When do you need to improve the power factor?

Electricity enterprises should reasonably choose power and equipment, and make full use of naturePower factorWhen the natural power factor fails to meet the assessment requirements, it is necessary to add capacitor input compensation to improve the power factor.

The power factor is the ratio of active power to apparent power. When the power factor is low, it will occupy the output capacity of generators, transformers, lines, etc., so that their voltage loss will increase, and the power supply voltage quality will be reduced.

A typical switching power supply starts with a rectifier diode.

A DC voltage is generated, and the output voltage is generated from the DC voltage. Due to the rectifier.

It is a nonlinear element, and its input current will have many higher-order harmonic components.

Power factorSince the proportion of active power in the total power is indicated, it is clear that the power factor cannot be greater than 1 under any circumstances. As can be seen from the power triangle, when = 0°, i.e., the voltage and current in the AC circuit are in phase, the active power is equal to the apparent power.

At this time, the value of cos is the largest, that is, cos=1, when there is only a pure resistive load in the circuit, or the inductive and capacitive reactances in the circuit.

This is the case when they are equal.

The above content reference: Encyclopedia - Power Factor.

In the factory, due to the use of a large number of motors as a drag device, and the motor is an inductive circuit, it is bound to produce a large amount of reactive power on the power grid, thus polluting the power grid, the power plant is not allowed to such a thing to happen often, so you must be equipped with a capacitor to improve the power factor.

A typical switching power supply first uses a rectifier diode to generate a DC voltage, which then generates an output voltage from the DC voltage. Since the rectifier is a nonlinear element, its input current will have many higher harmonic components.

This situation is a problem for power companies, because it is not possible to compensate for the harmonic components of high frequencies by adding capacitors and inductors. Therefore, some regions have begun to legislate that all power supplies with power greater than a certain value need to have a power factor correction function.

The first is; The equipment needs reactive power, the wire diameter is relatively thin, the power supply distance is relatively long, and the voltage drop is relatively large.

Generally speaking, all installed inductive electrical equipment should improve the power factor.

Increasing the power factor can improve the utilization rate of the equipment.

Increasing the power factor can reduce line losses.

Increasing the power factor improves the quality of power supply.

Improving the power factor can reduce the company's electricity bill.

In AC circuits, the cosine of the phase difference ( ) between voltage and current is called the power factor, which is denoted by the symbol cos. Numerically, the power factor is the ratio of the active power to the apparent power, i.e., cos = p s. The magnitude of the power factor is related to the load nature of the circuit, such as the power factor of the resistance load of incandescent bulbs and resistance furnaces is 1, and the power factor of the circuit with inductive load is generally less than 1.

By improving the power factor, the total current in the line and the capacity of electrical components in the power supply system, such as transformers, electrical equipment, wires, etc., are reduced, so not only the investment cost is reduced, but also the loss of its own electric energy is reduced.

By ensuring a good power factor, the voltage loss in the power supply system can be reduced, the load voltage can be more stable, and the quality of power can be improved.

It can increase the margin of the system and tap the potential of power generation and power supply equipment. If the power factor of the system is low, the power factor can be increased and the capacity of the load can be increased by installing capacitors while the capacity of the existing equipment remains unchanged.

Reduced electricity bills for users; Electricity tariff concessions through the reduction of the loss of the above components and the increase of the power factor.

Measures to improve the power factor:

1. Improve the natural power factor of the equipment itself, which is mainly to avoid the situation of large horse-drawn trolleys when choosing electrical equipment;

2. It is to use reactive power compensation devices such as capacitance compensation cabinets to improve the power factor of the system.

The significance of improving the power factor: (1) Improving the quality of electricity and improving the operating conditions of the equipment can ensure that the equipment works under normal conditions, which is conducive to safe production. (2) It can save electricity, reduce production costs, and reduce the electricity expenses of enterprises.

3) It can improve the utilization rate of the enterprise's electrical equipment and give full play to the potential of the enterprise's equipment. (4) It can reduce the power loss of the line and improve the transmission efficiency of the power grid. (5) Due to the limitation of the power generation capacity of the generator, the increase of the power factor also enables the generator to produce more active power.

The power generation equipment can send less reactive load and more active load, and at the same time, it can also reduce the loss on the power generation and power supply equipment and save electric energy.

The purpose of improving the power factor is to reduce the reactive power and improve the utilization rate of the power supply.

Improving the power factor is one of the basic requirements of the power system, the power factor is lower than a certain value to be punished, and a certain reward is given when the increase is more, the purpose is as follows: the first is to ensure that the proportion of reactive power in the power system can not be too much, otherwise the use of the power user is too reactive, which will reduce the quality of power supply.

Secondly, the reactive power is insufficient, which increases the line loss, so the user is required to compensate the reactive power in the gear state and add capacitors and other measures to the source.

Ways to improve the natural factor:

1) Properly select the motor capacity, reduce the reactive power consumption of the motor, and prevent the "big horse-drawn trolley".

2) For light-duty motors with an average load of less than about 40% of their rated capacity, the coil can be changed to a triangle connection (or automatic conversion).

3) Avoid no-load operation of motors or equipment.

4) Configure the transformer reasonably and select its capacity appropriately.

