Numerical overcurrent power relay enhancement based on integrated discrete wavelet transform

Abstract

Abstract As electrical power demands increase, 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 diverse types and functions play a significant role in electrical power system operation and protection as well. 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 current waveform samples are collected and processed to continuously monitor and detect faults. This large number of samples needs a bigger storage data real state and longer time to compile. Therefore, optimization is needed to improve current relay reliability and accuracy with much fewer samples. As a result, in this work, the wavelet transform algorithm with its wide spectrum feature of waveform analysis and decomposition process will be evaluated as an enhancement tool in current relay performance. Using MATLAB/Simulink, a simulation of modern digital current relay and the unique characteristics of wavelet transform (de-noising, mining, and decomposition) will be executed to evaluate the ability of advance fault detection based on a smaller number of current waveform data with respect to conventional analysis algorithm. As a result, by comparing the performance of the new proposed setting with the conventional digital overcurrent relay compiling algorithm, a promising result in terms of less than half the data samples were collected for faster compiling process and shorter relay response time was achieved.