Thesis (B.S.) -- Cagayan State University, 2023.
Includes bibliographical references.

Transmission lines are an important part of a power system. Transmission lines have high power transmission capacity, and they are prone to faults of larger magnitudes. Various faults occur in transmission lines. Therefore, protection relays are necessary to protect transmission lines. The purpose of protection system is to interrupt the faulty section from the healthy section because the fault currents may damage the electrical equipment. One of the protection relays is distance relay and it is mainly used in transmission line. Sometimes these relays are used for backup protection. Distance relays for determining the impedance need the voltage and current. Transmission lines are typically protected by distance protection relay. Distance relays are considered of highspeed class and can provide transmission lines. Nowadays, numerical distance relays have been used instead of using electromechanical and static distance relays. A microcontroller-based fault detection and location systems was used to accurately indicate and locate where fault had occurred. The proposed model was verified under different tests such as single line to ground (L-G) fault, double line to ground (L-L-G) fault, line to line (L-L) fault and three phase (L-L-L) fault. Sim Power System was used for modelling and simulation of distance relay, transmission lines and faults. The simulation results were obtained from MATLAB software shows the feasibility of analysis of transmission line protection with reactance type distance relay for single line to ground fault, double line to ground fault, line to line fault and three phase faults at different location of transmission lines. The difficulties understanding on operation of distance relay can be cleared by using MATLAB/SIMULINK software.

Keywords-Distance relay, Fault detection, Single line to ground fault (L-G), Double line to ground (L-L-G), Line to Line fault (L-L), Three phase fault (L-L-L), MATLAB/SIMULINK.