QnAs 4-28-23.docx

Q&As 4/28/23

1. The request is written for replacing the rotating DC exciters and furnish new automatic voltage regulators (AVRs). As mentioned, a typical replacement for an amplidyne/ rheostate AVR with rotating DC exciter is to replace with a new static excitation system, similar to what was done at IBWC’s Amistad hydro plant. Please confirm that IBWC is open to a static excitation system solution as well. We plan to review all the options available to upgrade the current excitation and AVR system.

2. Due to current lead-times of components in the market it may be difficult to complete all work for unit 1 before the end of 2023. Please confirm if the work for unit 1 can continue into 1st quarter of 2024. There would be no need to change schedule for unit 2 and 3. We understand the first unit would be ready until the first quarter of 2024 as the electrical manufacturing companies are busy at this time.

3. The reference to an Automatic Voltage regulator with different tap changers seems out of place. Tap changers are not used for excitation systems, but used with step-up transformers etc. Please clarify. The AVR is used to modify the DC voltage in the current excitation system, but we plan to review all options available in the market to upgrade current system.

4. Please clarify what the PLC throw over/breaker control system refers to. This is not commonly used after an AVR retrofit or static excitation retrofit. We had been conducting upgrades in other electrical equipment in the plant and a new PLC was installed to protect the Generators and Alarm System (annunciator). The PLC works with the INDUSOFT SOFTWARE and pictures will be provided along with the name plates.

5. This item seems to reference that more changes are required in the PLC INDUSOFT software that are not related to the changes to the excitation system. It references 6.9kV switchgear, HV breakers etc. Please clarify. The paragraph also references that a new 125Vdc distribution panel should be furnished. While this is separate from the excitation system, is the intent to include this additional scope with the excitation replacement? Please clarify. Please disregard this item new DC Panel Project will provide this item.

6. Please clarify why the station service would be affected by one unit being retrofitted. Normally the other operating units would provide station service power. Hence, there should be no need for emergency power to be provided. Please clarify. Please disregard this item new DC Panel Project will provide this item.

7. This paragraph references details about a different scope (Motor Control Centers). Is this a left-over from a different contract specification? Please clarify. Please disregard this item new DC Panel Project will provide this item.

8. Clarifications are required to this paragraph. Is it referring to changes to the unit PLC logic that interfaces with the exciter? Of alternatively changes in interfacing with unit protection relaying? Please clarify. The New Upgrade may or may not will require to update the current PLC logic Ladder diagram it’s something the contractor needs to know.

9. Reference to training on Motor Control Centres. Is this also a left-over paragraph from a different RFP? Please disregard this item new DC Panel Project will provide this item.

10. In Section 2.1 paragraph D “Communications and Master Control Panel shall include”, the scope includes the “design of a master control panel” – can you please provide more information about what are the requirements of these master control panels? Additionally, can you confirm that this Master Control Panel is different than the scope specified in the concurrent PWS “Generators Main Control Boards Upgrade”. Disregard this requirement.

11. In Section 2.1 paragraph E requires the “Engineering and Design of a new 125Vdc Distribution Panels'' – can you clarify if the scope is to add new 125Vdc distribution panels for the new excitation system only, or if the scope is to replace also the existing DC panels. If the latter, please provide electrical drawings, layout of the existing panels. Disregard this requirement. This item will be covered with the New DC panel Project

12. Regarding Section 2.1 paragraph H “Electronic Measuring Meter devices in every MCC”, please provide Electrical Drawings and Layout of the existing MCCs . Disregard this requirement. This item was covered with the new MCC project.

13. Also, in Section 2.1 paragraph H “Electronic Measuring Meter devices in every MCC” the requirement states “These (measuring devices) devices shall be the most accurate available in the market” - may we request more specific information regarding the accuracy required? Disregard this requirement. This item was covered with the new MCC project

14. Section 2.3 Testing and Training paragraph C states “training will be scheduled shortly after completion of the Falcon Power Plant Motor Control Center” – please confirm that in this sentence IBWC meant Exciters and Automatic Voltage Regulators instead of Motor Control Center. The training is for the new exciters and AVR control system.

15. Section 2.1.H- mentioned that "if necessary" a 125 Kw temporary generator shall be provided. The question is, is there a specific scenario that IBWC foresees the need of this generator? For example: during demo and installation, or during commissioning.

We ask this question to fairly calculate the cost associated with providing the temporary generator Disregard this requirement. This item will be covered with the New DC panel Project