Skip links



Slatt Substation, Arlington

This project involved the expansion of the 500kV switchyard and construction of a new 230kV switchyard. This enabled the California-Oregon Intertie (COI) rating to be increased to 4800 MW and facilitated 846 MW of generation from Shepherds Flat Wind Farm to be interconnected with the BPA system. Elcon was responsible for the following:

  1. Slatt 500kV portion:
  • Design a new 500kV relay house including 46 new racks, 3 TF, cable tray system, AC/DC panels, lighting, station battery, and battery chargers.
  • Design the addition of three new 500kV breaker and a half bays: bay 10, bay 16, bay 21 and capacitor bank bay 15.
  • Design to install 500MVAR shunt capacitor, using a redundant set of SEL-287V for voltage differential, two sets of Basler BE1-951 for overcurrent protection, and SEL-2411 as programmable logic controller.
  • Design the relocation of the Coyote Springs line from the West bus into Bay 21, and move Buckley line into bay 16. Replace existing Coyote Springs line relays with SEL-421, ABB RED-670, and two sets of PTR-1500 for MW transfer trip.
  • Design to install new East and West bus differential relaying using two sets of ABB RED-521.
  • Design to install a new Digital Fault Recorder (DFR) system with BEN 6000.
  • Design to replace the controls for the entire 500kV switchyard and using Shark 200 for all Amp/Watt/Var
  • Replaced the existing SER and SCADA alarm system with the new GE D20 for the 500kV substation.
  1. Slatt 230kV portion:
  • Design a 230kV control & relay house including 27 new racks, 2 TF, cable tray system, AC/DC panels, lighting, station battery, and battery chargers.
  • Design to add six 230kV breakers as a breaker and a half station, with five bays, and two capacitor groups. The relaying is configured as a ring bus with a plan of adding three more future bays and one future cap group.
  • Design control and protection for the Shepherds Flat #1 and #2 lines with the redundant sets of SEL-311L, BE1-951 BFR.
  • Design the controls and protection for the new 500kV/230kV transformer bank, using the redundant sets of ABB RET-670 transformer differential.
  • Design to provide protection to two capacitor groups using two sets of SEL-287V Voltage Diff, and two sets of Basler BE1-951 for three phase & neutral overcurrent relay.
  • Design to provide protection for the West bus using redundant set of ABB RED-521 differential relays.
  • Design SER/SCADA alarm system using GE D20.

Owner: Bonneville Power Administration

Location: Arlington, OR

Project Features:

  • 500kV and 230 kV control and relay house