Basic knowledge of electrician

Classification：Company   2018-05-02 21:07:21

1. What are the main components of an oil immersed transformer? 　　

Answer: the main components of the transformer are iron core, winding, oil tank, oil pillow, ventilator, explosion proof tube, radiator, insulating sleeve, split switch, gas relay, thermometer, net oil and so on.

2. What is a fully insulated transformer? What is a semi insulated transformer?　　

Answer: half insulation is the main insulation of the near neutral part of the transformer, whose insulation level is lower than that of the end winding. In contrast, the first end of the transformer is the same as the insulation level of the tail end winding.

3. What are the main functions of transformers in the power system?　　

Answer: the role of transformer in power system is to transform voltage to facilitate power transmission. After the voltage is boosted by the step-up transformer, the line loss can be reduced, the economy of power transmission can be increased, and the purpose of long-distance power transmission can be achieved. The step-down transformer can turn the high voltage to all levels of voltage needed by users to meet the needs of users.

4. What is the harmfulness of the casing crack? 　　

Answer: Cracks in the casing will reduce the insulation strength and cause further damage to the insulation until all the breakdown occurs. When the water in the crack freezes, it may crack the casing. It is evident that the casing crack is a threat to the safe operation of the transformer.

5. What is the function of high voltage circuit breaker? 　　

Answer: the high voltage circuit breaker not only can cut off and connect the no-load current and load current in the normal high voltage circuit, but also can cooperate with the protection device and automatic device in the case of the failure of the system, quickly cut off the fault current, prevent the accident from expanding, and ensure the safe operation of the system.

6. What is the function of the wave hindrer?

Answer: the impedance wave device is an indispensable high frequency communication element for carrier communication and high frequency protection. It prevents high frequency current from leaking to other branches and reduces the role of high frequency energy loss.

7. What is the function of the current transformer? 　　

Answer: the current transformer changes the large current to a small current in a certain proportion and provides the current for the use of various instruments and relay protection, and the two system is isolated from the high voltage. It not only guarantees the safety of the body and equipment, but also simplification and standardization for the manufacture of meters and relays, and improves the economic benefits.

8. What are the wiring ways of the current transformer?　　

Answer: the connection mode of current transformer has two two phase V connection of current transformer and two phase current difference connection; there are three phase Y connection, three phase &Delta, form connection and zero sequence connection using three current transformer.

9. There are several kinds of reactive power sources in the power system. 　　

Answer: the reactive power sources in the power system include: (1) synchronous generator; (2) adjustable camera; (3) shunt compensation capacitor; (4) series compensation capacitor; (5) static compensator.

10. Why do we install a group of ZnO arresters between power capacitors and their circuit breakers? 　　

Answer: the installation of ZnO arrester can prevent the operation overvoltage of power capacitor when it is pulled and operated, so as to ensure the safe operation of electrical equipment.