In these large cities in the east and south, electricity consumption is high and the local electricity supply is far from sufficient. Therefore, electricity can only be transmitted from west to east and from north to east. south. Therefore, the east-west extent and the north-south extent are large and the distance is too far. The standard voltage 220V/380V electricity used to send to these cities cannot be used by users and industries once it arrives at its destination. The long-distance transmission process will be greatly affected by losses, so the only way to solve long-distance power transmission is to increase the voltage. Since high voltage power transmission increases the voltage and then sends it to the destination, this means that no electricity is needed during the journey to the destination.
Whether it is a thermal power plantEU or a hydroelectric plant, the electricity produced is three-phase, three-wire electricity. For long distance transportation, the voltage must be increased via a booster station, with the. the purpose of transporting electricity to the destination. In this process, domestic electricity and industrial electricity are not taken into account, so there is no need to use a neutral line. On the surface it is about saving materials, but in reality it is about reducing costs as much as possible.
Once the high voltage electricity reaches its destination, a step-down transformer is needed to reduce the voltage. At this point, not only civil and industrial electricity must be taken into account, but also electrical safety. Since the neutral line and ground wire are only considered in the 380V/220V low-voltage distribution network, the general power supply methodselectrical in the low voltage distribution network include a three-phase four-wire system and a three-phase five-wire system. Therefore, a line is drawn from the neutral point of the secondary side star connection of the step-down transformer in the low voltage distribution network, i.e. the neutral line. At present, the neutral line and one phase of the three-phase power supply have a phase voltage of 220V, and the line voltage of the two lines of the three-phase power supply is 380V. It can be used not only for civil use, but also. also for industrial use.
The three- and four-wire power supply method has only one neutral wire and no ground wire, which can prevent the neutral wire from being electrified due to three unbalanced phases. The three-phase five-wire power supply method has a neutral wire and a ground wire. The ground wire at this time can guarantee the reliability of the electricctricity of the user. However, the neutral wire and the ground wire must be wired repeatedly to prevent the neutral wire from being open circuited and causing the neutral wire to be electrified and accidentally injure people.
Excuse me, is there only one neutral wire and one live wire in the transmission process between the electricity from the power plant and the users?
I think I can understand it according to your idea
It is true that the electricity produced by the generator does not need to be connected to the electricity grid, and it does not There is no need to distinguish between neutral and live wires
Additionally, if the output end of the generator is not grounded, there will be no distinction between the neutral wire and the wire under tension. This 220 V can be considered as the line voltage. .
But it may be a habit developed by old electricians. I have the printession that I should respect them and pretend to be cool.
Just to have fun with this, take an extra electric test pen and click on it a few times. This other person can feel comfortable and your work can be done smoothly. Obviously this person's technical affairs are very bad, so there is no need to compete with him. and it will offend everyone. Why bother?
Hello, I'm happy to answer your questions! The lines coming out of the power plant are usually high voltage lines. The aim is to reduce own energy transmission losses over long distances. These high voltage lines are generally three-phase, four-wire structures (three live wires and one). neutral wire).Once entering the house, the transformer switches to low voltage 220V. The bottom hole of the three-hole plug is the ground connection. The lineThe high voltage must have at least three live wires (to transmit current) and one neutral wire (to form a loop, form a circuit and be connected to the machine shell to protect people from electric shock in areas where high density). In the event of lightning, lightning protection wires can be added (to protect residents of the circuit from burnouts caused by the high instantaneous current caused by lightning).
In the house, the two-hole outlet has a live wire (marked L on the outlet to pass current) and a neutral wire (marked N to form a loop). These two wires are angled outward (including live and neutral wires), and the other is the ground wire (for grounding, for personal safety).
Do you understand now?