The semi-insulation of the loader is the main insulation of the windings of the transformer's near-neutral part, and its insulation level is lower than that of the end windings. On the contrary, the general insulation level of the first and tail windings of the transformer is the same as full insulation .
1. What is the primary effect of the transformer in the power system?
The effect of the power system in the transformer is to transform the voltage to facilitate the transmission of power. After the voltage is boosted by the step-up transformer, it can reduce line losses, improve the economics of power transmission, and achieve the purpose of long-distance power transmission. The step-down transformer can turn the high voltage into the application voltage required by the user to meet the user's needs.
2. What are the main components of oil-immersed transformers?
The main components of the transformer are: iron core, winding, oil tank, oil pillow, respirator, explosion-proof tube, radiator, insulating sleeve, tap changer, gas relay, thermometer, clean oil, etc.
3. What is a fully insulated transformer? What is a semi-insulated transformer?
4. What are the wiring methods for current transformers?
Current transformer wiring methods include two-phase V-shaped wiring and two-phase current differential wiring using two current transformers; three-phase Y-shaped wiring, three-phase delta wiring and zero-sequence wiring using three current transformers.
5. How many kinds of reactive power sources in the power system?
Reactive power sources in the power system are: ① synchronous generator; ② camera adjustment; ③ parallel compensation capacitor; ④ series compensation capacitor; ⑤ static compensator.
6. What is the harm of casing cracks?
Cracks in the bushing will reduce the insulation strength, which can cause further damage to the insulation until all breakdown. The water in the cracks may also burst the casing when it freezes. It can be seen that the cracks in the bushing are very threatening to the safe operation of the transformer.
7. What effect does the high-voltage circuit breaker have?
The high-voltage circuit breaker can not only block and connect the no-load current and load current in the high-voltage circuit under normal conditions, but also cooperate with maintenance equipment and automatic equipment when the system fails, quickly block the fault current, avoid the expansion of the accident, and ensure the system. Safe operation.
8. What effect does the wave blocker have?
The wave blocker is an indispensable high-frequency communication component for carrier communication and high-frequency maintenance. It prevents high-frequency current from leaking to other branches and reduces the high-frequency energy loss.
9. What effect does the current transformer have?
Current transformer turns large current into small current according to certain proportion, supplies current for various instrument applications and relay maintenance, and isolates secondary system from 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.
10. Why is there electricity in a short period of time after the cable line is powered off and is tested with a test pen?
The cable circuit is equivalent to a capacitor. After the power failure, the line still has residual charge, and there is still a potential difference to ground. If the power is checked immediately, the electroscope will show that there is power on the line. Therefore, it is necessary to fully discharge, and no electricity after inspection, before installing the ground wire. 1515. What is internal overvoltage?
The DC system supplies reliable DC power for control, signal, relay maintenance, automatic equipment and incident lighting in the substation. It also provides reliable operating power for operation. The availability of the DC system plays a crucial role in the safe operation of the substation, and is the guarantee of the safe operation of the substation.
11. What effect does the central signal equipment have?
The central signal is a signal device that supervises the operation of electrical equipment in substations. It emits sound and light signals according to the fault characteristics of electrical equipment, and advises the operating personnel to quickly find, make correct judgments and processing, and ensure the safe operation of equipment.
12. In order to keep the battery fully charged during normal floating charging, what should the terminal voltage of each battery be?
In order to keep the battery in a fully charged state, it is necessary to keep each battery connected to the DC bus at a voltage of 2.15V during floating charging.
13. Why install DC insulation supervision equipment?
Substation direct current system is not allowed to work for a long time because the grounding of another pole at another location on the same pole may cause malfunction of signal equipment, relay maintenance and control circuits. In addition, when one pole is grounded, it is assumed that another pole will be grounded to form a DC short circuit.
14. The internal overvoltage is due to operation, accident or other reasons. The sudden change of the system status will cause a transition process from one stable state to another stable state. 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 they are called internal overvoltages.
15, 220kV valve type surge arrester upper pressure ring what effect?
After installing the equalizing ring, the voltage of the arrester will be evenly distributed.
What is maintenance zero connection? What are the advantages?
Maintenance zero connection is a method of directly connecting the metal parts of the equipment that are not charged under normal conditions with wires to the system. Adopting the maintenance zero-connection method to ensure personal safety and avoid electric shock accidents.
16. What is the difference between neutral point and zero point and zero line?
The common connection point where the first end (or tail end) of the three-phase winding is connected together is called the power supply neutral point. When the neutral point of the power supply has a good connection with the grounding device, the neutral point is called the zero point; and the wire drawn from the zero point is called the zero line.
