Digital Protection of Transmission Lines

Abstract

High voltage transmission lines are designed to transfer large amount of power from one location to another. The length exposed to the environment is a major reason for occurrence of faults on the line. A fault on the lines affect the stability of the overall power system, which may lead to permanent damage of the equipment Relays are developed and installed to protect the line. Transmission line relays were electrometrical and solid state relays but now they are replaced by digital relays since evolution of microprocessors, because they have many advantages over the other relays. Digital relay use many algorithms to achieve detecting and isolating fault conditions, superimposed components technique is one of this algorithms and is used to protect sub transmission line, the performance and characteristics of superimposed components are studies and analysis in this thesis.