The significance of reactive power compensation

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Categories:company news
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Time of issue:2022-05-17
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(Summary description)Why do we need reactive power compensation? From the function of reactive power, it can be seen that the electrical equipment should not only obtain active power from the power supply, but also obtain reactive power from the power supply. If the reactive power in the power grid is too low, the electrical equipment will not have enough reactive power to establish a normal electromagnetic field, these electrical equipment will not be able to work under rated conditions, and the terminal voltage of the electrical equipment will drop, which will affect the normal operation of the electrical equipment.

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The significance of reactive power compensation

Top

(Summary description)Why do we need reactive power compensation? From the function of reactive power, it can be seen that the electrical equipment should not only obtain active power from the power supply, but also obtain reactive power from the power supply. If the reactive power in the power grid is too low, the electrical equipment will not have enough reactive power to establish a normal electromagnetic field, these electrical equipment will not be able to work under rated conditions, and the terminal voltage of the electrical equipment will drop, which will affect the normal operation of the electrical equipment.

Categories:company news
Author:
Origin:
Time of issue:2022-05-17 13:53
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1、 Why do we need reactive power compensation?

From the function of reactive power, it can be seen that the electrical equipment should not only obtain active power from the power supply, but also obtain reactive power from the power supply. If the reactive power in the power grid is too low, the electrical equipment will not have enough reactive power to establish a normal electromagnetic field, these electrical equipment will not be able to work under rated conditions, and the terminal voltage of the electrical equipment will drop, which will affect the normal operation of the electrical equipment.
When the reactive power supplied in the power grid line is far from meeting the needs of the load, we need to set up some reactive power compensation devices to supplement the reactive power, so as to ensure the needs of users for reactive power, so that the electrical equipment can work under the rated voltage. This is what we call reactive power compensation. Reasonable selection of compensation device can minimize the loss of network and improve the quality of power grid. Improper use of the power supply system may cause many factors such as voltage fluctuation or harmonic increase.

2、 Principle of reactive power compensation

The output power of power grid includes two parts: one is active power; The second is reactive power. Directly consume electric energy, convert electric energy into mechanical energy, thermal energy, chemical energy or sound energy, and use these energy to do work. This part of power is called active power; It does not consume electric energy, but only converts electric energy into another form of energy. This energy is a necessary condition for electrical equipment to work, and this energy is periodically converted with electric energy in the power grid. This part of power is called reactive power, such as the electric energy occupied by electromagnetic components to establish magnetic field and electric energy occupied by capacitors to establish electric field. When the current works in the inductive element, the current is 90 degrees ahead of the voltage. When the current works in the capacitive element, the current lags behind the voltage by 90 degrees. In the same circuit, the direction of inductive current and capacitive current is opposite, with a difference of 180 degrees. If the capacitive elements are installed in the electromagnetic element circuit in proportion, so that the currents of the two offset each other and reduce the included angle between the current vector and the voltage vector, so as to improve the ability of electric energy to do work, this is the principle of reactive power compensation.

3、 Reactive power compensation mode

1)Centralized compensation: it is installed on the 6 ~ 35kV bus of the enterprise or local general substation, which can reduce the reactive power loss of the high-voltage line and improve the power supply voltage quality of the substation.
2) Decentralized compensation: installed on the high-voltage or low-voltage bus of workshop or village terminal substation and distribution substation with low power factor. This method has the same advantages as centralized compensation, but the reactive capacity is small and the effect is obvious.
3)Local compensation: it is installed near asynchronous motor or inductive electrical equipment for local compensation. This method can not only improve the power factor of the power supply circuit of electric equipment, but also change the voltage quality of electric equipment.

4、 Function of reactive power compensation

The main function of reactive power compensation is to improve power factor to reduce equipment capacity and power loss, stabilize voltage and improve power quality, improve transmission stability and transmission capacity in long-distance transmission, and balance the active and reactive power of three-phase load.
Reactive power compensation can receive the following benefits:
1) According to the power factor of electric equipment, the power loss of transmission line can be calculated. Through on-site technical transformation, the power factor lower than the standard requirements can meet the standard and realize the purpose of power saving.
2) Using reactive power compensation technology to improve the power factor of low-voltage power grid and electrical equipment has become an important measure of power saving.
3) Reactive power compensation is to provide necessary reactive power with the help of reactive power compensation equipment, so as to improve the power factor of the system, reduce energy consumption, improve the voltage quality of the power grid and stabilize the operation of the equipment.
4) Reduce power loss. Generally, the power loss of factory power wiring is about 2% - 3% according to different lines and loads. After using capacitors to improve the power factor, the total current is reduced, which can reduce the power loss at the power supply end and the power consumption end.
5) Improve the power supply quality, improve the power factor, and reduce the total load current and voltage drop. Adding a capacitor to the secondary side of the transformer can improve the power factor and increase the secondary side voltage.
6) Extend equipment life. After improving the power factor, the total current of the line is reduced, which reduces the capacity load of machines and equipment such as transformers, switches and lines that are close to or have been saturated. Therefore, the temperature rise can be reduced and the service life can be increased (the service life can be doubled for every 10 ° C reduction in temperature)
7)Finally, it can meet the monitoring requirements of reactive power compensation in power system and eliminate the penalty caused by too low power factor.
8)Reactive power compensation can improve power quality, reduce power loss, tap the potential of power generation and supply equipment, and reactive power compensation can reduce users' electricity expenditure. It is an energy-saving measure with less investment and quick effect.
9)The influence of reactive power compensation technology on the low-voltage distribution network of power users and the economic and social benefits brought by improving the power factor, determine the compensation capacity of reactive power, ensure that the compensation technology is economic, reasonable, safe and reliable, and achieve the purpose of saving electric energy.