Novel Algorithms for Distance Relay Protecting Transmission Line

Abstract

Power system conditions are dynamic in nature and integration of compensating devices makes system parameter changing continuously with time. In order to establish a reliable power network, protective devices are connected at every stages of a power system i.e. from generation to the load end. Traditional electromagnetic relay have limited performance for a dynamic power network where system conditions changes instantly. Digital relay have been introduced in protection schemes to overcome the limitation of electromagnetic relay. Digital relay perform according to the algorithm burn in their processor unit. In this thesis an attempt has been made for development of new algorithms of digital relays. newlineThe transmission system protection has been viewed entirely as a problem of signal processing. The task as a whole has been segregated into a smaller set of problems as brought out in form of three steps. 1) Fault detection, 2) Fault Classification and 3) Locating fault within the trip region. In this thesis the significant blocks such as fault detector, fault classifier and fault locator has been extensively studied and analyzed. New algorithms have been developed and feasibility of implementation has been discussed. newlinePhasor measurement units are essential part of modern power system. Phasor of alternating signals are widely used in protection and control schemes of power network. The sampled data of voltage and current signal are processed continuously through phasor estimation algorithms to obtain phasor values at each instant. Digital relays and controllers utilize these phasor values for system operation and control. Phasor estimation techniques based on discrete Fourier transform, discrete Wavelet transform and least square method are briefly presented and a comparative assessment has been carried out. The performances of phasor estimators have been evaluated on the basis of and#8215;Total vector error and and#8215;Transient monitor criterion. The effects of noises, harmonics and sampling frequency have been studied and discusse