Analyzing Transit AC and DC Traction Power Networks

Numerous software programs have been developed to analyze AC power utility systems and DC transit traction power networks. Often, the two systems are studied separately, as the impact of DC loads on the utility medium voltage system is not significant in many cases. However, this is not always the case. Some US transit agencies have their own AC distribution system, using medium voltage to supply traction power substations and auxiliary loads. The AC distribution system is normally fed from several utility sources to mitigate the impact from a partial utility outage. This is the case with the Bay Area Rapid Transit District (BART) and Sound Transit’s tunnel (ST) systems. In the unique case of the Massachusetts Bay Transportation Authority (MBTA) system, the agency’s power to their 13.8 kV AC distribution system is distributed from a centralized location known as South Boston Power Complex (SBPC). Normally, the SBPC receives power from NSTAR’s 115 kV grid, but if necessary, backup power can be provided from MBTA’s own 68 MVA combustion turbine generator. In the aforementioned AC distribution systems, the DC substation loads usually present the heaviest power demand. Due to the nature of transit system operation, the substation power demand varies rapidly which directly influences the AC load flow. Consequently, the interactions between the two systems can only be determined by using a comprehensive AC & DC study approach. This paper will present the methodology and tools being applied to MBTA’s distinct distribution system in order to perform comprehensive AC and DC load-flow, short-circuit, and protective relay device coordination studies.

• Record URL:
  http://www.apta.com/mc/rail/previous/2014/papers/Pages/default.aspx
• Supplemental Notes:
  • Abstract used with permission from American Public Transportation Association.
• Corporate Authors:

  American Public Transportation Association

  1666 K Street, NW, Suite 1100
  Washington, DC  United States  20006
• Authors:
  • Rauceo, Richard N
  • Kneschke, Tristan
  • Fitzgerald, Michael K
  • Martin, John A
• Conference:
  • 2014 Rail Conference
  • Location: Montreal Quebec, Canada
  • Date: 2014-6-15 to 2014-6-18
• Publication Date: 2014

Language

• English

Media Info

• Media Type: Web
• Features: Figures; References; Tables;
• Pagination: 11p
• Monograph Title: 2014 Rail Conference, American Public Transportation Association (APTA)

Subject/Index Terms

• TRT Terms: Alternating current; Demand; Direct current; Electric power generation; Electric power transmission; Electric substations; Turbines
• Identifier Terms: San Francisco Bay Area Rapid Transit District; Sound Transit
• Subject Areas: Energy; Operations and Traffic Management; Railroads; I10: Economics and Administration; I21: Planning of Transport Infrastructure;

Filing Info

• Accession Number: 01584104
• Record Type: Publication
• Files: TRIS
• Created Date: Dec 28 2015 3:00PM