A two-relay differential protective scheme for Le-Blanc transformers

A Le-Blanc transformer is a special winding connection transformer for the single-phase power supply of an electrified railway and it has been installed in the electrified railway of Taiwan (Tairail) for more than twenty years. It is well-known that the main electrical protection of large capacity t...

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Bibliographic Details
Published inIEEE transactions on power delivery Vol. 14; no. 3; pp. 857 - 862
Main Authors LU, K.-C, NANMING CHEN
Format Journal Article
LanguageEnglish
Published New York, NY IEEE 01.07.1999
Institute of Electrical and Electronics Engineers
Subjects
Applied sciences
Current transformers
Design engineering
Electrical engineering. Electrical power engineering
Exact sciences and technology
Joints
Line current
Phase transformers
Power electronics, power supplies
Power supplies
Power system protection
Power system relaying
Power transformers
Protective
Protective relaying
Rail transportation
Railroads
Railway electrification
Railway engineering
Railways
System testing
Transformers
Waveform
Current transformer
System performance
Simulation
Dependability
Phase diagram
Differential protection
System design
Laboratory test
Power supply
Power electronics
Electric vehicle
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Summary:A Le-Blanc transformer is a special winding connection transformer for the single-phase power supply of an electrified railway and it has been installed in the electrified railway of Taiwan (Tairail) for more than twenty years. It is well-known that the main electrical protection of large capacity transformers is differential protection. As the special winding connection and current relationship of Le-Blanc, differential relays are not easy to apply directly without using the special turn ratio current transformers. Therefore, the purpose of this paper is to design a differential protective scheme that is built by normal turn ratio current transformers connected for Le-Blanc transformers. According to the phasor combination method, a two-relay differential protective scheme that combines the primary line currents to match the secondary line current phases of Le-Blanc is proposed in this paper. For evaluating the performance of the proposed scheme, a practical design example using the parameters of a Tairail's Le-Blanc transformer and some scaled down data of the field test system in our laboratory are also presented in this paper.
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 23
ISSN:0885-8977
1937-4208
DOI:10.1109/61.772324