At present, the commonly used voltage levels in China are: 220V, 380V, 6kV, 10kV, 35kV, 10kV, 220kV, 330kV, 500kV, 1000KV. Power system is generally composed of power plants, transmission lines, substations, distribution lines and electrical equipment. Voltage lines above 35kV are usually called transmission lines.

Voltage can be divided into high voltage, low voltage and safe voltage.

The difference between high voltage and low voltage is based on the voltage value of electrical equipment to ground. The voltage to ground is higher than or equal to 1000 volts. The voltage to ground is lower than 1000 volts.

Among them, safe voltage refers to the voltage that the human body contacts for a long time without the danger of electric shock. According to the national standard "GB3805-83", safe voltage stipulated the voltage series provided by specific power sources to prevent electric shock accidents. China has stipulated the following five grades for power frequency safe voltage, namely, 42V, 36V, 24V, 12V and 6V.

The extended data safe voltage is defined as 36V, 24V, 12V in China.

Among AC voltage levels, 1kV and below are usually called low voltage, 1kV and 20kV and below are called medium voltage, 20kV and below 330kV are called high voltage, 330kV and above, and 1000kV and above are called extra high voltage.

In the DC voltage class, the voltage below 800 kV is called high voltage, and the voltage above 800 kV is called UHV.

References:

Baidu encyclopedia-voltage