Electrical Power Engineering Practical Knowledge Questions 1
108, transformer oil is running out what harms it can cause?
A: If the transformer oil is too low it will make light gas moving and severe oil shortages for the cores and windings and these will be exposed to moisture in the air and may cause insulation breakdown.
109, A forced oil circulation transformer can not stop?
A: The reason is that the transformer housing is flat, the cooling area is very small, and even can not transform the transformer no-load loss of heat generated that is scattered out.Therefore, it is dangerous to force the oil circulation transformer to completely stop the operation of the cooling system.
110, If there is gas in the operation of the transformer one should pay attention to what security matters?
A: The safety issues should be noted as:
(1) to take gas it must be carried out by two people, one person from operation and one from guardianship.
(2) if climbing transformer is necessary thenyou should take a safe distance from the gas to prevent high-throw.
(3) to prevent accidental collision probe.
111, what causes the transformer to generate abnormal sound?
A: The following causes the transformer to issue abnormal sound:
(1) overload.
(2) internal contact is bad, discharge spark.
(3) individual parts are loose.
(4) The system is grounded or shorted.
(5) large motor starting to make a big change in load.
112, If a voltage transformer is in operation, why it is not allowed to short-circuit the secondary?
A: The voltage transformer in normal operation, the secondary load impedance is very large, voltage transformer is a constant voltage source, the internal impedance is very small, small capacity, winding wire is very small, when the transformer secondary short circuit, Current is too high, if the secondary has improper fuse,and the fuse is not burned the voltage transformer can easily be burned.
113, what happens when the capacitor immediately exit the operation?
Answer: one of the following conditions happens with immediate exit of capacitor from operation:
(1) casing flashover or serious discharge.
(2) joint overheating or melting.
(3) expansion of shell deformation.
(4) the internal discharge sound and discharge equipment abnormal sound.
114, For arc suppression switching coil tap the operation of what provision?
A: The operating requirements are:
(1) it should be based on duty dispatcher assigned tap position switch for extinction coil tap.
(2) Before changing the tap, make sure that there is no ground fault in the system, and then disconnect the arc suppression coil with the disconnector. After installing the grounding wire, you can switch the tap and measure the DC resistance. Measurement of DC resistance to pass the arc suppression coil can be put into operation.
115, small current grounding system when to apply What are the phenomena?
A: The small current grounding system occurs when the phenomenon of single-phase ground:
(1) alarm ring, while the ground light window, ground signal relay out of licensing.
(2) If the fault point of the high resistance grounded, the ground phase voltage decreases, the other two phase-to-ground voltage is higher than the phase voltage; such as the metal ground, the ground phase voltage dropped to zero, the other two ground voltage rise to line voltage .
(3) three-phase voltmeter pointer non-stop swing.
116, isolating switch in the operation may be abnormal for what causes?
(1) The contact part is overheated.
(2) insulator damage, fracture, wire clamp crack.
(3) pillar insulator gluing Department of poor quality and natural aging caused by insulator cover.
(4) due to serious filthy or over-voltage, flashover, discharge, breakdown grounding.
117, An oil circuit breaker has false trip What are the possible reasons?
A: The oil circuit breaker false tripping reason:
(1) protection malfunction.
(2) Incorrect movement of the circuit breaker mechanism.
(3) secondary circuit insulation problems.
(4) there is a parasitic trip circuit.
118, indication on a circuit breaker red, green light does not light, what it will impact on the operation?
A: Indicator circuit breaker position of the red, green light will run the following hazards.
(1) can not correctly reflect the circuit breaker jump, closing position, failure can easily lead to misjudgment.
(2) If the trip circuit fault, when an accident occurs, the circuit breaker can not trip in time, will expand the accident.
(3) If it is a closed loop fault, circuit breaker accident trip will not automatically overlap or fail .
(4) closing circuit failure can not be the normal operation.
119, Replacement of the red light bulb circuit breaker should pay attention to what matters?
A: Replace the red light bulb circuit breaker should pay attention to:
(1) there must be two people to replace the lamp.
(2) should be replaced with the original lamp the same voltage, power, light bulb.
(3) If you need to remove the lamp, you should use insulating tools to prevent short-circuit or DC ground.
120, the protection of the bus range of protection, including what equipment?
A: bus protection is the protection of the bus section of all the outlet busbar protection between the primary current transformer and the electrical part, that is, all the bus and equipment connected to the bus all the electrical equipment.
121, zero-sequence current protection What are the characteristics?
A: The biggest feature of zero-sequence current protection is:it only response to single-phase ground fault. Because the other non-ground short-circuit faults in the system do not produce zero-sequence current, the zero-sequence current protection is protected against any faults.
122, CSL-216 type microcomputer line protection with what function?
A: With three-phase over-current protection and three-phase reclosing, in addition to both measurement, remote and ground selection line function.
123, visit the power distribution unit into and out of the high pressure room What are the requirements?
A: Check the power distribution device into and out of the high-pressure room, you must lock the door.
124, In a thunderstorms weather outdoor for high voltage equipment, what are the requirements?
A: In a thunderstorm weather, if you need to visit outdoor high-voltage equipment:
(1) should wear insulated boots.
(2) shall not be close to the arrester and lightning rod.
125, the battery daily maintenance?
A: The battery daily maintenance work:
(1) clean the dust, keep the room clean.
(2) timely maintenance failure of the aging battery.
(3)Eliminate the leakage of electrolyte.
(4) Periodically apply Vaseline to connection terminals.
(5) Regularly charge and discharge the battery.
(6) filling the electrolyte, pay attention to specific gravity, liquid level, liquid temperature.
(7) Write down the operating status of the battery
