What is the voltage level of the power grid and the level of ultra high voltage

Ultra-high voltage grids refer to 330kV, 500kV and 750kV grids.

At present, for the vast majority of power grids in China, high-voltage power grids refer to 110kV and 220kV power grids; Ultra-high voltage grids refer to 330kV, 500kV and 750kV grids. UHV transmission.

Refers to the 1000 kV AC and 800kV DC transmission engineering and technology that are being developed.

UHV power grid refers to a modern large power grid with 1000kV transmission network as the backbone grid, ultra-high voltage transmission network and high-voltage transmission network, as well as UHVDC transmission and distribution network.

AC 500kV (inclusive) or more, the existing voltage in addition to 500kV, and the above is UHV.

DC is plus or minus 500kv to 800kv, and 800kv and above is UHV.

More than 1000V is called high voltage, more than 500KV is called ultra-high voltage, and more than 750KV is called UHV.

It should be clear that it is the voltage level of AC, and the voltage level of DC is different.

If a cable is used, the voltage level is different.

The 500kV submarine AC cable belongs to UHV.

GBT Electrician Terminology Generation, Transmission & Distribution General Terminology.

The definition specifies the range of low-voltage electricity.

The range of high-voltage electricity is specified in Appendix A.

It is divided into the following categories, which are:

1. Talk about return voltage safely.

It is usually below 36V.

2. Low voltage, generally 220V and 380V.

3. High pressure, energy is often between 10kV and 220kv.

4. Ultra-high voltage, which is between 330kV and 750kv.

5. Stir Hu high voltage.

1000kV AC, 800kV DC or above.

China stipulates that the safety voltage is 42V, 36V, 24V, 12V, and 6V.

In the AC voltage level, 1kV and below are usually called low voltage, above 1kV, 35kV and below are called medium voltage, above 35kV and below 220kV are called high voltage, 330kV and above, below 1000kV are called ultra-high voltage, and 1000kV and above are called UHV.

In the DC voltage level, 800kV or less is called high voltage, and 800kV and above is called UHV.

There are four levels of low pressure, medium pressure, high pressure and extra high. The rated voltage of the power grid refers to the rated voltage of the power line and the bus of the substation connected to it.

Because there is a voltage drop after the power line passes through the current, the voltage at the beginning of the power line U1 is greater than the terminal voltage U2. Generally, it is stipulated that the terminal voltage is allowed to drop by 10% compared to the first voltage.

Rated voltage of power line: un=(u1+u2) 2.

The rated voltage of the electrical equipment connected to the power line is the same as the rated voltage.

Rated voltage of electrical equipment: The rated voltage of electrical equipment is the same as that of the power grid of the same level.

When the electrical equipment is operated at the rated voltage, it has the greatest benefits and the longest life.

The operating voltage of the electrical equipment is allowed to have a 5% change range, which is compatible with the 5% change of the rated voltage at the beginning and end of the power line.

The rated voltage of the generator: 5% higher than the rated voltage of the same level of power grid.

Reason: The generator is connected to the head of the power line, and the rated voltage of the grid at the same level should be 5% higher than the rated voltage of the same level according to the regulations.

The voltage level of the power system is divided into two parts: the transmission network and the distribution network.

1. Power transmission network.

According to the "Design Rules for the Provisions of the Urban Power Grid", the transmission network voltage:

UHV: 1000kV, 750kV;

Ultra high voltage: 500kV, 330kV;

High voltage: 220kV, 110kV.

2. Power distribution network.

High-voltage distribution network voltage: 110kv, 66kv;

Medium voltage distribution network voltage: 20kv, 10kv, 6kv;

Low-voltage distribution network voltage:.

The voltage level is generally divided:

1: Safe voltage (usually below 36V);

2: Low voltage (divided into 220V and 380V);

3: High voltage (10kv-220kv);

4: Ultra-high voltage 330kv-750kv;

5: UHV 1000kV AC, 800kV DC or above.

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

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

Among them, the safe voltage refers to the voltage that the human body is exposed to for a long time without the risk of electric shock. According to the national standard "GB3805-83" safety voltage, the voltage series used to prevent electric shock accidents and supplied by a specific power supply is specified. China stipulates the following five levels for power frequency safety voltage, namely 42V, 36V, 24V, 12V and 6V.

The voltage level of the power system is divided into two parts: the transmission network and the distribution network.

1. Power transmission network.

According to the "Design Rules for the Provisions of the Urban Power Grid", the transmission network voltage:

UHV: 1000kV, 750kV;

Ultra high voltage: 500kV, 330kV;

High voltage: 220kV, 110kV.

