetrical and Unsymmetrical Fault on Transmission Line using Fortescue Theorem

Abstract

This paper investigates the major faults affecting the transmission of electrical energy after power has been generated from the power generating station. In a 3-phase transmission line, faults arise due to numerous causes such as aircraft, line breaks due to the excessive loading, heavy winds, trees falling across the lines etc. The faults faced in a 3-phase transmission line are broadly categorized into two main parts, namely: unsymmetrical faults and symmetrical faults. Furthermore, there is another classification of faults in 3-phase transmission lines such as: shunt type of faults and series type of faults, but this paper discusses the shunt type of faults which create short circuit on single line to ground (L-G) faults between two conductors or line to line (L-L) faults, or double line to ground (LL-G) or (triple) three line to ground (LLL-G) faults. This was achieved using the Fortescue Theorem on MATLAB software. The results show that the single L-G faults occur more frequently followed by the L-L faults, LL-G faults, and LLL-G faults. This study is essential to evaluate the power reliability and stability of power transmission lines.