Commuter Rail AC Electrification Load-Flow Simulation Report - RTD

Commuter Rail AC Electrification Load-Flow Simulation Report Revision 1
arrangement will result in the feeder-to-rail and a catenary to rail systems that operate at a 25
kV nominal voltage with the feeder-to-catenary system that operates at 50 kV nominal voltage.
9.2.2 Electrical Power Utility Interface
The local power utility company Xcel Energy, is able to provide two 115 kV feeders to the two
traction power transformers at Sandown substation. At Argo substation, only one 115 kV feeder
is available. The traction power transformer primary winding phase connections should be
rotated among the available phases. Considering the loadings of the substation transformers,
when two transformers are located in Sandown and Argo substations, the following connections
are proposed to aid in balancing the load within the Xcel system:
• Sandown Substation, Transformer 1 – Phases A, B
• Sandown Substation, Transformer 2 – Phases B, C
• Argo Substation, Transformer 1 – Phases A, B
• Argo Substation, Transformer 2 – Phases C, A
The lowest loaded transformers, Sandown Transformer 1 and Argo Transformer 1, are
connected to the same phases (A & B), while the highest loaded transformers, Transformer 2
and Argo Transformer 2, are connected to different phases (B & C and C & A).
In the event that only one transformer is installed in Argo, the three transformers in Argo and
Sandown substations should be connected to the Xcel system as shown below:
• Sandown Substation, Transformer 1 – Phases A, B
• Sandown Substation, Transformer 2 – Phases B, C
• Argo Substation, Transformer 1 – Phases C, A
9.2.3 Power Supply System Design and Protection
The traction power transformers are liquid-immersed, constructed and tested in accordance with
IEEE 57 series of standards.
Each transformer typically includes its own complement of accessories and protective devices,
including phase and ground fault time overcurrent relays, as well as sudden pressure and
differential relays operating with no intentional delay. It is recommended that the system
protection is fully coordinated with the power utility.
02/27/2009 FRSC Page 29 of 250