AC distribution Flashcards
What components are powered from Bus 141?
1A CV PP, 0A VC chiller, 1A AF pp, 1A CS pp, 1A RH pp, 1A SI pp, 1A SX pp, 1A CC pp, 0 CC pp, 0A AB supply, 0A AB exhaust, Bus 131X, Bus 131Z
What components are powered from bus 142?
0CC pp, Bus 132X, Bus 132Z, 1B CC pp, 1B CS pp, 1B RH pp, 1B SI pp, 1B SX pp, 1B CV pp, 0B AB Exhaust, 0B AB supply, 0B VC chiller
What components are powered from bus 143?
Bus 033W, Bus 133U, Bus 133V, Bus 133X, Bus 133Y, Bus 133Z, warehouse/gatehouse, 1A CW pp, 1C CW pp, 0A WS pp, 1A VP chlr, 1A SAC, PZR heaters GRP-A and GRP-D
What components are powered from bus 144?
PZR heaters B/U grp-B, PZR heaters Var grp-C, Bus 134U, Bus 134V, Bus 134X, Bus 134Y, Bus 134Z, 0B WS pp, 1B VP chlr, 1B CW pp, 0A fire pp, 1B SAC, Bus 034R, Bus 034P, Bus 034W, 0A SB chlr, 0A VA chlr
What components are powered from bus 156?
1B RCP, 1B HD pp, 1A FW pp
What components are powered from bus 157?
RSH transformers, 1A HD pp, 1C HD pp, 1A RCP
What components are powered from bus 158?
1C RCP, 1D CD/CB pp, 1B CD/CB pp
What components are powered from bus 159?
1D RCP, 1A CD/CB pp, 1C CD/CB pp, SU fw pp
What are the normal power supplies for busses 141, 142, 143, 144, 156, 157, 158, 159?
SAT- 141, 142, 158, 159
UAT- 143, 144, 156, 157
What interlocks exist to supply power from the ESF to non ESF? 1411 breaker interlocks
- Unit X-tie breaker open 1414
- Non-ESF UAT feeder open 1431
- Non-ESF SAT feeder open 1432
- Cntmt recirc sump interlock reset
- No overcurrent on bus-tie breaker
What are the interlocks to close the SAT feed breaker to bus 141? Breaker 1412
- One of the following breakers open:
- 1414, unit x tie
- 2414, other unit x tie
- 2412, other unit SAT feed breaker
- Sync scope on
- No faults on SAT
- No overcurrent on bus
What interlocks must be satisfied to manually close DG output breaker? Breaker 1413
D/G up to speed and voltage
Syncscope on
Bus energized (Hacker relay energized)
What interlocks must be satisfied to auto close DG output breaker? - example Breaker 1413
D/G speed and voltage ESF to non esf open 1411 1412, 1413, 1414 open no lockouts DG output breaker CS in A/T (Unless surv test sw in TEST)
What interlocks must be satisfied to close a unit x-tie breaker?
Breaker 1414
- One of the following breakers must be open:
- 1412 SAT feeder breaker
- Other unit x-tie breaker 2414
- Other unit SAT feeder breaker 2412
- ESF to Non-ESF bus x-tie breaker open 1411
- Sync scope on
What interlocks must be satisfied to manually close UAT feed? Breaker 1431
- ESF to Non-ESF bus x-tie breaker open 1411
- One generator output breaker closed
- MPT disconnect closed
- Sync scope on
What interlocks must be met to Auto close UAT feed?
Breaker 1431
- ESF to non-ESF bus x-tie breaker open 1411
- One gen output breaker closed
- MPT dis connect closed
- SAT feed breaker CS in A/C
- UAT feed breaker CS in A/T
- SAT feed breaker open 1432
What interlocks must be met to manually close SAT feed? Breaker 1432
ESF to non esf bus x-tie open 1411
Sync scope on
What interlocks must be met to auto close SAT feed?
