Electric power knowledge sharing

1. What is active/reactive work?

In the process of transmission and use of alternating current energy, the part of energy used to convert into non-electric and magnetic forms (such as light, heat, mechanical energy, etc.) is called active work. The part of energy used for the exchange of electricity and magnetic fields within the circuit is called reactive power. Any electrical equipment with electromagnetic coils must occupy reactive power to establish a magnetic field.

For example, a 40-watt fluorescent lamp requires not only 40 watts of active power to emit light, but also about 80 watts of reactive power for the ballast coil to create an alternating magnetic field.

2. What is current? How is the direction of current determined?

Electric current: refers to the regular movement of free electrons or ions under the action of electric field force, which is called electric current.

It is stipulated that the direction of movement of positive charges is the direction of current flow, and the direction of movement of free electrons is opposite to the direction of current flow.

3. What is the difference between weak electricity and strong electricity?

Electric power applications can be divided into two categories: strong electricity and weak electricity according to the strength of the power transmission power.

The electricity used in buildings and building complexes generally refers to strong electricity of AC 220V50Hz and above. Strong electricity is transmitted through transmission lines, which mainly provides electric energy to people and converts electric energy into other energy sources, such as air-conditioning electricity, lighting electricity, power electricity, etc.

There are two main types of weak electricity in smart buildings. One is low-voltage electric energy such as safety voltage level and control voltage stipulated by the country. It is divided into AC and DC, AC below 36V and DC below 24V, such as 24V DC control power supply, or emergency power supply. Backup power supply for lights. The other type is information sources carrying voice, image, data and other information, such as telephone, television, and computer information. People are accustomed to refer to weak current technology as weak current technology. Weak current transmission can be divided into wired and wireless transmission, while radio transmits by electromagnetic waves.

4. What is the main role of transformers in power systems?

The role of transformers in power systems is to convert voltage to facilitate power transmission. After the voltage is boosted by the step-up transformer, line losses can be reduced, the economy of power transmission can be improved, and the purpose of long-distance power transmission can be achieved. The step-down transformer can convert high voltage into various levels of voltage required by users to meet user needs.

5. What is the function of current transformer?

Current transformers convert large currents into small currents in a certain proportion, provide current for various instruments and relay protection, and isolate the secondary system from high voltage. It not only ensures the safety of people and equipment, but also simplifies and standardizes the manufacturing of instruments and relays, and improves economic benefits.

6. What is the significance of improving the power factor of the power grid?

Most of the electrical equipment used in production and life are inductive loads, and their power factors are low. This will cause the power generation equipment to be unable to be fully utilized and increase the losses on the transmission lines. After the power factor is improved, the power generation equipment can generate less electricity. Instead of reactive load, more active load can be transmitted, which can also reduce losses on power generation equipment and save electric energy.

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