First, the difference between high pressure and low pressure
Many friends who have recently entered the electrical industry are not very clear about the concept of high voltage and low voltage. Even if they have been friends for many years, they may only touch a part of the large electrical family, and there is not much contact with the professional knowledge of high and low voltage. So, maybe the knowledge in this piece is not very systematic. Today, here to help you sort out this knowledge, for your reference.
1. Let us first look at what is high-voltage electrical appliances
Internationally recognized high and low voltage electrical appliances, the dividing line AC voltage is 1000V (1KV) (DC is 1500V). AC 1000V (1KV) or more is high-voltage electrical appliances, 1000V and below are low-voltage electrical appliances. Transformers are sometimes included in high voltage electrical appliances.
2. Let us take a look at what is low-voltage electrical
A low-voltage electrical appliance is a component or device that can manually or automatically switch circuits on or off according to external signals and requirements to achieve switching, control, protection, detection, transformation, and adjustment of circuits or non-electrical objects. According to the operating voltage of the control electrical appliances, the AC 1000V, DC 1500V is the boundary, which can be divided into two categories: high-voltage control electrical appliances and low-voltage control electrical appliances. In general, low-voltage electrical appliances can be divided into two major categories of distribution and control electrical appliances, which are the basic components of complete electrical equipment. In the process of industry, agriculture, transportation, national defense, and people's use of electricity, most use low-voltage power supply, so the quality of electrical components will directly affect the reliability of low-voltage power supply systems.
Through the above analysis, we must see that the definition of high and low voltage is based on the exchange of 1000V (DC 1500V) as the boundary, simply put, AC 1000V above the high pressure, 1000V below the low pressure; DC and so on.
3. About the popular classification of high-voltage electrical appliances
High-voltage electrical appliances, generally speaking, according to the voltage level, high pressure is divided into medium pressure, high pressure, ultra high pressure, UHV.
Explanation:
1. The dividing line between high pressure and low pressure is 1000V according to the IEC standard, while there is no 1000V voltage level in China, and the dividing line between high pressure and low pressure is actually 3000V.
2. There are no essential differences between the so-called high-voltage, ultra-high-voltage and ultra-high voltage (only with increasing voltage, different insulation requirements and different safety requirements). It is just different people's name. The boundary line is not clearly defined. Therefore, the complete set of electrical reminds you: There will be differences in different versions.
3. In the above table, everyone saw that the nominal voltage of the power grid is lower than the rated low voltage on the equipment. The purpose is to protect the normal operation of the equipment.
The grid nominal voltage and equipment voltage mentioned in the above table, I understand as follows:
1) The rated voltage of the power grid: The power grid refers to the entire power supply and distribution system, including power plants, substations, lines, and power consumers. In China, 10KV, 35KV refers to the rated voltage of the power grid.
2) Rated voltage of electrical equipment: For our country's switches, the rated voltage of our equipment is 12KV, 40.5KV, etc.
Means that the 12KV electric equipment (or switch) should be used for 10KV power grid, 40.5KV power equipment (or switch) should be used for 35KV power grid; because the rated voltage of the electric equipment is higher than the rated voltage of the power grid;
At present, China's commonly used voltage levels: 220V, 380V, 6kV, 10kV, 35kV, 110kV, 220kV, 330kV, 500kV. The power system is generally composed of power plants, transmission lines, substations, distribution lines and electrical equipment. The voltage lines above 35kV and 35kV are usually called transmission lines. Voltage lines of 10kV and below are called distribution lines. Our country provides three kinds of safety voltages: 36V, 24V, and 12V.
Divided according to the standard of China's power grid company: 1KV and below are low voltage, and 1KV or higher is high voltage
Second, the difference between strong electricity and weak electricity
Electricity is something that is indispensable to every family, and the layout of the circuit can't be avoided in the decoration. For the circuit, people often hear people say strong or weak electricity. What is strong electricity? The difference between strong electricity and weak electricity What is it?
The following takes you to learn more about it.
01. About strong electricity: The concept of strong electricity is relative to weak electricity. Strong and weak currents are voltage demarcated. The working voltage is more than 220V AC is strong, and the following is weak.
Strong electric generally refers to alternating voltages above 24V. Such as home lights, sockets, etc., the voltage is 110 ~ 220V. Electrical appliances such as lighting fixtures, refrigerators, televisions, and audio equipment (input terminals) in household electrical appliances are all strong electrical equipment.
Strong Electric Category: Power Engineering (above 10KV) Power Supply and Distribution Project (10KV/380V/220V) are all strong. Strong electrical equipment: high voltage circuit breakers, high voltage cabinets, transformers, sockets and so on. These devices are characterized by operating voltages above 220V.
02. What is a strong box? Strong electric box is the distribution box. The voltage inside the distribution box is generally 380/220V, which is used for electrical energy distribution. The following can be equipped with various electrical equipment such as lights, fans and pumps. The switch box for homes is a kind of distribution box.
03. What is a matching group? The matching group is: a battery with a similar battery capacity and a battery with a similar battery voltage is used in series.
04, strong electricity identification:
(1) Strong electric power does not mean power. A lot of power is used for power, such as motors, air conditioners, and elevators, but power is also used to power computers, TVs, and other devices. Another example is the power of electric vehicles is 12V battery, it can not be called strong electricity.
(2) It cannot be divided by frequency or AC and DC. For example, 800KV DC transmission must be strong.
(3) It is not possible to divide the boundary by the size of the current. The operating current of many high-voltage devices can be very small, while the communication power supply is low-voltage and high-current.
05, strong electricity classification:
Electronic people are used to being divided into two parts: strong electricity (electricity) and weak electricity (information). The two are both related and different. In general, the object of processing the strong current is energy (electricity). Its characteristics are high voltage, large current, large power, and low frequency. The main considerations are reducing losses, improving efficiency, and weak currents. The main object of the processing is information, that is, information transmission and control. Its characteristics are low voltage, low current, low power, and high frequency. The main consideration is the effect of information transmission, such as the fidelity, speed, and breadth of information transmission. ,reliability. In general, weak current projects include television engineering, communications engineering, fire engineering, security engineering, imaging engineering, etc., and integrated wiring works for the above-mentioned projects. Weak electricity is for strong electricity. Strong electricity = (380/220), no matter high pressure.
06, the use of strong electricity:
In power systems, voltages below 36V are called safe voltages, voltages below 1kv are called low voltages, voltages above 1kv are called high voltages, and lines that directly supply power to users are called distribution lines, such as user voltages are 380/220v, It is called a low-voltage distribution line, which is the strong electricity in home decoration (because it is the highest voltage for home use). Strong electric generally refers to alternating voltages above 24V. Such as home lights, sockets, etc., voltage 110V ~ 220V. Household electrical lighting, electric water heaters, heaters, refrigerators, televisions, air conditioners, audio equipment and other electrical appliances are strong electrical equipment.
07, the difference between strong and weak electricity:
Strong electricity generally refers to the installation of electrical power in buildings, lighting, sockets, and power distribution rooms. According to the standards of various countries, basically 110V or 220 electrical equipment and pipelines are installed.
Weak electricity refers to such types of work as firefighting and intelligence. Generally, equipment used for electricity installation is basically low-voltage electricity, including fire protection, internet, radio, building intercom, security monitoring, and building automation.
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