Until recently, TriMet traction power substations (TPSs) utilized a low resistance grounding system for the dc switchgear and rectifier equipment enclosures. The TPS negative bus was connected to a dc ground mat through a grounding diode. In addition to the basic dc overcurrent and rate-of-rise relays, each substation is provided with a low resistance frame fault current relay (device 64 C) and a negative-to-ground potential relay (device 64 V). Recently, TriMet has conducted several field tests: a) bolted frame fault tests, by applying 750 Vdc to the dc switchgear enclosure with the grounding diode connected and then with the grounding diode removed, b) ground fault tests, by connecting the OCS contact wire to an OCS pole ground rod (the ground fault tests were done with and without the diode), c) ground fault tests simulating an arcing ground fault, with a 9 ohm resistor inserted in series between the OCS contact wire and the OCS pole ground rod. This paper provides the test data and discusses the results of these frame fault and ground fault field tests. Technical analysis including personnel safety considerations are performed for various test configurations. The analysis will be focused on ground fault detection since most ground faults are undetected because of the very low ground fault current magnitudes, which are normally not detected by the rate-of-rise relay.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    DC frame fault & ground fault field testing on TriMet Portland light rail system


    Contributors:
    Pham, K.D. (author) / Heilig, T. (author) / Looijenga, K. (author) / Ramirez, X. (author)


    Publication date :

    2005-01-01


    Size :

    1690678 byte




    Type of media :

    Conference paper


    Type of material :

    Electronic Resource


    Language :

    English



    RTD2005-70010 DC Frame Fault and Ground Fault Field Testing on TriMet Portland Light Rail System

    Pham, K. D. / Heilig, T. / Looijenga, K. et al. | British Library Conference Proceedings | 2005


    JRC2008-63067 Track-to-Earth Potentials and Stray Current Monitoring on Portland TriMet MAX Light Rail System

    Pham, K.D. / Heilig, T. / Looijenga, K. et al. | British Library Conference Proceedings | 2008


    Extraboard Performance: TriMet Case Study

    Strathman, James G | Online Contents | 2012



    Rail Automatic Passenger Counter Validation and Sampling for National Transit Database and Internal Reporting at TriMet

    National Research Council (U.S.) | British Library Conference Proceedings | 2005