Fort Peck Powerhouse 1 Cubicle Room 15kV Switchgear Replacement Project

DESCRIPTION OF WORK:

The Fort Peck power plant has a series of 15kV class breakers that act as the generator breakers connecting the 3 generators in powerhouse 1 to the eastern and western power grids. Even through the breakers operate at 13.8kV their unique configuration requires switching orders from the transmission authority. Under the scope of this sources sought the 10 breaker cubicles and all associated buswork and equipment would be removed and replaced. This equipment will be replaced with 5 new breakers in the cubical rooms with associated equipment housed in additional cubicles. An additional 6 outdoor rated breakers will be installed in the switchyard. It is noted that the outage of the cubical room will be under tight time constraints given the support the power plant provides to the western power grid.

The complete 15 kV switchgear system will include:

• Metal-clad 15kV switchgear and breakers with instrumentation transformers (current and rack-out potential transformers). This includes 3 generator breakers and 2 tie breakers with associated bus work.


• 15kV outdoor circuit breakers with instrumentation transformers, 15kV disconnect switches and interconnecting 15kV aluminum bus system.


• Power, protection, control, and annunciation cabling between switchgear and control room.


• Control board modifications of the mimic bus, metering equipment and control switches.


• Revisions to existing protective relaying and synchronization scheme.


• 15kV Bus differential protection.


• New 15kV, 4000A cable bus to connect the 15kV switchgear in Cubicle Room to the new 15kV breakers in the switchyard.


• New feeders from the new 15kV breakers in the switchyard to transformers KX5A, KV7A, KZ2A, KY4A and the new reactors.


• The KV7A feeder is required to be installed in a 15kV air rated underground tray system.

The scope will also include the installation of two new 15kV, 12MVA reactors banks. These banks will be connected to outdoor 15kV switchgear. They will be providing MVAR support to the transmission systems off the tertiary of the 115kV/230kV KV7A Autotransformer.

Additionally, the scope incudes the replacement of the cable trays in the cable tunnel, the replacement in kind of the lighting distribution panelboards and dry-type transformers in the switchyard, the installation of warning lights at the three entrance points to the Cubicle Room, and an evaluation of the existing lighting system in the Cubicle Room.