Three-phase alternating current is a form of transmission of electrical energy, referred to as three-phase electricity. The three-phase AC power supply is a power supply composed of three alternating current potentials of the same frequency, equal amplitude, and phase difference of 120°.
Industrial power generally uses three-phase power, but we use single-phase power in our daily life. The three-hole socket is actually single-phase power, one fire line, one zero line, and one ground.
Therefore, some small partners call a single-phase three-hole socket with a grounding hole as three-phase power, which is wrong. In order to avoid other misunderstandings about three-phase power, the following is a brief introduction to introduce three-phase power.
Three-phase power generation principle
Power generation in power plants generally converts large energy electromagnets into sinusoidal alternating currents by converting natural energy such as water, firepower, and wind power into kinetic energy. In order to maximize power generation efficiency, three coils are generally installed in the generator.
Because through practical application and combined with the cost of the generator, it is found that the use of three coils is the most stable and economical solution. The three coils in the generator are distributed at an angle of 120 degrees, so that the generator output has three phases. They are called A, B, and C phases, respectively.
Figure 1 Principle of three-phase power generation
Three-phase power transmission
After outputting three-phase electricity from the power plant, the AC power is first boosted to hundreds of thousands of volts by a step-up transformer and then transported to a remote location, and then the high voltage is reduced to a low voltage for civilian use (220V) or industrial use by a step-down transformer ( Three-phase 380V).
On the transmission tower, many high-voltage transmission lines can often be seen. If you look closely, you can find that there are two thin lines at the top of the tower. This is not for power transmission, but for lightning protection, also called ground.
Below the lightning protection line is the transmission line. The number of roots is a multiple of 3. These three lines are the fire lines we often say. They are connected to the three-phase power supply line of the power station, which is the three-phase output of the alternator mentioned above. Electricity.
Figure 2 Three-phase electrical transmission
Three-phase power application and wiring
Three-phase power is mainly used in the industrial field to supply power to loads that need to be connected to a three-phase power supply to operate normally.
In fact, the distinction between three-phase equipment and single-phase equipment is very obvious, as shown in the following figure.
Figure 3 Schematic diagram of wiring separation between three-phase equipment and single-phase equipment
Three-phase electricity common problem: imbalance
In the process of using three-phase electricity, the ideal three-phase power should be a perfect sine wave, but some factors will make the waveform deviate from the sine, thus causing power quality problems, such as three-phase unbalance.
The three-phase unbalance is caused by the uneven load of each road. The main hazard is to increase the power loss of the line and distribution transformer, affect the safe operation of the power equipment, and reduce the efficiency of the motor.
If the three-phase load is unbalanced, the power supply efficiency of the line and the distribution transformer will be reduced. If the heavy load is overloaded too much, the phase conductor may be blown, the switch may be burnt out, or even the single phase of the distribution transformer may be burned.
Figure 4 Accident scene caused by three-phase unbalance
The main advantages of three-phase electricity
Three-phase power can be popularized, which has a lot to do with its own advantages.
First, in terms of power generation, the three-phase alternator has a larger capacity than the single-phase alternator of the same size;
Second, in terms of power transmission, if the same voltage is delivered to the same distance by the same voltage, the three-phase transmission line saves material compared to the single-phase transmission line;
Thirdly, in terms of electrical equipment, the three-phase AC motor is simpler in structure, smaller in size and better in operating characteristics than the single-phase motor. Therefore, the three-phase system is the main power supply method in various countries. The three-phase electric wire voltage in China is 380V.
Outdoor LED garden spike luminaire is available in several colour variants and comes equipped with a powerful, warm-white 6 Watt LED. The luminaire is made of die-casting aluminium and is connected using the supply cable incl. 24V low voltage high safety use. IP65 waterproof with longlife span.
Our other products range:Led underground Light, LED Underwater Light , LED Wall Washer Light, LED Linear Light , LED Outdoor Flood Light, LED Garden Light , LED Landscape Light , LED Strip Light , LED Step Light etc.
Courtyard light.Spike Light,Garden Light.Light in Garden.
SHENGYA LIGHTING TECHNOLOGY CO., LTD. , https://www.syalighting.com