Attachment_6_-_Questions___Answers_from_Site_Visit_0002.pdf

Trinity River Division GSU Transformer Replacements Central Valley Project, California Solicitation No. 140R2024R0002

Questions from Pre-Bid Site Visit

CALIFORNIA-GREAT BASIN

REGIONAL CONSTRUCTION OFFICE

TITLE: Trinity River Division GSU Transformer Replacements

SOLICITATION NO.: 140R2024R0002

Questions/Answers during Pre-Bid Site Visit: 2024-08-27

1. There are some concerns regarding the firm-fixed pricing from transformer manufacturers. Is there possibility for adjustable pricing? There might be some sticker shock if not, as the manufacturers are escalating prices for future year values of supplies.

a. BOR is pursuing available alternatives to allow for adjustment of prices and will provide further guidance in a future amendment.

2. What is the track width of the rails at each plant?

a. The centerline-to-centerline distance of rails at Spring Creek Powerplant, Judge

Francis Carr Powerplant, and Trinity Powerplant is 86.25 inches, as stated in Section 49 19 23 – Electrical Power Generation Transformers, Article 1.05A.15.a.

3. Does each plant have a rail rig or a cart to use for moving the transformers out of their bays?

a. No, the plants do not have a means of moving the transformers and will not be provided; the Contractor shall provide cranes or other lifting equipment as needed, as stated in Section 26 05 05 – Selective Demolition of Electrical, Article 1.05A.

4. Which areas can be used for laydown purposes? Will the areas be prepared (cleaned) for construction, or will they reflect the current states?

a. Areas for laydown use are depicted in Section 01 55 00 - Vehicular Access and Parking in Figures 1, 2, and 3. These areas will be cleaned and made available for Contractor use by the time of construction.

5. When removing the transformers from their current locations, is the Contractor allowed to use the yard for demolition space, so long as they are contained? Who is providing containment?

a. The Contractor is to provide containment per Section 01 57 35 – Oil Spill Prevention and dispose of oil per Section 02 87 20 – Recycle or Disposal of Used Oil. The Contractor must demolish the transformer in accordance with Section 26 05 05 – Selective Demolition of Electrical, Article 3.03G.

6. Can we tear apart the transformers in the parking lot? Take out the oil, slice them up, etc.?

a. Per Section 26 05 05 – Selective Demolition for Electrical, Article 3.02.E.4, the existing transformers cannot leave the site until the new transformers are operational.

b. Per Section 48 19 23 – Electrical Power Generation Transformers, Article 3.07.L, the new transformers must be energized for 5-days to be considered complete.

c. Additionally winding samples are required for Degree of Polymerization tests per

Section 26 05 05 – Selective Demolition for Electrical, Article 3.02.E.5.

7. There are some logistic concerns about ordering the transformers: most transformer manufacturers will ship a single transformer at a time. Where are we able to store the transformers as the others arrive? Will it be an issue if the first transformer is sitting in the storage area for a year or more before the others? What happens if there is a failure with the fluid; who is responsible for replacing it?

a. It is stated in the Specifications in Section 48 19 23 - Electrical Power Generation Transformers, Article 1.06.F that at least three (3) transformers are to be shipped at a time to complete installation of one power plant, although they may be shipped separately. Further, long-term storage of the transformers will not be provided, unless authorized by the COR in advance. If there is a failure, a discussion will be held between all parties and a decision made at that time.

b. Per Section 48 19 23 – Electrical Power Generation Transformers, Article 1.06.B, the transformers cannot ship to the site until the Government has approved all factory tests.

8. What are the specifications for the anchoring system?

a. See Specification Section 05 12 73 – Power Transformer Anchorage System for the anchoring requirements, as well as the following drawings:

a. Spring Creek: 416-D-60096 and 416-D-60097

b. Judge Francis Carr: 416-D-60100 and 416-D-60101

c. Trinity: 416-D-60098 and 416-D-60099

b. Please note that, per this Section’s Article 1.04.A.6, the anchorage system design is to allow all transformers the ability to be installed at any power plant. Each site anchorage system may include unique adapters, beams, or arms to allow the transformer to be anchored at the same dimension attachment point at any of the power plants.

