Numerical Overcurrent Power Relay Enhancement Based on Integrated Discrete Wavelet Transform

Abstract

  As electrical power demands increases, the need for advanced protection relays has surged as a vital element in the power distribution system.  That is, to ensure the continuity of power supply and eliminate abnormal faulty status, relays with different types and functions play a major role in electrical power system operation and protection as will.  In the power system, current variation faults may accrue for many reasons, which may harm power system components, load, and jeopardize human safety.  However, in now a day digital current relay, a large number of samples are collected and processed in order to continuously monitor and detect faults.  This large amount of samples needs a bigger storage data real state and longer time to compile, optimization is needed to improve current relay reliability and accuracy with much fewer samples.  Therefore, as this work aim toward optimizing the current relay, a substantial algorithm is needed for better current waveform analysis.  As a result, the Wavelet transform algorithm with its wide spectrum feature of waveform analysis and decomposition process will be used as an enhancement tool.  Using MATLAB/Simulink, a simulation, the unique characteristics of Wavelet transform (de-noising, mining, and decomposition) will be implemented into the modern numerical current relay to test the ability to advance fault detection based on less number of current waveform data. As this evaluation was compared with a typical conventional numerical overcurrent relay, a promising result in terms of less response time and compiling process was achieved.