DETECTION OF LOW-CURRENT SHORT CIRCUITS

Devices presently in use by the rail transit industry can adequately detect and respond to overload fault currents. Detection of less than overload fault currents is particularly difficult because the characteristics of such currents resemble characteristics normally associated with train or power switching operations. Consequently, trains may continue to operate until the fault current becomes large enough to be detected by overload devices or until the fault results in smoke and fire activity. The latter is particularly hazardous in tunnel systems. The objective of this research was to identify and provide preliminary evaluation of detection methods and equipment to enhance transit system safety through reliable detection of electrical faults that are not detected by circuit breaker overload protection. The Charles T. Main, Inc., researchers conducted an extensive survey of rail transit systems, electrical industry organizations, and electrical equipment supopliers worldwide to determine how the problem is currently being handled and to identify methods and equipment that may provide potential solutions. Information collected on the consequences of low-current faults did not identify evidence of highly dangerous incidents. Reports indicated damage to facilities and eqiupment and incidents of localized smoke and fire. It appears that several types of low-current fault detection devices are in use in countries other than the United States that could be adapted for use by transit systems in this country. Field testing, in cooperation with an electric rail transit system, is recommended as the next appropriate step toward improved low-current fault detection.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/nctrp/rpt7/7.pdf
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/07324839
• Supplemental Notes:
  • Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Sagar, N S
• Publication Date: 1984-12

Media Info

• Media Type: Digital/other
• Features: Appendices; Figures; References; Tables;
• Pagination: 216 p.
• Serial:
  • NCTRP Report
  • Issue Number: 7
  • Publisher: Transportation Research Board
  • ISSN: 0732-4839

Subject/Index Terms

• TRT Terms: Circuit breakers; Instrumentation; Protection; Rail transit facilities; Railroad electrification; Rapid transit cars; Safety; Safety equipment; Short circuits
• Old TRIS Terms: Fault currents; Protective devices
• Subject Areas: Administration and Management; Highways; Maintenance and Preservation; Public Transportation; Railroads; Safety and Human Factors; Security and Emergencies; Terminals and Facilities; Vehicles and Equipment; I61: Equipment and Maintenance Methods;

Filing Info

• Accession Number: 00451143
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Nov 30 1985 12:00AM