Term
Substations
Describe the 345KV breakers. |
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Definition
-All but 8N11 hydraulic operated w/ spring assist.
-8N11 is air open/spring shut.
-Low oil pressure <76#.
-Low-low <72# (prevents trip/close).
-8N11 <198# prevents open/close.
-All have cycling heaters. |
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Term
Substations.
Describe the 230Kv breakers. |
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Definition
-OCBs.
-Hydraulic close/spring open.
-<1600# prevents closure.
-Can still trip. |
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Term
Substations
Describe the 3N4 to 3N5 interlock. |
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Definition
-Supply to 2R transformer.
-3N4 cannot be closed if 3N5 is closed. |
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Term
Substations
Describe what happens if 3N4 opens. |
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Definition
-Both recirc pumps trip.
-Both circ water pumps trip.
-Loss of either 11/12 bus. |
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Term
| Substations Describe the cooling tower substation. |
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Definition
| -Buss' 17 & 18 (13.8KV). -Has load centers 5 & 6 (4KV). -Powered from 1ARS and through 6 transformer. |
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Term
Substations
Describe the breaker and a half scheme. |
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Definition
-3 breakers share circuit.
-Any 1 can be open and still maintain both circuits in service. |
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Term
Substations
Describe breaker auto reclosure modes. |
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Definition
-High speed or instantaneious.
-Synchronous mode (3-6 sec delay).
-Delayed reclosure (about 15 sec delay). |
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Term
Substations
Describe auto-sectionalizing. |
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Definition
-Isolate faulted equipment once circuit breakers have tripped.
-Circuit breaker opens to denenergize faulted equipment.
-Motor operated disconnect opens to isolate equipment.
-Circuit breakers re-close once fault is isolated. |
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Term
Substations
Describe breaker failure relay. |
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Definition
-Sensed by detecting current flow after receiving breaker trip signal and breaker did not open.
-If current is sensed after 12 cycles after breaker trip, breaker lockout is actuated.
-All surrounding breakers to trip and all surrounding busses to lockout. |
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