Class 125 VDC Control Power (PK) Flashcards
Is PK grounded or ungrounded?
Why?
ungrounded with ground detection system
Ungrounded system more reliable because a ground would be required on both the positive and negative bus to significantly degrade the system.
alarm in CR
white light locally
How long will the PK batteries maintain full loading?
Battery can maintain loads for 2 hours at a minimum temperature of 60 degrees F.
What does the DG need PK for?
control power
field flashing
What happens to the DG on a loss of PK?
can’t start without PK
If running, DG will trip and output breaker will stay closed
What happens to AFA on a loss of PK?
trip on overspeed
What SDC isolation valves does PK provide power to?
SIC-UV-653
SID-UV-654
through inverter (DC power to AC motor)
What is the limitation for the PK busses when operating SIC/D-UV-653/654?
battery and charger must both be connected to the bus
Can the PK indications and controls be isolated from the control room?
‘B’ train has the App R disconnect switch
B/D charger also has the App R disconnect
Where does PK get power from?
PH
Can PK control centers be paralleled via the swing charger?
No, break before make
mechanical interlock doesnt allow it and you cant connect trains together
Where are the PK Battery Breakers normally operated from?
CR
can be done locally
What SEIS alarms are available for PK?
white light only
battery breaker not closed or inop
what ventilation fans are provided for the PK Battery rooms?
normal and essential fans
On a loss of normal cooling to the PK battery rooms, what provides cooling?
ESF Switchgear room AHU
When would the ESF Equip. Room AHU be supplying the DC equipment rooms?
SIAS or LOP
How can you tell if we lost a charger to the PK bus regarding voltage and amperage?
voltage closer to 130
battery amps to the right (discharging)
Each battery charger designed to restore battery from minimum to normal steady state within how long?
12 hours
What could bring this alarm in?
This annunciator indicates either a loss or problem with a
particular 125 VDC Control Center or Distribution Panel.
Inputs to this alarm include:
* PKA-M41 under voltage, ground or breaker trip
* Battery Charger problems including over or under
voltage, AC supply voltage low, charger failure or
reverse current
* Distribution Panel overload also inputs to the
annunciator
What could bring this alarm in?
This annunciator indicates either a loss or problem with a
particular 125 VDC Control Center or Distribution Panel.
Inputs to this alarm include:
* PKB-M42 under voltage, ground or breaker trip
* Battery Charger problems including over or under
voltage, AC supply voltage low, charger failure or
reverse current
* Distribution Panel overload also inputs to the
annunciator
What could bring this alarm in?
This annunciator indicates either a loss or problem with a
particular 125 VDC Control Center or Distribution Panel.
Inputs to this alarm include:
* PKC-M43 under voltage, ground or breaker trip
* Battery Charger problems including over or under
voltage, AC supply voltage low, charger failure or
reverse current
* Distribution Panel overload also inputs to the
annunciator
What could bring this alarm in?
This annunciator indicates either a loss or problem with a
particular 125 VDC Control Center or Distribution Panel.
Inputs to this alarm include:
* PKD-M44 under voltage, ground or breaker trip
* Battery Charger problems including over or under
voltage, AC supply voltage low, charger failure or
reverse current
* Distribution Panel overload also inputs to the
annunciator
