Upcoming Bid VF4069JLH Boggs Substation Switchgear (Buy America Preference)

This document is the issued-for-bids engineering drawing package for a 69/12.47kV distribution substation located in Phoenix, Arizona, covering Substation Bays 1 and 2. The design is prepared for Salt River Project (SRP), as indicated by SRP customer and material references. The package includes one-line and three-line diagrams for both the 69kV terminal and the 12.47kV switchgear, transformer connection diagrams, bay and transformer protection/control schematic diagrams, switchgear breaker schematics, auxiliary power AC/DC schematics, and switchgear unit connection, layout, and nameplate drawings.

The substation is fed at 69kV and steps down to a 12.47kV (7.2kV line-to-ground) distribution voltage through two 30/40/50 MVA transformers (56 MVA at 55 degrees C), ONAN/ONAF/ONAF cooled, delta-grounded wye, with a 67kV to 12.47Y/7.2kV ratio. Each transformer is protected by redundant SEL-787 transformer differential relays (87Ta/87Tb) with sudden pressure relay trip inputs, protective relay cut-out switches, and low gas alarm/lockout monitoring. Low-side protection uses SEL-487B bay protection relays providing bus differential (87), instantaneous and time overcurrent (50/51), underfrequency (81), and breaker failure (50BF) functions, with virtual low-output tripping schemes.

The 12.47kV switchgear consists of metal-clad units with a 3000A main bus rated 15kV, 40kAIC, one main breaker (111) and two feeder breakers (112, 113) per bay, fed through 3000-5A bushing CTs and 7200-120V bus potential transformers. Kirk key interlocks coordinate the 69kV transformer protector with 12kV breaker operation. DC control power is 48V, and auxiliary AC is 120/240V for switchgear lighting, receptacles, and 230V/150W heaters. Protection and control communications are delivered via Ethernet DNP3 channels and IEC 61850 messaging, with trip-on-communications-failure logic via output 403.

The drawing package is marked "Issued for Bids" with design revisions dated from May 2019 through December 2020. Key references include the 12.47kV one-line (SK-AMP-8.2), three-line diagrams (SK-AMP-9.6 and SK-AMP-9.7), transformer and bay protection schematics (SK-AMP-10.112-1/-2), switchgear breaker schematics (SK-AMP-10.113), auxiliary power schematics (SK-AMP-10.114), and switchgear connection and layout drawings (SK-AMP-11.112 and SK-AMP-12.110). No bid submission deadline, evaluation criteria, or contract contact information is stated within this document; interested contractors should contact SRP directly for the complete solicitation package.