Power distribution operation test questions (volume B) - Solutions - Huaqiang Electronic Network

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First, the True/False questions:
1. It is strictly prohibited for staff to move or remove the fence, grounding wire, and signboard during work. ( )
2. It is not allowed to directly pull the arrester with the isolating switch during rain or snow. ( )
3. In an emergency, the duty officer has the right to handle the situation first when rescuing an electric shock victim, extinguishing a fire, or saving critical equipment, then report to the dispatcher. ( )
4. In a 6-10kV ungrounded system, when a single-phase ground fault occurs, the phase voltage of the non-fault phase will decrease simultaneously. ( )
5. The impact closing test on a newly commissioned transformer is performed to check if the main circuit breaker on each side can withstand operating overvoltage. ( )
6. Before measuring insulation resistance, the device under test must be discharged to ground, and no one should touch it during the measurement. ( )
7. When power is off for maintenance, the operating power from the open circuit breaker and disconnector should be removed, and the isolating switch operation handle must be locked. ( )
8. The transformer oil level gauge is used to indicate the oil level in the oil pillow. ( )
9. During a switching operation, personnel can be changed in case of special circumstances. ( )
10. An isolating switch can directly operate a 110kV or 10kV no-load line. ( )
11. The magnetic field of the induced current is always opposite to the original magnetic field. ( )
12. The fluctuation range of the DC bus voltage should not exceed ±5%. ( )
13. The current transformer isolates high voltage from secondary equipment such as instruments and protection devices, ensuring the safety of personnel and equipment. ( )
14. The operating sequence for horizontally or triangularly arranged high-voltage fuses is: first the two sides, then the middle. ( )
15. Internal overvoltage includes operating overvoltage, resonant overvoltage, and power frequency overvoltage. ( )
Second, multiple-choice questions:
1. In a DC circuit, inductance is equivalent to ( ).
A. Open circuit
B. Short circuit
C. Open circuit
D. Not present
2. The operation items on the operation ticket must include the check item, which should be filled with a double name, i.e., the device's ( ).
A. Location and number
B. Name and location
C. Name and meter
D. Name and number
3. The temperature of the battery room is generally required to remain in ( ).
A. 5~8°C or less
B. Not exceeding 20°C
C. 10~30°C
4. If the isolating switch is misoperated, the handling method should be ( ).
A. Immediately open
B. Immediately close
C. Do not open again; close after arc is broken
5. The vent of the SF6 distribution room should be located at ( ).
A. Bottom of the room
B. Top of the room
C. Center of the room
6. When the transformer nameplate indicates rated voltage Ue±2*2.5%, the transformer ( ).
A. Three-stage voltage regulation
B. Five-stage voltage regulation
C. On-load voltage regulation
7. When a short-circuit fault occurs in the power system, the voltage usually ( ).
A. Rises sharply
B. Drops sharply
C. Becomes more stable
D. Remains unchanged
8. The transformer’s neutral point is grounded, so the transformer casing ( ).
A. Must still be grounded
B. No longer needs to be grounded
C. Depends on the grounding location
9. When oiling the transformer, the oil level should be raised to the position corresponding to ( ).
A. Ambient temperature
B. Oil temperature
C. Winding temperature
10. The scope of the transformer differential protection covers ( ).
A. Low-voltage side of the transformer
B. Medium-voltage side of the transformer
C. Equipment between current transformers on both sides of the transformer
11. If gas is found in the transformer gas relay ( ).
A. Indicates a fault inside
B. Not necessarily a fault
C. Indicates a major fault
D. No fault
12. Before inputting the transformer differential protection, ( ) should be measured for phase and voltage.
A. No load
B. With load
C. Not necessarily
D. Slight load
13. For electrical workers in a 10kV distribution room, the minimum safe distance between the normal working area and live equipment is ( ).
A. 0.35m
B. 0.40m
C. 0.50m
14. To reduce the recovery voltage rise speed between circuit breaker contacts and prevent oscillating overvoltage, a ( ) may be installed between the contacts.
A. Voltage equalizing capacitor
B. Series capacitor
C. Voltage equalizing belt
15. If one phase of the low-voltage side of the potential transformer has zero voltage, and the other two phases remain unchanged, while the line voltage decreases by two, this indicates ( ).
A. Two-phase fuse break on the low-voltage side
B. One-phase lead break on the low-voltage side
C. One-phase lead break on the high-voltage side
D. Two-phase lead break on the high-voltage side
Third, fill in the blanks:
1. The power safety work regulations stipulate that the organizational measures to ensure safety include the _________ system, the work permit system, the __________ system, and the __________ system.
2. When operating a switch, the guardian must __________, and the operator must __________, and the check is correct. After the guardian gives the order, the operator can proceed.
3. When checking for electricity, use a voltage-level electroscope to check the power on each side of the access line of the maintenance equipment. Before testing, test it on __________ to confirm the electroscope is working.
4. The maintenance equipment and the circuit breaker (switch) and disconnector (knife switch) on the incoming side should be disconnected from __________ and __________, and the isolating switch (knife gate) operation handle should be locked to prevent accidental power supply.
5. Personnel who have been approved by company leaders to independently inspect high-voltage equipment must not perform any other work while patrolling, and must not be blocked by __________ or __________.
6. The operational status of substation equipment is divided into four states: operation, __________, __________, and __________.
7. The structure of the isolating switch is characterized by __________, and no __________, therefore, it cannot cut or close __________ circuits.
8. The input of a no-load transformer will produce __________.
9. For fire fighting of live equipment, dry powder fire extinguishers and carbon dioxide fire extinguishers should be used. __________ should not be used for fire fighting.
10. The secondary side of the transformer must be __________ to ensure the safety of personnel and equipment.
Fourth, calculation problem:
A three-phase SZL—31500/38.5KV transformer has a rated capacity of 31500KVA, with a primary rated voltage of 110KV and a secondary rated voltage of 38.5KV. Calculate the primary and secondary rated currents of the transformer.