| Title |
A Comparative Analysis of Fuzzy Logic-Based Relaying and Wavelet-Based Relaying for Large Transformer Protection |
| Authors |
박철원(Park, Chul-Won) ; 박재세(Park, Jae-Sae) ; 신명철(Shin, Myong-Chul) |
| Keywords |
EMTP ; fuzzy logic ; large transformer protection ; magnetizing inrush ; percentage differential relaying ; wavelet transform |
| Abstract |
Percentage differential characteristic scheme has been recognized as the principal basis for large transformer protection. Nowadays, relaying signals can contain second harmonic component to a large extent even in a normal state, and second harmonic ratio indicates a tendency of relative reduction because of the advancement of transformer's core material. And then, conventional second harmonic restraint differential relaying exposes some doubt in reliability. It is, therefore, necessary to develop a new algorithm for the effective and accurate discrimination. This paper deals with advanced fuzzy logic based relaying by using flux differential, and a new fault detection criterion logic scheme by using wavelet transform. To comparative analysis of proposed techniques, the paper constructs power system model including power transformer, utilizing the EMTP, and collects data through simulation of various internal faults and magnetizing inrush. The proposed fuzzy relaying and a new fault detection scheme were tested. The former, fuzzy relaying, was proven to be faster and more reliable than the latter. |