DIGITAL TURBINE CONTROL SYSTEM (DTCS) Flashcards
What happens when the header pressure error exceeds 40# for 5 seconds?
The turbine bypasses DTCS and goes to HAND control.
What is the rate of change (R.O.C.) when the load set is adjusted in LOCAL?
The load reference increases at a rate of 5%/min.
What does Mark V Limiting do to DTCS control?
It transfers DTCS to LOCAL control.
What happens when Mark V limiting conditions clear?
DTCS returns to REMOTE if it was previously in REMOTE.
What are the stator coolant parameters for DTCS?
Flow rate: 381-400 gpm; Outlet temperature: 80-82°C.
What triggers Power Load Unbalance protection?
Turbine load exceeds generator load by 40%, and generator load changes by 100% in 35 milliseconds.
What sequence occurs during Power Load Unbalance actuation?
CVs and ICVs FAST CLOSE, load reference signal set to 3%, runs back at 150%/min, ICVs reopen after 1 second, CVs reopen after unbalance clears (<40%).
What is the purpose of Valve Position Limiting?
It prevents CVs from opening further than 105% of the setpoint.
What is the setpoint for Main Steam Pressure Limiting (MSPL)?
MSPL actuates on low main steam header pressure <800# and is normally disabled due to a non-redundant sensor.
What happens during Generator Closing Spurt?
Load auto increases to 2% at 50%/min for 5 seconds, then transfers to ICS.
What triggers Intercept Valve actuation?
Leaders (1/3/5) positioned 10% above reference for 20-40% load rejection.
What happens during Intercept Valve actuation?
All 6 IVs FAST CLOSE, valves released for speed control after 1 second.
What is the function of Mechanical/Electrical Lockout Valves during testing?
If a trip condition exists, the lockout valve is released to ensure the turbine trips.
What happens during Control Valve Testing?
First Stage Pressure Control (SPF) is active, sending a highly gained signal to the remaining 3 CVs to open and maintain 1st stage pressure.
What is required for Electrical Trip Solenoid valves to trip?
Both solenoid valves must be de-energized.
