A stand-along digital protective relay for power transformers

Author

Hermanto, Ivi ; Murty, Y.V.V.S. ; Rahman, M.A.

Author_Institution

Fac. of Eng. & Appl. Sci., Memorial Univ. of Newfoundland, St. John´´s, Nfld., Canada

Volume

6

Issue

1

fYear

1991

fDate

1/1/1991 12:00:00 AM

Firstpage

85

Lastpage

95

Abstract

The complete design of a stand-alone prototype digital protective relay for three-phase power transformers is described. The major emphasis is on the detailed description of the hardware and software of the prototype relay. The protection functions implemented include: a percentage differential protection with a second-harmonic restraint for magnetizing inrush and a fifth-harmonic restraint for overexcitation conditions, and a separate protection for high-impedance primary and secondary ground faults. The relay design is tested with the Fourier algorithm, and any other relay algorithm can be used by replacing only one subroutine. The relay hardware consists of a data acquisition board and a digital processing board which is based on the TMS320E15 processor. Sample real-time test cases are discussed. The results show that the relay never misoperated and correctly identified all the faults

Keywords

computerised control; power engineering computing; power transformers; relay protection; 3-phase power transformers; Fourier algorithm; TMS320E15 processor; data acquisition board; digital processing board; high-impedance ground faults; overexcitation conditions; percentage differential protection; real-time test cases; second-harmonic restraint; stand-along digital protective relay; Digital relays; Hardware; Magnetic separation; Power transformers; Protection; Protective relaying; Prototypes; Software prototyping; Surges; Testing;

fLanguage

English

Journal_Title

Power Delivery, IEEE Transactions on

Publisher

ieee

ISSN

0885-8977

Type

jour

DOI

10.1109/61.103725

Filename

103725