NUMERICAL VOLTAGE RELAY ENHANCEMENT BY INTEGRATED DISCRETE WAVELET TRANSFORM

Abstract

In today’s advanced technology and fast past energy demands, dependency on electrical power systems have reached the peak for daily human function in all life aspects. From high-voltage to low-voltage, big machines to a very articulated chipset, voltage optimization plays an important role in work operation and energy saving of electrical devices. Therefore, the importance of voltage relay in power systems is very significant to ensure normal operation, power system efficiency, power elements protection, and load safety. However, power system failures occur all the time due to numerous reasons which may lead to voltage variation (over-voltage or under-voltage). Such a variation can disrupt the essential elements of the power system and harm consumer load. Therefore, as network distribution cannot assure the same exact voltage at all day times, the need to optimize voltage relay has been a major issue in power system reliability and protection enhancements over the past few years. This paper aims to develop a unique technique to implement and test a new wavelet-based algorithm to modern numerical voltage relay to expedite voltage fault detection and precisely distinguish harmful voltage fluctuation levels. This enhancement will advance voltage waveform analysis to detect over-voltage/under-voltage phenomena, improve relay-tripping accuracy and relay response time. That is, wavelet transform has shown the ability to advance voltage relay operation with special properties of waveform de-noising, data extraction in an adjusted window, and data decomposition. Simulation of the Discrete Wavelet transform bank filters implemented into numerical voltage relay using MATLAB/Simulink has confirmed promising results as a quick voltage error detection based on few waveform data samples, faster data compiling process, and less complexity compared to typical conventional numerical voltage relay.