Stray Current Control of Direct Current-Powered Rail Transit Systems: A Guidebook

2020 ◽  
Author(s):  
◽  
◽  
◽  
◽  
Keyword(s):  
Direct Current ◽  
Current Control ◽  
Rail Transit ◽  
Stray Current ◽  
Transit Systems

Understanding Stray Current Mitigation, Testing and Maintenance on DC Powered Rail Transit Systems

2013 ◽  
Author(s):  
Saud Memon
Keyword(s):  
Current Control ◽  
Design Criteria ◽  
Light Rail ◽  
Rail Transit ◽  
Stray Current ◽  
Soil Resistivity ◽  
Transit System ◽  
Transit Systems ◽  
Testing Procedures ◽  
Transit Agencies

All direct current traction power systems using rails for return of traction current have a level of current leakage. This leakage of current is dependent on both design and operating factors affecting the efficiency of the rail return path and is referred to as stray current. Stray currents have been detected since the first electric railways were placed into operation during the latter half of the nineteenth century and have serious effects on utility structures and the neighboring infrastructure at large. Stray currents can create safety hazards thereby rendering the design of stray current mitigation an important element of the overall design of a rail transit system. Like any other design/construction project, a baseline survey is an important and significant step in the data collection and fact finding process for a light rail system. Such a survey would aid in finding the soil resistivity data and the results of the stray current levels on existing buried metal utilities. Similarly defining the design criteria for stray current mitigation, monitoring, and testing for a new light rail design project is also important. Most of the design criteria for the older rail transit systems have been developed as an aftermath of the corrosion problem and/or after the design of new extension to the system. Some older transit systems still do not have a specified design or mitigation criteria for stray current, and corrosion issues are handled as they surface and are prioritized based on severity. In the absence of guidelines, it is hard to understand the reasoning behind the limiting criteria suggested in the transit agency manuals particularly when there is no record of testing or soil resistivity investigation. For these older transit systems the limiting criterion was developed based on the information from other transit services. Having applicable design criteria for stray current control and mitigation will help standardize the process for the transit and will lower the cost of mitigation. This paper has been written by a Civil Engineer with an effort to understand the source and the scientific reasoning behind the limiting values suggested by the transit agencies associated with stray current testing procedures and its control. In order to understand the limited stray current corrosion criteria and the respective testing, various transit agencies were interviewed. These interviews were supplemented by a thorough review of the respective transit agency criteria manual/guidelines (where such information was available and accessible). Critical evaluations of the testing procedures were conducted to analyze if these tests and mitigation methods were effective.

Stray Current Simulation Models for Direct Current Transit System: An Industry Perspective

2015 ◽  
Author(s):  
Saud Memon ◽  
Paul Fromme
Keyword(s):  
Direct Current ◽  
Simulation Models ◽  
Stray Current ◽  
Transit System ◽  
Transit Systems ◽  
Current Leakage ◽  
The Impact ◽  
Modeling Principles

This paper presents and evaluates the different modeling principles developed, and in use, to control stray current leakage for Direct Current (dc) powered transit systems. The aim is to understand the stray current simulation models, explain their limitations, and to understand the impact on stray current leakage due to different grounding schemes adopted by the dc powered transit operators.

Assessment of grounding, bonding, and insulation on rail potential and stray currents in a direct current transit system

2009 ◽  
Vol 223 (3) ◽  
pp. 229-240 ◽  
Author(s):  
Y-S Tzeng ◽  
C-H Lee
Keyword(s):  
Direct Current ◽  
Current Collector ◽  
Rapid Transit ◽  
Stray Current ◽  
Transit System ◽  
Transit Systems ◽  
Simulation Results ◽  
Blue Line

This article presents the effects of different grounding strategies (ungrounded, direct grounded, and diode grounded), bonding, and insulation on rail potential and stray currents in the Taipei rapid transit systems (TRTSs). The TRTS is a direct current transit railway and its running rails are used as the return conductor for traction currents. The advantage is that no dedicated return conductor is required, whereas the disadvantages are rail potential and stray-current problems. Thus, the analysis of grounding strategies is important and necessary. Moreover, the effects of cross-bonding of the running rails and stray-current collector cables (traction earth conductors) are investigated since bonding is usually used to balance traction negative return currents, to reduce resistances of the negative return circuit, as well as to decrease rail potential. Meanwhile, the effects of insulation on stray currents are also described. Simulation results for the Blue line are presented in TRTS.

Stray Current Control in DC Mass Transit Systems

2005 ◽  
Vol 54 (2) ◽  
pp. 722-730 ◽  
Author(s):  
I. Cotton ◽  
C. Charalambous ◽  
P. Aylott ◽  
P. Ernst
Keyword(s):  
Mass Transit ◽  
Current Control ◽  
Stray Current ◽  
Transit Systems
Sign in / Sign up

Export Citation Format

Share Document