A Lissajous Curve–Based Method for Busbar Protection

Abstract

In this paper, a novel time-domain method based on the orientation analysis of the superimposed current component Lissajous curves is presented for busbar protection. The conducted study has showed that the orientations of the superimposed current component Lissajous curves are different under internal and external fault conditions. These curves during internal faults are in the first and third quadrants, while under external fault conditions, they are oriented in the second and fourth quadrants. Using this property, an algorithm was designed to distinguish between internal and external faults. The proposed algorithm can identify internal faults up to a fault resistance of 500 Ω within a maximum of 2 ms with a sampling rate of 1 kHz. Moreover, the proposed scheme can detect evolving external to internal faults with CT saturation, internal faults during power transformer energization, and internal faults in the presence of white noise. Additionally, it is secure against external faults with current transformer (CT) saturation.