Bus Duct Cooling

Question 1

What are the Bus Duct Fan auto starts?

Answer 1

• Low Flow (5” H2O decreasing) with C/S in auto

Question 2

What cools the Bus Duct

Answer 2

• TACW

Question 3

What has to be done if both Bus Duct fans fail?

Answer 3

• bus loading must be reduced to a maximum of 10,000 amps per phase (approx. 38-40% power)

Question 4

Which unit has the Deionizing Baffle and what is it for?

Answer 4

• Unit 1 and they prevent transferring ionized air (arcing) from one phase to another (they are between the main transformer connections)

Question 5

What is the bus duct flow path for U1?

Answer 5

1. Cooler
2. Fan
3. Supply Via Middle Duct
4. Deionizing baffles
5. Return in North and South ducts
6. Interplenum

Question 6

What is the bus duct flow path for U2?

Answer 6

1. Cooler
2. Fan
3. Out South duct to generator terminals
4. MT Dampers
5. Return in North and middle ducts
6. Interplenum

Question 7

How many Bus Duct Cooling Fans do we need to operate at 100% power?

Answer 7

• 1 Bus Duct Cooling fan needed for 100% operation

Question 8

What is the Max Design Temp of bus ducts?

Answer 8

• High High Limit is 221°F (105°C)
• Maximum design temp is 180°F (82.2°C)
• High Alarm at 174.2°F (79°C)

Question 9

What are the U1 and U2 Bus Duct Loads?

Answer 9

• Main Gen Connections
• Bus PTs
• MT Connections
• UAT Connections