DENISON DAM TRANSFORMER, BUS, SWITCHGEAR
Denison Power Plant
351 Corps Road
Denison, TX 75020

Initial Mobilization / Completion Date

9/28/2020 - 3/18/2022

Contract Amount:

$3,997,799.00

Owner:

US Army Corp of Engineers
Tulsa District POC: Brian Hutchison (CO)

Job Number:

19-2073

General Contractor

Koontz Electric Co., Inc.
PM: James Zimmerman

The work performed under this contract consisted of providing the labor, equipment, and materials to remove the existing single phase GSU transformers, the 15 kV switchgear for units 1 and 2, the iso-phase bus between the generator and the transformers, connections to the new three phase gas insulated transformers, new segregated phase bus, new non-segregated phase bus, new 15 kV switchgear, new controls and relaying, new control room switchboard panels, new motor control centers, and all the necessary auxiliary and ancillary equipment and systems required necessary to install the equipment at the Denison Powerhouse to make it fully operational. The new GSU power transformers were furnished by Koontz Electric on a separate contract.

  • The work included electrical work and related work including, but not limited to, the following:
  • Removed and disposed of seven (7) single phase GSU transformers (2 three phase transformer banks and 1 spare) including oil, piping, cabling and conduit, equipment no longer to be used and the disconnection from the overhead transmission line.
  • Removed and disposed of the two 15 kV switchgear lineups (unit 1 and unit 2) including the cable and conduit no longer to be used.
  • Removed and disposed of the existing iso-phase bus for units 1 and 2 to include the sections from the generator to the switchgear and from the switchgear to the six GSU transformers.
  • Removed insulating oil from the existing “clean” and “dirty” insulating oil storage tanks and clean the tanks.
  • Removed the existing oil filled transformer nitrogen piping, fire suppression deluge piping, oil piping systems, and their support structures.
  • Designed, manufactured, tested, and delivered two new switchgear assemblies with all breakers and auxiliary equipment.
  • Designed, manufactured, tested, and delivered new segregated bus for connection between the generator main leads and the new 15 kV switchgear and non-segregated bus for connection of the new switchgear to the new GSU transformers.
  • Connected the power and control cables and conduits to the new Gas Insulated Transformers T1 and T2 on Denison Powerhouse tailrace deck Connected the cable from the new high voltage transformer bushings to the overhead transmission lines.
  • Modified the existing transformer pedestal. Designed and installed new transformer foundation to allow the transformer supplier to place the transformers in the final location. After the transformer was placed in its final location, welded, and provided touchup paint.
  • Removed existing surge arresters and brackets and provided and installed new mounting brackets and new surge arresters on the high voltage side of the new transformers.
  • Installed, leveled, and tested new 15 kV switchgear for units I (SJ1) and 2 (SJ2) including all cable and conduit connections to make the equipment fully operational both locally and remotely as well as connection of the 15 kV cable connections to the existing excitation system transformers and the existing station service transformer.
  • Installed, adjusted, leveled, and tested new segregated phase bus from the new 15 kV switchgear to the existing generator main leads including the modification of the generator main leads to connect the new bus at the generator main floor to make it fully operational.
  • Installed, adjusted, leveled, and tested new non-segregated phase bus from the new 15 kV switchgear to the new GSU transformers (provided by others) and connect to the low voltage bushings to make it fully operational.
  • Furnished, installed, and tested the new 480 VAC-120/208 VAC Power center.
  • Furnished, installed, and tested two new motor control centers to supply power to powerhouse auxiliary systems to include programming internally mounted PLC.
  • Furnished and installed new grounding conductors to new equipment.
  • Layout, manufacture, wire, test and deliver two new control room main board rear panels for replacement of the existing transformer relay panels with new digital transformer relays.
  • Asbestos and lead remediation