A New Approach to Current Transformer Saturation Compensation for Transmission Line Differential Protection

Abstract

A non-linear autoregressive network with external inputs (NARX) model to reconstruct the current transformer (CT) secondary waveform distortion in the presence of protected transmission lines is presented. The qualitative analysis carried out on the autonomous model reveals the accurate performance of the current differential relay, because of the ability of the NARX to make accurate predictions and signal reconstruction even when faced with noisy or incomplete datasets. The suggested method uses samples of the line-protected remote current signal to produce a desired waveform. The unsaturated section is artificially expanded because it can estimate up to one sample after saturation with a respectable level of accuracy. The proposed method is evaluated by MATLAB and PSCAD software. The effectiveness of the suggested method for different fault types under varied situations has been proved. The simulation outcome confirms the method’s high accuracy concerning the unusual system conditions in the presence of CT saturation.

Keywords:

• current differential relaying
• transmission networks
• wide area protection
• signal reconstruction
• current transformer saturation
• NARX

DISCLOSURE STATEMENT

The authors declare that they have no conflict of interest.

Additional information

Funding

None.

Notes on contributors

Valiolah Ebrahimian

Valiolah Ebrahimian was born in Khorramabad, Iran, in 1972. He received his B.Sc. in 2002 at the Water and Electricity University, Iran, and his M.Sc. in 2017 at the Azad University, Iran, all in Electrical Power Engineering. His areas of interest include power system protection, power system operation and control, and substation automation systems.

Farhad Namdari

Farhad Namdari was born in Khorramabad, Iran, in 1972. He received his B.Sc. in 1995 at the Iran University of Science and Technology (IUST), M.Sc. in 1998 at the Tarbiat Modarres University (TMU), Iran, and Ph.D. in 2006 at the IUST all in Electrical Power Engineering. He is a Professor in the Department of Electrical Engineering at Lorestan University, Khorramabad, Iran. He has published more than 140 technical journals and Conference Papers in English/Persian. His areas of interest include power system protection, smart grids, power system operation and control, and artificial intelligence (AI) techniques in power systems.

Mahmoud-Reza Shakarami

Mahmoud-Reza Shakarami was born in Khorramabad, Iran in 1972. He received his M.Sc. and Ph.D. degrees in Electrical Engineering from the Iran University of Science and Technology, Tehran, Iran, in 2000 and 2010, respectively. He is currently a Professor in the Electrical Engineering Department of Lorestan University, Khorramabad, Iran. His current research interests include power system dynamics and stability, FACTS devices, and distribution systems.