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28 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Main power purpose |
The main power system distributes the electrical output from the main generator to the AC electrical distribution system and the pennsylvania-new jersey-maryland (PJM) power grid. Voltage is stepped up from 25kv at the main generator output (main power transformers) to 500kv for distribution to the PJM grid via the Red Lion and New Freedom transmission lines and the line to the Salem 500kV switchyard. Station power transformers reduce the 500kV to 13.8kV for station use |
obj 1 |
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Main power transformers purpose |
Step up main generator output voltage from 25kV to 500kV for application to the 500kV switchyard. |
obj 2a |
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Main generator disconnect (52x60) purpose |
Provides isolation capability for the main generaotr and main power transformers from the 500kV switchyard, allowing the 500kV switchyard to remain in a ring configuration. |
obj 2b |
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What happens to an SF6 breaker at the low pressure cutouts (high pressure gas)? What is the setpoint? What is the required action? |
Low pressure alarm (high pressure gas system). Alarms at 250 psig @ 70°F (Based on graphs in HC.OP-SO.MH-0001) One switch for each pole of the breaker. Must be reset at breaker annunciator panel. Low pressure cutout (high pressure system) 240 psig @ 70°F Opens breaker closing control circuit and trips the breaker if the breaker is closed. This ensures the breaker is opened while there is sufficient high pressure SF6 gas for arc suppression and quenching. |
objective 5a
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What happens to an SF6 breaker at the low pressure cutouts (low pressure gas)? What is the setpoint? What is the required action? |
Low pressure alarm (low pressure gas system). Alarms at 45 psig @ 70°F (Based on graphs in HC.OP-SO.MH-0001) must be reset at breaker annunciator panel. Low pressure cutout.(Low Pressure system) 40 psig @ 70°F In series with starter for the compressor. Prevents compressor from trying to maintain high pressure system resulting in the loss of all gas. Trips the breaker if the breaker is closed. The breaker is tripped before dielectric strength is impaired. |
objective 5b
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Identify the purpose of the SF6 high pressure gas |
The high pressure SF6 gas, stored in a gas receiver, is used for arc quenching during breaker opening operations.
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objective 4a
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Identify the purpose of the SF6 low pressure gas |
The low pressure side (within the interrupter heads) is used as the insulating medium for the breaker |
objective 4b
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Identify the purpose of the 500kV switchyard and breakers
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The purpose of the 500KV circuit breakers is to provide fault isolation of a transmission line without interrupting power to the operable lines. |
Objective 2c
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From memory summarize/identify the interlocks associated with the Main Power System that are required to enable turning gear operation |
Both Generator Output Breakers (500Kv Bus BS6-5 and BS2-6) are open. OR #1 Generator Main Trans 500Kv Disconnect (52X60) is open AND DC Control Power for the Disconnect Motor is available. |
objective 13
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Identify/explain the purpose/function of the following associated with Load Break Disconnects (1T60, 2T60, 3T60 and 4T60). a. Red target on the gas pressure indicator. b. Yellow indicator on the interrupting unit target c. Interlock between the handwheel cover and the motor control. |
a. Red target indicates low SF6 Gas pressure b. Yellow - internal contacts are open c. Permits electrical operation without affecting the position of the Load Break Disconnect, or to permit manual operation of the Load Break Disconnect |
objective 8
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Summarize the purpose/function of the circuit switchers
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The load break disconnect is an in-series circuit breaking interrupter used to supply the station power transformers for switching and transformer protection
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objective 2f
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State the purpose of the ground switches
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The purpose of the ground switches is to provide a mechanism for grounding bus sections for personnel safety during maintenance
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objective 2d
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When should the ground switches NOT be closed-in
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Ground switches should never be closed-in on an energized bus. When repositioning the ground switches in either direction (open or close) the operator will operate the crank at a steady rate.
