Generator Breaker Disconnect Switches

Request for Information (RFI) #W912EF22RSN01 Hydropower Dam (plant) (located at NW part of the USA) The Army Corps of Engineers (Corps) is seeking information regarding the replacement of the generator breaker disconnect switches at one of its Hydropower Dams in the NW regions of the country. The overall project will involve the design, fabrication, and delivery of disconnect switches, buswork, and appurtenances. Removal of the existing and installation of the new disconnect switches, buswork, and appurtenances may be done by others. Services of an erecting engineer would be required to direct and supervise the installation. The plant has both General Electric Type ARA (Configuration 1) and Westinghouse Type CA (Configuration 2) air-blast breaker cubicle switchgear. The switchgear enclosures are mainly comprised of two parts, front and rear part, separated by solid physical barriers but are firmly attached to each other. The air blast breakers were replaced in the mid-2000's with the ABB SF6 breakers but the disconnect switches were retained at that time. The front breaker compartment houses the ABB SF6 generator circuit breakers, CTs and controls, and the rear compartment houses the disconnect switches, bus transition and surge capacitors. Each of the generator breakers has two sets of disconnect switches immediately upstream and downstream of the main unit breaker. The existing disconnect switches are rated 15kV, 4000A are housed in the rear of the 15.5kV switchgear enclosure. The disconnects switches are connected to the 5000A rated breaker compartment via through-bushings that are part of the disconnect switch assembly. These disconnect switches are integral to the GE Type ARA and Westinghouse Type CA switchgear cubicles. Planned generator uprates at the plant require the existing disconnect switches and bus to be replaced with 5000A rated equipment. The two configurations for the rear compartment both have two sets of disconnect switches with a common manual operator, but the vertical location of the switches are different and the method of interconnection with the bus/breaker in the breaker compartment is different. Details of tasks are below: Technical Requirements for each configuration: 1. Enclosure Assembly The assembly should be rated for a minimum of 15.5kV, 5000A, and 63kA with 110kV BIL to match the rating of the front breaker compartment. Enclosure assembly should maintain the bus transition compartment above the location of the actual disconnect switches Must have a solid barrier between the breaker compartment and switch compartment so that there is complete electrical and physical isolation between the breaker compartment and switch compartment. Must have solid barriers between the different phases of the bus and disconnect switch and between the opposite switch in order to keep the phases segregated. Transition to isophase bus on the top via seal-off bushings (bus to the transformer). Transition to isophase bus on the bottom (bus to generator). 2. Bus Transition Compartment Transition the bus spacing of the incoming the isophase bus to the spacing required in the disconnect switch compartments All bus work inside the enclosure shall be copper and rated for 5000A continuous and braced for a minimum of 63kA short time withstand (2 sec). All contact surfaces will be silver-plated. Existing solid inter-phase barriers are to be retained to ensure phases are completely segregated within the compartment. Must include a 15kV, 0.25 microfarad surge capacitor for each phase in the bus transition area above the disconnect switches on the transformer bus side. This is required to achieve the installed breaker interrupting rating. 3. Disconnect switches Disconnect switch shall meet the applicable requirements of IEEE C37.20.4 for Indoor AC Switches (1 kV to 38 kV) for Use in Metal-Enclosed Switchgear Rated 15kV, 5000A continuous, 63kA short time withstand capability (2 sec) All contact surfaces will be silver plated. All 3-poles of each switch shall be operated simultaneously. Preference is to have both switches operated with a single manual operating handle - similar to the current configuration - but operation from independent handles is acceptable as long as the interlocking scheme can be maintained 4. Interconnection with Existing Breaker Cubicle Existing interconnection is via through bushings and terminal adapters to either solid bus (Configuration 1) or braided flexible links (Configuration 2). The interface does not need to match the existing arrangement however the transition used must be capable of carrying 5000A continuous, be braced to have a fault withstand capability of 63kA, and not exceed the temperature rise requirements of the breaker cubicle per IEEE C37.20.3. Solid copper busbar and insulating busbar supports may be used as long as a solid barrier between the breaker compartment and the disconnect switch compartment is maintained. Must maintain the existing access for the installation and removal of current transformers on both the incoming bus and outgoing bus from the breaker cubicle side with protective housing/covers. 5. Miscellaneous IR viewing windows must be provided for each switch to provide visual verification of switch position and conducting IR scans Kirk-Key interlocks will be required to be installed to interlock the operation of the switch with the breaker position and the doors to the MV compartment of the breaker cubicle. Retain the existing current trasnformers Viewing light with light switch should be retained or new arrangement provided. The compartment doors and covers should be provided with screened louvers for ventilation Please see appendix for drawings and pictures of generator breaker switchgear and disconnect switches. The government is interested in: (1) Vendor's expertise in determining if the work is feasible or has been done in the past (2) Vendor's experience with retrofitting similar switchgear compartments with new disconnect switches, buswork, and appurtenances to meet the required ratings outlined in the technical requirements. (3) Vendor's experience with performing the field installation (4) Vendor's experience in providing erecting engineer services to direct and supervise the installation by others. (5) Estimated lead time to design and fabricate the required parts. (6) Estimated timeframe required to retrofit one cubical assembly. Provide description of the vendor's capabilities to perform such work, list of current or previous projects of similar work, and sample drawings for similar work. Please provide the minimal time period necessary to complete the above tasks: Comments: ____________________________________________________________. Please provide comments regarding the feasibility, or any other issues, for the anticipated time schedule described below: Government Recommendation: A work window beginning in early March of 2022. Comments: _________________________________________________________________. Contractor's Recommendation: Anticipated time schedule, if different from the Government's. Comments: _________________________________________________________________. Please provide the following: 1. A list of current or past projects demonstrating technical experience with work of a similar nature to that listed in the Summary Scope of Work. For each project submitted, provide a brief narrative statement of the work involved, your firm's role in the project, the dollar value and the completion date. Include a statement detailing any special qualifications and certifications, applicable to the scope of this project, held by your firm and/or in-house personnel. 2. A reference list for each of the projects submitted in #1 above. Include the name, title, current phone number and email address. 3. Provide a statement of your firm's business size (HUBZone, Service Disabled Veteran Owned, 8(a), small disadvantaged, or woman-owned) with regards to the NAICS code listed above. 4. Cage Code and DUNS number. Please submit your response to the questions and any comments no later than 19 November 2021 to Ms. Hillary Morgan at hillary.a.morgan@usace.army.mil NOTE: THIS IS A REQUEST FOR INFORMATION (RFI) SOURCES SOUGHT (SS) NOTICE ONLY. This RFI/SS is issued solely for information and planning purposes and does not constitute a solicitation or obligation on the part of the government. No reimbursement will be made for any costs associated with providing information in response to this RFI. Any information submitted in response to this announcement is strictly voluntary. The Corps of Engineers reserves the right to utilize any or all of the RFI response(s) in its planning efforts.