Electrician compulsory courses, learning electromechanical integration and electrical automation are all to see - Solutions - Huaqiang

Probe current voltage pin 420*4450 head diameter 5.0 over current current and voltage pin

TP-IP4220CZ6 5V 0.35PF breakdown voltage 6V SOT

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Photocoupler

Electrician compulsory course
1. What are the main components of the oil-immersed transformer?
Answer: The main components of the transformer are: iron core, winding, fuel tank, oil pillow, respirator, explosion-proof tube, radiator, insulating sleeve, tap changer, gas relay, thermometer, net oil, etc.
2. What is a fully insulated transformer? What is a semi-insulated transformer?
Answer: Semi-insulation is the main insulation of the near-neutral part of the transformer. The insulation level is lower than the insulation level of the end winding. On the contrary, the insulation level of the first end and the end winding of the transformer is called full insulation.
3. What is the main role of the transformer in the power system? A: The role of the transformer in the power system is to change the voltage to facilitate the transmission of power. After the voltage is boosted by the step-up transformer, the line loss can be reduced, the economy of power transmission can be improved, and the purpose of long-distance power transmission can be achieved. The step-down transformer can turn the high voltage into the voltage used by the user at all levels to meet the needs of the user.
4. What is the danger of casing cracking?
A: Cracks in the casing will reduce the insulation strength and cause further damage to the insulation until all breakdown. It is also possible for the casing to burst when the water in the crack freezes. It can be seen that the casing crack is very threatening to the safe operation of the transformer.
5. What is the role of the high voltage circuit breaker?
Answer: The high-voltage circuit breaker can not only cut off and turn on the no-load current and load current in the high-voltage circuit under normal conditions, but also cooperate with the protection device and the automatic device in the event of a system failure to quickly cut off the fault current and prevent the accident from expanding. Ensure the safe operation of the system.
6. What is the role of the wave blocker?
Answer: The wave blocker is an indispensable high-frequency communication component for carrier communication and high-frequency protection. It prevents high-frequency current from leaking to other branches and reduces the loss of high-frequency energy.
7. What is the role of current transformers?
Answer: The current transformer converts the large current into a small current according to a certain ratio, providing various currents for instrument use and relay protection, and isolating the secondary system from the high voltage. It not only ensures the safety of people and equipment, but also simplifies and standardizes the manufacture of instruments and relays, and improves economic efficiency.
8. What kinds of wiring methods are there for current transformers?
Answer: The current transformer is connected by two-phase V-line and two-phase current difference wiring with two current transformers; three-phase Y-connection, three-phase delta connection and zero sequence using three current transformers wiring.
9. How many reactive power sources are there in the power system?
Answer: The reactive power supply in the power system is: 1 synchronous generator; 2 adjustable camera; 3 parallel compensation capacitor; 4 series compensation capacitor; 5 static compensator.
10. Why should a set of ZnO arresters be installed between the power capacitor and its circuit breaker?
Answer: The installation of ZnO arrester can prevent the operating overvoltage of power capacitors during pull-and-close operation and ensure the safe operation of electrical equipment.
11. What are the differences between the values ​​indicated by the energy meter and the power meter?
Answer: The power meter indicates the number of electrical functions that are sent, transmitted, and consumed by the instantaneous transmitting, supplying, and powering equipment. The value of the energy meter is the cumulative amount of energy that is sent, transmitted, and consumed during a certain period of time.
12. What are the requirements for the battery of the parallel battery pack?
Answer: The electromotive force of each battery in the parallel battery should be equal. Otherwise, the battery with large electromotive force will discharge the battery with small electromotive force and form a circulation inside the battery pack. In addition, the internal resistance of each battery should also be the same, otherwise the discharge current of the battery with small internal resistance will be too large. Batteries with different old and new levels should not be used in parallel.
13. What is the role of the central signal device?
Answer: The central signal is a kind of signal device for monitoring the operation of substation electrical equipment. It emits sound and light signals according to the fault characteristics of electrical equipment, and informs the operation personnel to quickly find and make correct judgment and treatment to ensure the safe operation of the equipment.
14. Why is there still electricity in a short time when the cable line is powered off with an electroscope?
A cable line is equivalent to a capacitor. After the power failure, the line still has residual charge, and there is still a potential difference to the ground. If the power is turned off immediately, the electroscope will show that there is power on the line. Therefore, it must be fully discharged, and the grounding wire can be installed after the power is checked.
15. What is internal overvoltage?
Answer: The internal overvoltage is a transition from a stable state to another stable state due to sudden changes in the state of the system due to operation, accident or other reasons. In this process, there may be dangerous overvoltages to the system. . These overvoltages are caused by the oscillation and accumulation of electromagnetic energy in the system, so it is called internal overvoltage.
16. What is the role of the upper pressure equalizing ring of the 220kV valve type arrester?
Answer: After installing the equalizing ring, the voltage distribution of the arrester is even.
17. What is protection and zero? What are the advantages?
Answer: Protecting the zero is the way in which the metal part of the device is not charged under normal conditions, and the wire is directly connected to the system. Take the protection and zero connection method to ensure personal safety and prevent electric shock accidents.
18. What is the difference between neutral point and zero point and zero line?
Answer: The common connection point where the first end (or the tail end) of the three-phase winding is connected together is called the neutral point of the power supply. When the neutral point of the power supply is well connected to the grounding device, the neutral point is called zero point; and the wire drawn from the zero point is called the zero line.
19. What role does the DC system play in the substation?
Answer: The DC system provides a DC power supply for control, signal, relay protection, automatic devices and accident lighting in the substation. It also provides operational power for operation. The availability of the DC system plays a vital role in the safe operation of the substation and is the guarantee for the safe operation of the substation.
20. In order to keep the battery fully charged during normal float charging, what should the terminal voltage of each battery be kept?
A: In order to keep the battery in full charge, each battery connected to the DC bus must be kept at 2.15V when floating.