Citation

Pham K, Thomas R, Stinger W. Transp. Res. Circular 2003; (E-C058): 650-668.

Copyright

(Copyright © 2003, U.S. National Academy of Sciences Transportation Research Board)

DOI

unavailable

PMID

unavailable

Abstract

An overview is presented of an integrated approach to operational and safety issues when designing a DC traction electrification system (TES) for modern light rail and streetcar systems. First, the human body electrical circuit model is developed, and tolerable step and touch potentials derived from IEEE Standard 80 are defined. Touch voltages that are commonly present around the rails, at station platforms, and at traction power substations are identified and analyzed. Operational and safety topics discussed include: applicable codes and standards for electrical safety; traction power substation grounding; detection of ground faults; DC protective relaying schemes including rail-to-earth voltage sensing and nuisance tripping, and transfer tripping of adjacent substations; TES surge protection; electromagnetic and induced voltage problems that could cause disturbances in the signaling system; DC stray currents that can cause corrosion and damage to the negative return system, underground utilities, telecommunication cables, and other metallic structures; and emergency shutdown trip stations. To ensure safety of the project personnel and the public, extensive testing and proper and safe equipment operation are required. The testing includes factory testing of the DC protection system, first article inspection of critical TES components, inspection and field testing during commissioning. In addition, safety certification must be accomplished before the TES is energized and put into operation.