Design and Performance Evaluation of a High-Impedance REF Scheme for MV/LV Transformers

Author

Apostolopoulos, Christos ; Tsakiris, Dimitris

Author_Institution

PROTASIS SA, Athens, Greece

Volume

51

Issue

6

fYear

2015

Firstpage

5398

Lastpage

5409

Abstract

This paper presents the detailed engineering study conducted to design a high-impedance restricted earth fault (REF) scheme for four 11/0.415-kV, Dyn11, and 2500-kVA power transformers in an industrial power system. Analytical calculations carried out to specify the components constituting the REF scheme and to determine the appropriate relay settings are provided. The proposed REF scheme is evaluated using reliable Alternative Transients Program-Electromagnetic Transients Program simulations. The obtained results validate the adequacy of the design and highlight the advantages of using such a protection, such as fast and reliable operation even under severe current transformer saturation conditions.

Keywords

EMTP; electrical faults; power transformers; alternative transients program simulations; apparent power 2500 kVA; electromagnetic transients program simulations; high-impedance REF performance; industrial power system; low voltage transformer; medium voltage transformer; power transformers; restricted earth fault; voltage 0.415 kV; voltage 11 kV; Circuit faults; Current transformers; Earth; Impedance; Power transformers; Relays; Resistors; ATP-EMTP; Alternative Transients Program???Electromagnetic Transients Program (ATP???EMTP); CT saturation; Restricted earth fault protection; current transformer (CT) saturation; high impedance; high-impedance; protective relaying; restricted earth fault (REF) protection;

fLanguage

English

Journal_Title

Industry Applications, IEEE Transactions on

Publisher

ieee

ISSN

0093-9994

Type

jour

DOI

10.1109/TIA.2015.2435003

Filename

7110353