5) Adjust the production shift, balance the electricity load, and improve the electricity load rate.

6) Improve the layout of distribution lines to avoid twists and turns.

In practice, circuit capacitors or condensers can be used, and power capacitors are generally used to compensate for reactive power, that is, parallel capacitors on inductive loads. Here's a theoretical explanation:

The method of paralleling the coarse container of the electric car on the inductive load can compensate the reactive power of the inductive load with the reactive power of the capacitor, so as to reduce or even eliminate the original energy exchange between the inductive load and the power supply.

The significance of improving the power factor is that under the condition that the total power is constant, the larger the power factor, the greater the active power supplied by the power supply. In this way, by improving the power factor, Tan Jing can make full use of transmission and power generation equipment.

In an AC circuit, the ratio of active power to apparent power. That is, with vertical prudence p s=cos, it is called the power factor. Increasing the power factor can reduce the reactive power flow and achieve reactive power in-situ balance.

The reactive power does not flow, so the line loss is reduced, so that the ability of a cable of the same thickness to transmit electricity is improved.

Measures to improve the power factor:

1. Improve the natural power factor.

Improving the natural power factor refers to improving the power factor of the enterprise without using any reactive power compensation device.

When choosing an electric motor, you should choose an energy-efficient motor and do not use a motor with high energy consumption. Moreover, it is necessary to minimize the reactive power loss of the motor, so as to improve the natural power factor.

The main purpose of selecting a transformer according to the load is to reduce the reactive power demand in the circuit and improve the natural power factor.

Avoid no-load operation of the motor and reduce the reactive power demand.

2. Labor compensation method.

The artificial compensation method is to use reactive power compensation equipment in the circuit to compensate the reactive power with power capacitors and other equipment. The reactive power generated in the circuit is reduced and the active power output is increased, so as to improve the power factor of the enterprise.

Common reactive power compensation devices include: parallel power capacitors, static reactive power compensators, static reactive power generators, etc. Among them, there are two installation methods of shunt electric fiber search capacitors: local compensation and centralized compensation.

Most companies use parallel power capacitors to compensate for reactive power and improve the power factor.

Improving the power factor can reduce people's electricity bills. Improving the power factor can improve the efficiency of electrical appliances at home and improve the utilization rate of electrical equipment. It can make the current transport faster and reduce the loss in the process of transporting electrical energy.

"Academic education" refers to the form of education in which the educated person has passed the national education examination or other admission methods prescribed by the state, entered a school approved by the relevant state departments or other educational institutions for the re-ordered, and obtained a state-recognized academic certificate. In accordance with the laws and policies on education, and according to whether the educated person has obtained a state-recognized academic certificate, the form of education is divided into academic education and non-academic education. According to the Education Law and other laws and regulations and relevant national regulations, academic education includes the following forms:

Elementary school knowledge, junior high school, high school, junior college education, undergraduate education, graduate education, etc.

The significance of improving the power factor is as follows:

1. Save power grid energy consumption: high power factor can reduce ineffective power consumption, reduce the loss of power grid, and effectively save power generation costs and use costs.

2. Energy saving: high power factor can improve the utilization rate of electric field energy, reduce power loss, save and protect resources.

3. Extend the life of equipment: high power factor can reduce the current and voltage, effectively reduce the temperature rise of equipment and circuits, reduce the failure rate of equipment and circuits, prolong the life of equipment, and reduce maintenance and maintenance costs.

Ways to improve the power factor

1. Compensation capacitors are the most common way to improve the power factor. By connecting the compensation capacitor in parallel to the load circuit, the inductive load and the capacitive load of the power line can be compensated, thereby improving the power factor. The capacitance and type of compensation capacitors need to be selected according to the characteristics of the circuit and the power of the load, and it is necessary to pay attention to factors such as the rated voltage, capacitance and usage environment of the capacitor.

2. The higher the power supply voltage, the greater the current and useless power in the circuit. Increasing the load voltage and decreasing the supply voltage can effectively improve the power factor. This method requires special attention to the rated voltage range of the load appliance and the needs of the load.

3. Inductive load is the main reason for the low power factor in the circuit. Therefore, reducing the inductive load can effectively improve the power factor. Measures can include increasing capacitive loads, adjusting the way core inductors work, etc.

When using inductors, it is a strategy to apply a high-frequency power supply or a high-frequency soft starter or inverter.

4. The power factor of the non-inductive load is usual, so the power factor of the whole circuit can be improved by increasing the non-inductive load. For example, increasing the resistive load, or adding some devices and equipment to non-critical circuits, can increase the non-inductive load and improve the power factor.

5. Upgrading and transforming equipment is also an effective way to improve the power factor, you can replace the old equipment with more efficient equipment, replace the aging wires and cables, copper bars, etc., and use advanced technical equipment or software to improve the operation capacity of the equipment in advance, so as to reduce the overall load of the equipment, extend its service life, and improve the power factor of the entire circuit.

6. The power factor can be improved through a reasonable load collection method. For example, the electrical design of a load group is formed by combining many loads, and the different loads are grouped together, which can reduce the impact on the power supply voltage and current, and reduce the total power factor of the system.