Revision of IEEE Std C37.91-2000. This guide is intended to provide protection engineers and other readers with guidelines for protecting three-phase power transformers of more than 5 MVA rated capacity and operating at voltages exceeding 10 kV. In some cases, a user may apply the techniques described in this guide for protecting transformers of less than 5 MVA ratings or operating at voltages less than 10 kV. The guide provides information to assist protection engineers in applying properly relays and other devices to protect transformers used in transmission and distribution systems. General philosophy, practical applications, and economic considerations involved in power transformer protection are discussed. Emphasis is placed on practical applications. Types of faults in transformers are described. Technical problems with the protection systems, including the behavior of current transformers (CTs) during system faults, are discussed. Associated problems, such as fault clearing and re-energization, are discussed as well.
- Standard Committee
- PE/PSRCC - Power System Relaying and Control
- Status
- Superseded Standard
- PAR Approval
- 2007-12-05
- Superseded by
- C37.91-2021
- Superseding
- C37.91-2000
- Board Approval
- 2008-01-31
- History
-
- ANSI Approved:
- 2008-06-12
- Published:
- 2008-05-30
Working Group Details
- Society
- IEEE Power and Energy Society
- Standard Committee
- PE/PSRCC - Power System Relaying and Control
- Working Group
-
K16_C37.91 - Protecting Power Transformers Working Group
- IEEE Program Manager
- Malia Zaman
Contact Malia Zaman - Working Group Chair
- William English
Other Activities From This Working Group
Current projects that have been authorized by the IEEE SA Standards Board to develop a standard.
No Active Projects
Standards approved by the IEEE SA Standards Board that are within the 10-year lifecycle.
C37.91-2021
IEEE Guide for Protecting Power Transformers
Guidelines for protecting three-phase power transformers of more than 5 MVA rated capacity and operating at voltages exceeding 10 kV is provided to protection engineers and other readers in this guide. In some cases, a user may apply the techniques described in this guide for protecting transformers of less than 5 MVA ratings or operating at voltages less than 10 kV. Information to assist protection engineers in properly applying relays and other devices to protect transformers used in transmission and distribution systems is also provided. General philosophy, practical applications, and economic considerations involved in power transformer protection are discussed, with an emphasis on practical applications. Types of faults in transformers are described. Technical problems with the protection systems, including the behavior of current transformers during system faults, are discussed, as well as associated problems, such as fault clearing and post trip reenergization.
These standards have been replaced with a revised version of the standard, or by a compilation of the original active standard and all its existing amendments, corrigenda, and errata.
No Superseded Standards
These standards have been removed from active status through a ballot where the standard is made inactive as a consensus decision of a balloting group.
No Inactive-Withdrawn Standards
These standards are removed from active status through an administrative process for standards that have not undergone a revision process within 10 years.
No Inactive-Reserved Standards