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objective 6
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What is the purpose of the disconnect switches |
The purpose of the disconnect switches is to provide a mechanism to isolate each of the SF6 circuit breakers |
Objective 2d |
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Summarize the purpose/function of the SF6 compressed air system
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An SF6 gas compressor, located on phase B mechanical housing (middle housing), provides the motive force for the high pressure gas. It reclaims the gas from the low pressure side and discharges to the HP gas receiver. Air Receivers, one per phase, store air to be used as the pneumatic force for breaker operation during the closing cycle. Pneumatic pressure is used for breaker closing operation. Air pressure is applied to a control piston. Operation of the control piston will result in breaker closure |
objective 4g |
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Summarize the interlock between the breaker emergency trip hand and control power for the breaker SF6 and oil circuit breaker. |
When tripped, the emergency trip handle also trips power to the breaker control circuitry. Tripping one-phase results in a "pole disagreement" and automatically trips the other two associated phases. Control power must be reset by opening the breaker control housing and repositioning the control power toggle switch |
objective 14
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State the purpose of the station power transformers |
The purpose of the station power transformers is to supply power from the 500KV switchyard to the 13.8KV ring bus for station |
objective 2g
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State the purpose of the disconnect switches
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The purpose of the disconnect switches is to provide a mechanism to isolate sections of the 13.8KV ring bus for maintenance
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obj 2d
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Summarize / explain the interlock associated with 1T30, 3T30, and 13T30 (2T30, 4T30, and 24T30) |
Disconnects 4T30, 2T30 and 24T30 are interlocked such that only two of the three disconnects can be closed at one time. This interlock prevents paralleling the station power transformers through the 13.8KV switchgear. Disconnects 1T30, 3T30 and 13T30 are interlocked in a similar manner. All 13.8KV disconnect switches are mechanically interlocked with their associated ground switches. The ground switch cannot be closed until the disconnect is open and/or the disconnect cannot be closed until the ground switch is open.
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Objective 10
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State the purpose of the 13.8kV ring bus
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Purpose - the 13.8KV ring bus provides the electrical tie between the 500KV switchyard and the station AC electrical distribution system. |
Objective 2e.
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State the purpose and voltages of the station light and power transformers
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#1/2 SLP are 13.8kv/208/110v - switchyard utility use. #3/4 SLP 13.8/13.8. - 13.8KV supplies power to the island substation ring bus |
objective 2h / 2i / 7
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Explain why #T60s are NOT manually closed while energized
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Manual closing of an energized Load Break Disconnect is prohibited due to the possibility of closing into a fault
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Objective 9
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Identify the four automatic actions which will occur if a generator lockout is initiated (exclude alarm)
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1. Trips and blocks closing of generator output breaker BS6-5 and BS2-6 2. Initiates breaker failure protection for BS6-5 and BS2-6. 3. Trips the Main turbine. 4. Trips and blocks closing of the alterex exciter field breaker. 5. If the Main Generator Lockout was due to generator differential overcurrent, the stator cooling water pumps will trip.
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Objective 19
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Identify the six automatic actions which will occur if a unit lockout is initiated (exclude alarm)
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1. 1. Trips and blocks closing of generator output breaker BS6-5 and BS2-6 2. Initiates breaker failure protection for BS6-5 and BS2-6. 3. Trips the Main turbine. 4. Trips and blocks closing of the alterex exciter field breaker. 5. Trips the stator cooling water pumps. 6. Trips cooling fans and pumps for the main power transformers. Lockouts must be locally reset at panel 1AC654 in the upper control equipment room.
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objective 20
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Identify when to use, how to inspect, and how to use electrical gloves and leather protectors
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When to use: How to inspect: Testing with a Test Stick. Operating disconnects, manually operated gang disconnects or grounding switches. Testing for grounds and phasing 600 volts test sets; connecting or disconnecting portable test leads for test sets. Applying or removing portable grounding leads from circuits or equipment.Removing or replacing potential transformer fuses. Removing or replacing bayonet type cut outs or fuses used for station light and power transformers Gloves are inflated before starting the first job of each day on shift. Discard if gloves leak or fail to hold air, any tears or punctures regardless of the size or location, any cuts or abrasions, no matter how minor, which exposes red rubber when stretched.
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objective 12
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Identify when to use, how to inspect, and how to use dielectric boots
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When to use: Required on 13kV and above. How to inspect: Check for cuts, tears or holes.
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objective 12
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Identify when to use, how to inspect, and how to use FAMECA Electronic voltage detector
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When to use: When doing electrical switching on a 500KV bus under the direction of the Electrical Load Dispatcher, you could receive direction to test for potential on the section which was just de-energized. How to use: Screw on hot stick adaptor. Screw on desired electrode (hook). Attach hot stick. Depress "TEST" button, if the diode flashes and if the buzzer beeps, the detector is ready for use when the red lamp stops flashing, the green lamp will light for approximately 2 minutes. The green lamp shows that nothing is wrong with the detector and that there is no voltage on the contact electrode. After acknowledging the test signal, the operator may make contact with the conductor by touching or hanging the electrode on the conductor. BE SURE TO MAKE CONTACT. Use the instrument where you would put the grounding clamps.On a live conductor, the instrument emits audio-visual signals.On dead conductors, no signal is emitted, even in the presence of induced voltage (static). After the potential test has been done on the bus section, verify the operability of the tester by depressing the test pb.
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objective 12
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Summarize the immediate action required by HC.OP-AB.ZZ-0135
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IF the EDG fails to start automatically, THEN START AND LOAD as necessary |
objective 22
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