9. How do the interface cabinets work at each of the plants?

a. In the Specifications Section 48 19 23 – Electrical Power Generation Transformers, Article 2.08 we defined the difference between the transformer Control Cabinet and the Interface Cabinet.

b. The transformer control cabinet requirements are listed in Section 48 19 23 – Electrical Power Generation Transformers, Article 2.08.A. The control cabinets will be mounted on Segment 4 of the transformer per Section 48 19 23 – Electrical Power Generation Transformers, Article 2.08.G. The transformer interface cabinet requirements are listed in Section 26 05 33 – Raceways and Boxes for Electrical Systems, Article 2.01. The interface cabinets will be mounted on Segment 1 of the transformer per Section 48 19 23 – Electrical Power Generation Transformers, Article 2.08.G.3.a.

c. As part of the design, each transformer must be compatible to be installed at any of the three plants. For this to happen, the transformer control cabinet will travel with the transformer and the interface cabinet will stay with the plant. The demarcation will be between the transformer control cabinet and the interface cabinet. Note that Trinity has conduit that enters from the top while the other two plants have conduit that enters from the bottom; as defined in Section 26 05 33 – Raceways and Boxes for Electrical Systems, Article 2.01.D.3.

10. When was the last time that the Trinity hatch covers were opened and do we have pictures of the inside?

a. Per local facility personnel, there is no known time for when the hatch covers were last opened.

b. Per drawing sheet number 79 and 80, the seismic anchorage system must not impact the hatch cover. Drawing plate number 88 shows the subsurface concrete under the hatch cover.

11. Where are we connecting the neutral grounding cable?

a. Per Section 33 72 26 – Outdoor Jumper Buses, Rigid Bus and Accessories, Article

1.05, the neutral bus design will match what is found at Trinity and will apply to the other plants. All plants will be rigid pipe bus.

12. Will the specifications require a secondary oil containment system?

a. No, secondary oil containment is not required. Please see Section 01 57 35 – Oil Spill

Prevention for containment requirements and note the Spill Prevention, Control, and Countermeasure Plan requirements are listed and should be submitted under RSN 01 57 35-1 for the Spill Prevention Control and Countermeasure Plan.

13. What type of fluid will be specified for the transformers?

a. The insulating fluid will be synthetic ester fluid per Section 48 19 24 – Transformer

Insulating Fluid.

14. What height will the isolated phase bus be modified to?

a. Per Section 26 05 05 – Selective Demolition for Electrical,

a. Contractor to modify bus as needed. The modified isolated phase bus height shall be matched at all three power plants to allow for the same connection heights after construction is complete. Only remove bus as necessary for new transformer configuration. Prevent excessive removal of bus.

b. Coordinate with new isolated phase bus and transformer design for removal extents. See Section 48 19 22 – Isolated Phase Bus and Section 48 19 23 – Electrical Power Generation Transformers.

b. Per Section 48 19 22 – Isolated Phase Bus, design the isolated phase bus connection point to be the same height for all three power plants. All transformers shall have the ability to be installed at any power plant. For modifications to the existing bus, see Section 26 05 05 – Selective Demolition for Electrical.

15. Would it be acceptable for the manufacturer to design the transformers for FR3, but test them with mineral oil at the factory? The transformers would be filled with FR3 at site.

a. Per Section 48 19 23 – Electrical Power Generation Transformers Article 2.04.A, the transformers are to be designed, impregnated, tested, filled on site, and operated with synthetic ester fluid. Alternate insulating fluid for impregnation and/or factory testing is not acceptable.

b. Please also note that FR3 is a natural ester fluid. Please see Section 48 19 24 – Transformer Insulating Fluid for requirements on the specified synthetic ester fluid.