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.
DC frame fault & ground fault field testing on TriMet Portland light rail system
2005-01-01
1690678 byte
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
RTD2005-70010 DC Frame Fault and Ground Fault Field Testing on TriMet Portland Light Rail System
British Library Conference Proceedings | 2005
|British Library Conference Proceedings | 2008
|Extraboard Performance: TriMet Case Study
Online Contents | 2012
|Analysis of Transit Signal Priority Using Archived TriMet Bus Dispatch System Data
British Library Conference Proceedings | 2005
|