General Flashcards
1
Q
Purpose?
A
- Provides the emergency busses (E1 and E2) with power in the event of a loss of offsite power to these busses.
- In the event of an automatic safeguards actuation the EDG’s will startup.
- EDG’s are essential for the safe shutdown of the plant
2
Q
Design Basis:
A
- The emergency power supply system consists of two Emergency Diesel Generators.
- The systems are kept in standby status at all times, with the exception of when maintenance is being performed on the units.
- Designed to reach rated speed of (900rpm) and voltage (480V) within 10 seconds of the start signal.
3
Q
EDG Description: (load Rating) (with Deepwell)
A
- Generator load rating is:
- 2500KW (continuous)
- Between no more than 2 hours in 24hrs
- 2750KW Not to be exceeded
- No more than 4,000 Amps (Output breaker rating) - 1500Kw
4
Q
EDG can be manually started from:
1 pre-lube
3 not
A
-The RTGB (preform a 4.5 min pre-lube when started from the RTGB.)
- Locally at the following (Will not pre-lube)
- Engine Control Panel (must be in local control)
- Generator control Panel
- Hand-Start Valves
5
Q
EDG Auto-starts
A
-SI Signal
(EDG starts but output breaker to E bus will not close unless UV is present)
-UV on respective E-Bus
(430volts for 10 seconds, trips input breaker to respective bus, DV, degraded voltage, causes UV)
(328 volts is under voltage set point)
6
Q
E1/E2 UV
and
Degraded Grid Voltage
A
- Setpoints: 328V (1/2 UV relays)
- Isolates E-Bus
- Sheds loads except MCC-5/16, MCC-6/18
- Starts EDG
- Starts Blackout Sequencer - Setpoint 430V for greater than or equal to 10seconds, causes UV because:
- Opens normal bus supply breakers
7
Q
SI/UV auto start defeated by?
A
-Local/Remote control switch is in the Local position
8
Q
EDG DC Control power by:
supplies power to (6)
A
-Powered by DP-A(MCC-A) and DP-B(MCC-B)
Supplies:
- Air start solenoids
- Voltage Regulator
- Generator field flash circuitry for the exciter
- Low speed relay
- Pressure switches
- temperature switches