1432
- ESF to non-esf bus x-tie breaker open 1411
- UAT feeder breaker in A/C 1431
- SAT feeder breaker in A/T 1432
- UAT feeder breaker open 1431
What is RAST? Time delay?
R=Reclose
A=Alive bus
S=Sync check
T=Timed (set @1sec)
Breaker will reclose after 1 sec if bus is alive and in sync
What bus powers the rod drive MGs?
133Y and 134Y
What busses power the jockey pumps?
Jockey A 134 U
Jockey B 133 U
What busses power the RCFC?
131X RCFC 1A and 1C
132X RCFC 1B and 1D
Main power transformer (MPT) ratings
60% capacity each
23.7 to 345KV step up
Forced oil and air cooling (FOA/FOA)
Fans and oil pumps auto start when Q10/Q20 bkr closed
MPT trips
Differential overcurrent*
Overexcitation
Ground overcurrent
Sudden pressure *
- Actuates deluge
Any MPT trip will actuate 86G1A and 86G1B which trips main generator
SAT System aux transformers ratings
100% capacity each
345kv to 4160 and 6900KV
Forced air and natural oil circ cooling (OA/FA)
Fans are manually or thermostatically started
Bladder over oil with Dessicant-dried air over bladder
SAT trips
Differential overcurrent * Instantaneous Ground overcurrent Sudden pressure * Loss of Phase *Actuates deluge
Any SAT trip will actuate 86ST11 and 86ST12 which results in a LOOP
UAT unit aux transformer ratings
100% capacity 23.7kv to 4160 and 6900 v Forced air with natural oil U1 Forced oil U2 Fans manual or thermo controlled Bladder over oil U1 N2 gas over oil U2
UAT trips
Differential overcurrent* Instantaneous Ground overcurrent Sudden pressure* Timed overcurrent
*Actuates deluge
Any UAT trip will actuate 86G1A and 86G1B which trips the main generator
How do GCB fail on a loss of gas pressure or hydraulic pressure?
Fail as-is
The ABB fail open 3-8, 8-14, l0626cb
What is the mode of force to open and close an OCB?
Spring to open
Air to close
6.9KV bus UV
2 of 4 <5268VAC (76%) >=0.8seconds starts AF pumps and if above P7, rx trip
-Any bus w/Voltage at 4920 VAC time sensitive strips all load breakers
6.9KV under frequency
2/4 <57.0 Hz (95%) for 0.4 seconds generates rx trip >P7 and will trip all RCPs
-UF relays are powered from bus and require degrading frequency to actuate. If bus loses power instantly, not UF actuation
4160VAC non ESF UV
2870VAC for 2.0 seconds will trip all load breakers (ABT is within 0.1 seconds so no UV on an ABT)
4160VAC ESF bus degraded voltage
Bus voltage of 3847.5 +-5 for 310 seconds will trip all feed breakers
- degraded voltage relay will immediately trip if its timer is counting and a SI signal occurs
- BAR 1-21-C7/1-22-C7 has operator open SAT feeder breakers at 3160.2VAC
4160VAC bus UV (not slow degraded)
2870VAC will trip all load breakers (except 480vac loads) and auto start EDG. When EDG up to rated voltage and speed, feeders open. 1.8 seconds allows diesel to come up to speed.
4160VAC ESF low degraded voltage
3160.2VAC for 3 seconds will trip all feeder breakers
Diesel generator loading sequence
LOAD STARTED/Time (sec) CV pump/ 0 VC WO pump/0 (U1 only) SI pump/ 5 only if SI signal present RH pump/10 only if SI signal present VC chiller/15 (chiller starts 60 sec after start signal) CS pump/15-18 (only if CSAS present) CC pump/20 SX pump/25 AF pump/35 (A train only) CS pump/40 (will start anytime after 40 sec if CSAS received
TS 3.8.1 requirements
LCO 3.8.1 The following AC electrical sources shall be OPERABLE:
a. Two qualified circuits per bus between the offsite
transmission network and the onsite Class 1E AC
Electrical Power Distribution System; and
b. Two Diesel Generators (DGs) capable of supplying the
onsite Class 1E AC Electrical Power Distribution System.
one power source unavailable weekly power availability within 1 hour and every 8 hours. restore within 72 hours or RICT
One EDG inoperable- both opposite unit DG operable (every 24 hours)and weekly power availability within one hour (every 8 hours). OR diesel surveillance within 24 hours and 14 days to restore.
