Electrical Distribution Flashcards
What is the auto transfer logic for the Startup transformers?
- Transformer available (no SU 1 LO, no undervoltage, not in PTL)
- No A-1 or applicable bus Lockout
- Transformer selected or other transformer not available
- Gen LO and SU2 breaker open or SU2 LO and unit aux bkr open
- In sync (fast transfer) or UV (slow transfer)
What are the power sources for switch yard control power?
- Normal: 22kv off tertiary winding through 480v xfmr
- Auto Xfer: B-3
- Man xfer: B-6
What is the purpose of dynamic disturbance recording panel (C002)?
Monitor and record potential grid disturbances. (Provides no control functions)
What will cause a startup 1 transformer lockout?
1) phase volt differential
2) neutral over current
3) sudden gas pressure
4) Volt reg LO
5) Auto xfmr LO
What are the power sources for RCPs?
H-1: A & C
H-2: B & D
What provides DC control power to H bus feeder breakers? Load breakers?
Feeder: D-46
Loads: D-11/21
What functions do the DC control breakers in breaker cubicle provide?
Control power and protective relay functions
What causes a SU2 load shed and what occurs?
A-1 OR A-2 tie on
H-1 & H-2 tie on
Trips: - RCPs (Trips A & D)
- Cond pumps (A C B)
- Htr drain pumps (Both)
- CW Pumps (B D A C)
- Main chillers (Both)
What is the effect of a Lockout and Undervoltage condition on a bus?
- LO causes feeder breakers to open and prevents close of them
- UV causes load breakers to open
What is the logic to manually close A-309/A-409?
- No A-1/A-3 LO
- Sync switch on
- Sync check closed
- HS Closed
(If A-3 dead, must hold close until UV clears)
What causes A-309/A-409 breakers to trip?
- A-1 or A-3 LO
- Phase directional OC (Protect diesel with A-1 closed and EDG output bkr closed)
- Phase directional Ground
- A-3/A-4 or B-5/B-6 UV
What will cause EDG output breakers (A-308/A-408) to auto close?
- No UV on EDG
- breaker not in PTL
- No A-3 LO
- A-310/410 and A-309/409 open
A-3/A-4 UV (2 seconds < 2450 V)
B-5/B-6 UV (8 seconds < 429 V)
What will cause EDG output breakers to trip?
- Loss voltage regulator
- EDG LO
- A-3 LO
- A-308 closed, GEN LO, and UA feeder closed (protects the diesel)
What causes A-3/A-4 cross-tie breakers (A-310/410) to trip?
- ES
- A-3 LO or UV
- Overcurrent
- If A-3/A-4 powered from A-1/2 or EDG and opposite cross-tie breaker closed (3 of 4 breakrs closed)
What is the voltage band for B-5/B-6 and what are effects on equipment when operating outside of these limits?
460-500 Volts
Low Voltage - increase in amperage resulting in overheating of motors
High Voltage - results in magnetic portions of motors into saturation and possible overheating