PC BASED TRANSFORMER PROTECTION USING WAVELETS

Abstract

The proposed work aims to develop a Wavelet transform technique for the protection of all types of transformers against fault situation/mal-operation of relay in real time. This is an emerging technology in the numerical/digital protection area, where FFT and some other techniques are currently widely used in the industry. Hardware circuits were developed to simulate different fault conditions occurring in transformer. For real time studies, an oscilloscope by Tektronix (TDS 220) was used to get waveforms. These waveforms were taken onto PC via RS 232 to study their characteristics using MATLAB. Transformer used was specially designed with 2 kVA rating and were provided with tapping on both primary and secondary to simulate for internal faults. It has primary voltage of 230V and secondary being 115V being in 1:2 transformation ratio. In this work, real time simulations were made for internal (both turn-turn and turn-ground) and over excitation cases