MFP Turbine Ctrls

Question 1

When are the MFPs forced to speed ctrl?

Answer 1

• Both MS Press xmitters Fail
• Both MFP Hdr # xmitters Fail
• MFP DP Setpoint xmitter Fails
• Other MFP Trip when > 60% Power
• MFP Speed > 5220 (5300) rpm when its forced to speed ctrl

Question 2

What will override MFP Speed Ctrl on U2?

Answer 2

• MFP 1st Stage # Limiter

- Will close down on control valves to prevent excessive 1st stage #. (@ 105# first stage # and 5300 rpm)

Question 3

When is MFP ΔP enabled?

Answer 3

• MFP Speed > 3500 rpm

Question 4

What are the Hardwired MFP trips?

Answer 4

• Manual
• Rx Trip
• SI
• Hi Hi SG Lvl (P14)
• IOPS 110% 5740(5830) rpm
• Thrust Bearing Wear

Question 5

What are the DCS MFP trips?

Answer 5

• Condenser Vacuum Low < 20”(15”) Hg
• Overspeed 107% 5585(5670) rpm
• Loss of suction pressure < 180# for 5 sec
• Lube Oil Pressure Low < 4#(13#) for 5 sec
• Low trip header pressure 800 psi

Question 6

When does the Main Steam to the MFP Automatically open for fast action Main Steam Supply to MFPs in U2

Answer 6

• When MFP steam control valves > 65% open, MS supplies open until control valves < 63%
• When MFP trips, MS to running MFP set to 105#
• Minor perturbation

Question 7

What feeds the Steam Flow input for the ΔP Control for program ΔP?

Answer 7

• Total Steam Flow selected Channel

- No Load Set point

Question 8

What transmitters feed the ΔP Control for actual ΔP?

Answer 8

• UPC-102A/B (Bypass Steam header) (Higher of 2)

- FPC-250A/B (6A FW Htr outlet) (Lower of 2)

Question 9

What happens when a MFP is forced to speed ctrl?

Answer 9

• Remaining MFP shifts to SPEED CONTROL
• SPEED TARGET set to Max (5220/5300) RPM
• RAMP RATE is calculated to bring speed reference to Max in 20 seconds.
• U2: ARV-11/12 setpoint ramped to 105#

Question 10

What parameter tells the MFP that power is > 60%?

Answer 10

• dP setpoint > 110 (U1)/116 (U2) psid