A Novel Solution to Restricted Earth Fault Low Impedance Relay Maloperation
In this paper, various methods of providing restricted
earth fault protection are discussed. The proper operation of high and
low impedance Restricted Earth Fault (REF) protection for various
applications has been discussed. The maloperation of a relay due to
improper placement of CTs has been identified and a simple/unique
solution has been proposed in this work with a case study. Moreover,
it is found that the proper placement of CT in high impedance method
will provide the same result with reduced CT. This methodology has
been successfully implemented in Al Takreer refinery for a 2000
KVA transformer. The outcome of the paper may be included in
IEEEC37.91 standard to give the proper guidance for protection
engineers to sort out the issues related to mal functioning of REF
relays.
[1] V K Metha & Rohit Metha, Principles of power system, ISBN:81-219-
2496-0.
[2] Sunil S Rao, Switchgear and protection, Khanna publishers, fourth
reprint, 1996.
[3] T60 transformer protection system, UR series instruction annual, version
7.2x, Manual P/N:1601-0090-AA1 (GEK-119568)
[4] High impedance restricted earth fault protection, technical guidance
notes, SIEMENS.
[5] IEEE guide for protective relay applications to power transformers,
C37.91-2000
[1] V K Metha & Rohit Metha, Principles of power system, ISBN:81-219-
2496-0.
[2] Sunil S Rao, Switchgear and protection, Khanna publishers, fourth
reprint, 1996.
[3] T60 transformer protection system, UR series instruction annual, version
7.2x, Manual P/N:1601-0090-AA1 (GEK-119568)
[4] High impedance restricted earth fault protection, technical guidance
notes, SIEMENS.
[5] IEEE guide for protective relay applications to power transformers,
C37.91-2000
@article{"International Journal of Electrical, Electronic and Communication Sciences:71154", author = "K. N. Dinesh Babu and R. Ramaprabha and V. Rajini and V. Nagarajan", title = "A Novel Solution to Restricted Earth Fault Low Impedance Relay Maloperation", abstract = "In this paper, various methods of providing restricted
earth fault protection are discussed. The proper operation of high and
low impedance Restricted Earth Fault (REF) protection for various
applications has been discussed. The maloperation of a relay due to
improper placement of CTs has been identified and a simple/unique
solution has been proposed in this work with a case study. Moreover,
it is found that the proper placement of CT in high impedance method
will provide the same result with reduced CT. This methodology has
been successfully implemented in Al Takreer refinery for a 2000
KVA transformer. The outcome of the paper may be included in
IEEEC37.91 standard to give the proper guidance for protection
engineers to sort out the issues related to mal functioning of REF
relays.", keywords = "Relay maloperation, transformer, low impedance
REF, MatLab, 64R, IEEE C37.91.", volume = "9", number = "8", pages = "969-6", }