Term
480V
Describe the load centers with cross ties. |
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Definition
-Auto crossties.
-LC-101 to LC-102.
-LC-107 to LC-108.
-LC-102 to LC-109.
-Manual crosstie only between LC-103 to LC-104. |
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Term
480V
Describe which LC the 13DG feeds into. |
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Definition
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Term
480V
Describe the LC-101/102 transfer scheme. |
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Definition
-The LC-101/102 tie-breaker auto closes if:
-If either transformer feeder breaker opens on anything but fault.
-And the opposite LC transformer feeder breaker is closed.
-And the LC-109 to LC-102 tie breaker is open. |
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Term
480V
Describe the LC-103/104 transfer schemes. |
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Definition
-Not an automatic transfer scheme.
-Manual only.
-2 tie breakers, the breaker from the LC-104 must be shut first.
-Associeated LC tie breaker trips if its associated bus (15 or 16) undergoes an essential bus transfer. |
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Term
480V
Describe the LC-102/109 transfer scheme. |
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Definition
-The tie-breaker auto closes if in auto and:
-Either transformer feeder breaker opens on anything but fault.
-And the opposite transformer breaker is closed.
-And the LC-101/102 tie breaker is open. |
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Term
480V
Describe the LC-107/108 normal transfer scheme. |
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Definition
-The tie-breaker will auto close if in auto and:
-Either transformer feeder breaker opens.
-And the opposite transformer feeder breaker is closed.
-And the dead buses lockout relay is not tripped.
-This transfer is will take less than 10 seconds. |
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Term
480V
Describe the alternate LC-107/108 transfer scheme. |
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Definition
-If loss of volts on LC-107 is detected and sustained for 10 seconds then the 13 DG starts.
-About 12 seconds for 13DG to reach rated voltage and speed.
-Then both feed breakers to LC-107 (normal and x-tie) trip open.
-Then 13DG output breaker closes.
-Then now that LC-107 is powered by 13DG if LC-108 feeder breaker is open.
-And if LC-108 has lost voltage for 10 seconds.
-Then the LC-107/108 tie breaker auto closes. |
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Term
480V
Describe the essential MCC-133B/143B (swing bus) transfer scheme. |
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Definition
-Swing bus normally powered from LC-103.
-Auto transfers to the LC-104 power supply if:
-Loss of voltage sensed for 12 seconds (provides time for esssential bus transfer to 1AR or EDG).
-If the 11EDG is already supplying Div I power a swing bus transfer will happen on over/degraded voltage and over/under frequency.
-No auto transfer back. |
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Term
480V
Describe 480V load shed on essential bus transfer. |
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Definition
-All essential bus loads except LC-103 and LC-104.
-Shed of all non-essential loads on LC-103 and LC-104.
-Trip of associated LC tie breaker.
-Initiates 15-cycle time delay. |
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Term
480V
Describe in detail the 480V load shed on essential bus transfer. |
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Definition
-MCC-131/141.
-MCC-132/142B.
-LC-103 tie to LC-104/LOC-104 tie to LC-103. |
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Term
480V
Describe ECCS load shed with normal power. |
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Definition
-If from 2R or 1R.
-Sheds drywell cooling recirc fans.
-Sheds RHRSW pumps. |
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Term
480V
Describe ECCS load shed if powered from 1AR or EDGs. |
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Definition
-11/12 CRD pumps.
-11,13/12,14 RHRSW pumps.
-VRF-1,3/2,4 (vent recirc fans).
-11/12 fuel cooling pumps.
-11/12 RBCCW pumps.
-15 air compressor (div I).
-12SW pump (div II). |
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