> = 1 bus w/2 offsite sources out- 24 hours
one edg and 1 bus w/2 offsite sources out- 12 hours
2 dgs inop - 2 hours to restore one
TS 3.8.2 requirements
LCO 3.8.2 The following AC electrical power sources shall be OPERABLE:
a. One qualified circuit between the offsite transmission
network and the onsite Class 1E AC electrical power
distribution subsystem(s) required by LCO 3.8.10,
“Distribution Systems-Shutdown”; and
b. One Diesel Generator (DG) capable of supplying one
division of the onsite Class 1E AC electrical power
distribution subsystem(s) required by LCO 3.8.10.
APPLICABILITY: MODES 5 and 6,
During movement of irradiated fuel assemblies.
If either bus lost or EDG lost:
- suspend core alts
- suspend fuel moves
- take action to suspend positive reactivity adds
- initiate action to restore an offsite power source or Edg
- Declare ltop inop
TS 3.8.7 requirements inverters operating
LCO 3.8.7 Four instrument bus inverters shall be OPERABLE.
APPLICABILITY: MODES 1, 2, 3, and 4.
Restore inverter within 7 days
Enter 3.8.9 if instrument bus is lost
TS 3.8.9 requirements Distribution systems
LCO 3.8.9 The following AC, DC, and AC instrument bus electrical power distribution subsystems shall be OPERABLE for the applicable unit: Unit 1 Unit 2 A. Division 11 AC A. Division 21 AC Subsystem Subsystem 4.16 kV Bus 141 4.16 kV Bus 241 480 volt Bus 131X 480 volt Bus 231X 480 volt Bus 131Z 480 volt Bus 231Z Division 11 AC Division 21 AC Instrument Bus Subsystem Instrument Bus Subsystem Instrument Bus 111 Instrument Bus 211 Instrument Bus 113 Instrument Bus 213 Division 11 DC Subsystem Division 21 DC Subsystem 125 VDC Bus 111 125 VDC Bus 211 B. Division 12 AC B. Division 22 AC Subsystem Subsystem 4.16 kV Bus 142 4.16 kV Bus 242 480 volt Bus 132X 480 volt Bus 232X 480 volt Bus 132Z 480 volt Bus 232Z Division 12 AC Division 22 AC Instrument Bus Subsystem Instrument Bus Subsystem Instrument Bus 112 Instrument Bus 212 Instrument Bus 114 Instrument Bus 214 Division 12 DC Subsystem Division 22 DC Subsystem 125 VDC Bus 112 125 VDC Bus 212 APPLICABILITY: MODES 1, 2, 3, and 4.
AC distribution inop 8 hours
AC instrument bus inop 2 hours
DC bus inop 2 hours
Two AC Dist out and loss of safety function 3.0.3
What conditions required to be met for ABT?
Shut feeder breaker in A/C position
Open feeder breaker in A/T position
No bus lockouts
Only applicable to busses 156, 157, 143, 144 if elec plant in normal lineup.
What are 6.9kv inputs to RPS?
RCP bus UV 5268 VAC 2/4
RCP bus UF 57 Hz 2/4
RCP breaker position
Why are RCPs tripped when UF occurs on 2/4 rcp buses?
To trip the remaining RCPs to divorce them from the power supply and allow coast down on the flywheel. Prevents a DNBR below limit.
Order of preference for power supply to 120VAC instrument buses.
- 480VAC ESF bus via inverter
- 125VDC ESF bus via inverter
- CVT (480V ESF power)
