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Weeks 1 & 2 Systems > Electrical Distribution > Flashcards

Electrical Distribution Flashcards

1
Q

What is the auto transfer logic for the Startup transformers?

A
  • 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)
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2
Q

What are the power sources for switch yard control power?

A
  • Normal: 22kv off tertiary winding through 480v xfmr
  • Auto Xfer: B-3
  • Man xfer: B-6
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3
Q

What is the purpose of dynamic disturbance recording panel (C002)?

A

Monitor and record potential grid disturbances. (Provides no control functions)

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4
Q

What will cause a startup 1 transformer lockout?

A

1) phase volt differential
2) neutral over current
3) sudden gas pressure
4) Volt reg LO
5) Auto xfmr LO

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5
Q

What are the power sources for RCPs?

A

H-1: A & C

H-2: B & D

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6
Q

What provides DC control power to H bus feeder breakers? Load breakers?

A

Feeder: D-46

Loads: D-11/21

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7
Q

What functions do the DC control breakers in breaker cubicle provide?

A

Control power and protective relay functions

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8
Q

What causes a SU2 load shed and what occurs?

A

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)
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9
Q

What is the effect of a Lockout and Undervoltage condition on a bus?

A
  • LO causes feeder breakers to open and prevents close of them
  • UV causes load breakers to open
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10
Q

What is the logic to manually close A-309/A-409?

A
  • No A-1/A-3 LO
  • Sync switch on
  • Sync check closed
  • HS Closed

(If A-3 dead, must hold close until UV clears)

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11
Q

What causes A-309/A-409 breakers to trip?

A
  • 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
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12
Q

What will cause EDG output breakers (A-308/A-408) to auto close?

A
  • 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)

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13
Q

What will cause EDG output breakers to trip?

A
  • Loss voltage regulator
  • EDG LO
  • A-3 LO
  • A-308 closed, GEN LO, and UA feeder closed (protects the diesel)
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14
Q

What causes A-3/A-4 cross-tie breakers (A-310/410) to trip?

A
  • 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)
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15
Q

What is the voltage band for B-5/B-6 and what are effects on equipment when operating outside of these limits?

A

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

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16
Q

Why do we have a B-5/B-6 undervoltage bypass and how long is the time delay associated with it?

A
  • The bypass is used to starting RCPs due to large amount of starting current and lowering of 480V bus voltage.
  • The time delay is 20 seconds.
17
Q

What is the low voltage alarm for D-01/D-02?

A

< 105 Volts

18
Q

What are the D-01/D-02 ground alarms and what actions are required when these values are met?

A
  • Voltage on either meter 20 - 50 V -> Initiate CR
  • Voltage on either meter < 20 V -> CR, contact engineer, bridge call and callout maintenance
19
Q

What are the power supplies for the battery chargers?

A

D03A - B-51

D03B - B-57

D04A - B-61

D04B - B-65

20
Q

What is the purpose of the 120V AC electrical distribution system?

A

Provides an uninterrupted 120 V AC to important systems and indications (RPS, ESAS, EFIC, etc)

21
Q

What causes vital inverter to swap over to AC source?

A
  • Output voltage low
  • Output current Hi
  • Inverter failure
  • Low DC Input (Y-41 only)
22
Q

Which inverter supplies C540?

A
  • Y-22 or Y-25
23
Q

How is the autotransformer constructed and what does it supply?

A

-The autotransformer consists of 3 windings. The primary winding is 500 KV, the secondary winding supplies 161 KV Ring bus to SU2, and the 3rd 22 KV tertiary winding supplies SU1 and SU3 provides DC control power to the switchyard.

24
Q

What does the term “breaker and a half” mean?

A
  • This term refers to the use of 3 breakers to supply 2 loads. One breaker is shared between the 2 instead of 2 seperate breakers for isolation.
25
What breakers are affected during ESAS condition (10 bkr logic)?
- UA feeder breaker opens (2 breakers) - 4 breakers from A-3/4 to B-5/6 close - 4 cross-ties between A-3/A-4 and B-5/B-6 open (ES 1 affects red train side and ES 2 green train)
26
What is the anti-pump feature associated with breakers and how is it cleared?
- Anti pump feature is always enabled and prevents conflicting signals from cycling the breaker open and closed. - Taking the HS to PTL will clear the anti-pump
27
When do closing springs charge on a 480 V breaker? 4160 V?
480 V - Charge when breaker opens 4160 V - Charge when breaker closes
28
What feature are the Gen Output breakers equipped with to prevent overspeed of main turbine?
Time delay to open on GEN LO
29
What will occur if LOOP and A-310/410 cross-tie breakers are closed?
A-3/A-4 will receive UV which will trip A-309/409 and A-310/410 resulting in EDGs starting and tying on.
30
(T or F) Main transformer cooling groups are interlocked off given a generator LO.
True - interlocked off to prevent buildup of static charge as oil cools off
31
What are the power sources for transformer cooling groups?
B-32/B-42 backup (2B-42 for SU2)
32
What would occur if generator lockout occurs, but unit aux feeder breaker fails to open on A-1?
A-1 lockout and UV would strip all buses, EDG1 would start and tie on to supply A-3. A-2 would be supplied from SU1.
33
How is selective tripping performed?
Overcurrent trip setpoints and time delays
34
What interlock associated with A-3/A-4 and B-5/B-6 cross-tie breakers prevent closing them?
If one cross tie breaker is closed and attempt is made to close the other the first cross-tie breaker will open (only 3 or 4 breakers can be closed unless cross ties are held closed and manually open the breaker supplying power)
35
What occurs when #1 EDG tied on to A-3 paralleled to grid and GEN LO occurs?
EDG output breaker will open to protect diesel, fast transfer to SU1.
36
What AC sources are required per TS 3.8.1 and applicability?
- 2 offsite power sources - 2 EDGs - Modes 1 - 4
37
What sources are required per TS 3.8.2?
Modes 5 and 6 during fuel movement - 1 offsite power source - 1 EDG
38
What are the power supplies for CFW Pumps?
P-805A: London Line P-805B: A-1
39
Draw the power triangle and equation for Power Factor?

Weeks 1 & 2 Systems (6 decks)

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