Algorithm for a digital transformer differential protection based on a least-squares curve-fitting

Author

Degens, A.J.

Author_Institution

Delft University of Technology, Department of Electrical Engineering, Delft, Netherlands

Volume

128

Issue

3

fYear

1981

fDate

5/1/1981 12:00:00 AM

Firstpage

155

Lastpage

161

Abstract

An inrush-current detection algorithm is described. The algorithm is based on a least-squares curve fitting of the sampled differential current by a decaying DC and five harmonic components. Inrush is detected on the ratio of the second harmonic and the fundamental component of the differential current. The sampling frequency and data window are chosen in close relation to noise amplification and frequency characteristics of the digital filters developed. In spite of the rather detailed curve fitting the calculation burden is kept to a minimum by a suitable choice of the time reference. The algorithm is tested offline with simulated fault data

Keywords

digital filters; least squares approximations; overcurrent protection; relay protection; transformer protection; differential protection; digital filters; frequency characteristics; harmonic components; inrush-current detection algorithm; least squares curve fitting; noise amplification; sampled differential current; simulated fault data; transformer protection;

fLanguage

English

Journal_Title

Generation, Transmission and Distribution, IEE Proceedings C

Publisher

iet

ISSN

0143-7046

Type

jour

DOI

10.1049/ip-c.1981.0026

Filename

4643362