ASD Flashcards
What is the purpose of ASD?
Provide pulse width modulated output at the correct frequency and voltage to drive the RR Pumps
What is the input power for the ASD?
Bus 21/22; 31/32 - 4kV into transformer cabinet
Bus 25/26; 35/36 - into Dist. Panel - UPS - PLC Controls
What does the ASD Transformer Cabinet do?
Steps down 4kV voltage to 750VAC for use by power cells
What component of the ASD acts as the “Brains”?
FPC - Fuse Pre-charge Cabinet
What is the purpose of the ASD UPS?
provides 120VAC from the 480VAC DP to the PLCs and NXGs.
Contains battery for short term transients and internal bypass if UPS fails to send DP power directly to PLC
What happens on a failure of ASD UPS 1?
If completely fails and no battery power supplied, the other UPS offers redundant power supply
What powers the ASD Remote IO and what are their purpose?
THey are powered by the Computer UPS and ESS feed for control room indication, remote control cabinets, and basic descriptipn.
Where are the ASD Cabinet Keys located?
Input Cabinet in a lockbox
How many PLCs and NXGs are there per ASD?
2 FPC Cabinets per ASD DRIVE - each with 2 PLCs (A&B) and NXGs (A&B)
What happens on a failure of A NXG? Failure of B NXG?
A Failure - transfers to B
B failure when on B - ASD Trip
What happens to ASD if Fiber Optic Switching Board Fails?
ASD Trip on loss of communication - One of only non-redundant features
What is the purpose of the ASD Pre-charge function?
Allows slowly building in 480VAC instead of direct admission of 4kV to extend power cell life.
If the ASD Local HMI is in local control, what are the conditions in the COntrol Room?
ASD cannot be controlled from MCR, speed hold is put in.
NONE OF RUNBACKS or SPeed Holds in MCR work
How many power cells are there? What is the input voltage?
How many are REQUIRED for FULL power operation?
How many cells lost will cause an ASD Trip?
12 total - 4 per phase - input 750VAC turned into 1000vdc by IGBT
3 cells per phase requried for FULL POWER
ASD trips on 4 cells lost in 1 phase OR 7 total bypassed
What happens on an ASD Power Cell Bypass?
ASD disconnects motor, bypasses cell, re-manipulates cood cells, catchs motor as it is slowing down, and speed hold put in
WHOLE THING takes ~250ms and 6% speed lost
ASD trips if cell can’t be bypassed
What are the required conditions for the ASD Relay cabinet?
The relays work on a 2/3 voting logic to trip. If 2 out of 3 are lost, it will trip. - powered by 125vdc at 4kv Bus - depending on division.
How does the ASD Coolant System Function?
2 pumps - powered off Bus 25/26 with surge tank, temp reg valvs, and bypass valves. cabinet contains deionizer on exterior.
Radiators external to Trailer.
How many ASD Coolant Pumps are normally running?
What conditions cause a pump trip and what happens next?
Normally 1 of 2 running. will trip on loss of power or low flow on running pump.
Standby pump starts. If both pumps lost AND a power cell fault or Xfrmer hi temp - ASD TRIP
How does conductivity affect the ASD Coolant system?
No conductivity trip, but low conditions required to start.
When do the ASD Coolant Fans start?
Auto start based on PLC input. If PLC fails, Fans turn on
What conditions of the ASD Coolant Surge tank induce an ASD Trip?
Lo and Lo-Lo level cause ASD trip
If the ASD Coolant Trmp Reg valve fails, what is done?
Motor Operated Bypass goes full open
What are the Key ASD Trips - associated with 4kV power source?
ATWS Logic (1200psig Rx Press; -59” Rx Level for 9 sec)
RPV Lo Lo Level (-59” from ATS)
LPCI Loop Select
Suction Vlv <90% Open
Disch. Vlv <90% Open
2/3 Relay protective relay trip (DFR, MMR, Basler)
Bus UV/Overcurrent
What are the Key ASD Trips from ASD components?
7 power cells total or 4 in one phase bypassed
Failure to bypass failed power cell
Both NXG failure (or just B if on B)
Lo and Lo-lo level in surge tank
Both coolant pump failed AND power Cell fault OR xfmr thermal alrm
Motor Overspeed
What happens to ASD On loss of ESS?
Loss of Anti-Cav Runback Logic
Loss of I/O Cabinets on loss of Computer UPS
What happens to ASD on loss of COmputer UPS?
Loss of I/O Cabinets when ESS also lost
What happens to ASD on loss of single 480VAC? source?
minimal due to redundance
What happens to ASD on loss of 125vDC?
Loss of control power and backup relay protection
What is the ASD Coolant Pump setpoint?
<90gpm or fault on running pump (also seen if loss of power to running pump) the pumps swap
