Main Power - .5 Flashcards
What do AX501 and BX501 supply?
1E 4160VAC Busses
What do AX502 and BX502 supply?
7.2KV busses.
What do AX503 and BX503 supply?
Circ. Water.
Generator Lockout Signals w/ output bkr closed.
- Gen loss of field* (reg. and b/u)
- Gen out of step* (R&B)
- Gen field overvoltage (10 sec TD) ( Reg)
- Gen field overexcitation (Reg)
Generator lockout signals.
- Alterex Exciter Diff O/C *(Reg)
- Gen (Phase) Diff O/C* (Reg)
- Gen O/C (b/u)
- Gen Neg Phase Sequence (Reg)
- Gen Reverse Power:
Reg.-2.5 sec w/ turbine trip
B/U-30 sec w/o turbine trip
* Also trips stator water cooling pumps on Gen Diff O/C
Generator Lockout Auto Actions
(Also trips stator water cooling pumps on gen diff o/c)
- Trip Gen Output Breaker (2-6 and 6-5)
- Trip Exciter Field Breaker
- Trips the Turbine
- Initiates Breaker Failure Protection (2-6 and 6-5)
- Overhead Alarms and Process Computer Alarms
Unit Lockout Signals
- Unit Diff O/C (Regular & Backup)
- Gen Neutral O/C (Regular & Backup)
- Gen Neutral O/V (Backup Only – Shutdown Protection)*
*Both output breakers must be OPEN to activate.
Unit Lockout Auto Actions
-Main Transformer Cooling Fans Trip
-Stator Water Cooling Pumps Trip
-Trip Gen Output Breaker (2-6 and 6-5)
-Trip Exciter Field Breaker
-Trips the Turbine
-Initiates Breaker Failure Protection (2-6 and 6-5)
-Overhead Alarms and Process Computer Alarms
Load Break Disconnects indicator colors.
- Gas Pressure Indicator – Gray (normal), Red (low pressure)
- Interrupting Unit Targets – Gray (normal), Yellow (open)
What is BKR fan out?
If a BKR is suppose to open but fails to, the next BKR in line will open.
Disconnect and ground interlock.
Both cannot be closed at the same time.
SLP 3 & SLP 4 function
Supplies power to to the site ring bus.
Normal 13.8KV disconnect and BKR lineup.
- All disconnects are normally closed except for 13T30 and 24T30.
- All BKRs are normally closed except for 2-3 and 7-8.
13.8KV disconnect interlocks.
1T30, 3T30, and 13T30 (2T30, 4T30, and 24T30) are key interlocked such that only 2 can be closed at one time.
What causes a station power transformer lockout?
Differential overcurrent.
13.8KV BKR interlocks.
- 2-3 (7-8) breakers cannot be closed unless either 1-2 OR 4-5 (6-7 OR 9-0) breaker is open.
- The breaker that was opened can be reclosed once the 2-3 (7-8) breaker is closed.
500KV 1-5 and 1-3 feature .
1-5 and 1-3 breakers have an auto re-close feature.
Main transformer cooling.
There are 3 groups of fans with 1 normally running. 2 and 3 run based on high oil temp.
Isophase H2 monitors.
Alarm if H2 exceeds 4% but fails downscale in this condition.
Tap changer operation.
Do not operate when energized, it has a potential for personnel injury.
Main turbine turning gear requirements.
MG output breakers (2-6 and 6-5) open, or
MG disconnect (52x60) open.
What does the breaker emergency trip handle do?
Removes control power.
How can you remove control power from a (a) 500KV breakers and (b)Load Break Disconnects and (c)13.8 KV breakers?
(a) Control power can be removed by operating the toggle switch located on the emergency trip handle
(b) Control power can be removed by opening the toggle switch on the inside of the enclosure
(c) A toggle switch(interlocked with the emergency trip handle) removes DC control power to the breaker