2. Power distribution network.

High-voltage distribution network voltage: 110kv, 66kv;

Medium voltage distribution network voltage: 20kv, 10kv, 6kv;

Low-voltage distribution network voltage:.

The voltage level is divided into safety voltage, low voltage, high voltage, ultra-high voltage, and ultra-high voltage power network rated standard voltage (kv).

Low pressure (high pressure (ultra-high pressure)

UHV).

The voltage level of the power system is 220 380V (3kv, 6kv, 10kv, 20kv, 35kv, 66kv, 110kv, 220kv, 330kv, 500kv, etc.

With the improvement of the motor manufacturing process, 10kV motors have been mass-produced, so 3kV and 6kV have been used less, and 20kv and 66kv are rarely used. The power supply system is mainly 10kV and 35kV, and the transmission and distribution system is mainly above 110kV. There are two kinds of generators in power plants: 6kV and 10kV, and now 10kV is the mainstay, and the users are 220 380V (low-voltage system.

According to the "Urban Power Network Design Rules", the transmission network is 500kV, 330kV, 220kV, 110kV, the high-voltage distribution network is 110kV, 66kV, the medium-voltage distribution network is 20kV, 10kV, 6kV, and the low-voltage distribution network is.

The power plant sends out 6kV or 10kV electricity, in addition to the power plant's own use (plant electricity), it can also be sent to users near the power plant with 10kV voltage, 10kV power supply range is 10km, 35kV is 20 50km, 66kV is 30 100km, 110kV is 50 150km, 220kV is 100 300km, 330kV is 200 600km, 500kV is 150 850km.

The various voltage levels of the power system are converted by power transformers, the voltage is increased into a step-up transformer (the substation is a step-up station), and the voltage is reduced to a step-down transformer (the substation is a step-down station).

A two-turn transformer with two coils (windings) is used to change one voltage to another, and a three-turn transformer with three coils (windings) is used when one voltage becomes two voltages.

The voltage level is generally divided: safety voltage (usually below 36V); Low voltage (220V and 380V again).

Since the 20th century, it has been widely recognized that expanding the scale of the power system can bring obvious social and economic benefits in terms of energy development, industrial layout, load adjustment, system safety and economic operation.

As a result, the size of the power system has grown rapidly. The largest power system in the world is the unified power system of the former Soviet Union. It spans 7,000 kilometers from east to west and 3,000 kilometers from north to south, covering about 10 million square kilometers of land.

Reasonable configuration of the voltage level of the urban power grid:

1) With the growth of load, the adaptability of the current voltage level sequence in some parts of China is limited, and it is necessary to adopt a new voltage level sequence. The implementation plan of the voltage level configuration needs to be carried out in depth according to the specific situation of the city.

2) For areas with higher final load density, consider gradually transitioning to a higher medium-voltage distribution voltage. For areas with low final load density and long supply distances, higher medium-voltage distribution voltages can also be considered.

3) In order to avoid affecting the reliability of power supply in the process of introducing new voltage levels, the power grid of different distribution voltage levels can be connected to the grid by installing a liaison transformer.

The common voltage levels of China's power system are as follows: safety voltage 12V, 24V, 36V.

DC 110V, 220V, 800KV (for DC transmission), AC 380V, 3KV (for some old enterprise power), 6KV (for power sector), 10KV, 35KV, 60KV (for Northeast China), 110KV, 220KV, 330KV (for Northwest China), 500KV, 750KV, 1000KV, 1200KV

Generator voltage 380V, 3kV, 6kV, 10kV, ,20kV, 24kV

Electricity Grid (Transmission. Change. At present, AC power frequency 50Hz voltage is commonly used, transmission ultra-high voltage 350kV, 500kV, high voltage 110kV, 220kV, power distribution has 35K, 10kV,,, low voltage, etc.

Low voltage: less than 1kV, commonly used in residential or small commercial customers to utility distribution lines;

Zhongqing Wang voltage grinding (distribution): between 1kV and 33kV, used for power distribution in urban and suburban areas;

High Clearance Voltage (Transmission): Higher than 33kV, Lower than 230kV;

Ultra-high voltage (transmission): above 230kV, below 800kV for long-distance and very high-performance transmission;

Ultra-high voltage (transmission): above 800kV.

The highest voltage level of China's current power system: AC 1000kV, DC 800kV.

In China's power system, the AC voltage level with a nominal voltage of 1kV and below is defined as low voltage, the AC voltage level with a nominal voltage of more than 1kV and below 330kV is defined as high voltage, and the nominal voltage of 330kv and above and below 1000kv is defined as ultra-high voltage.

The AC voltage level with a nominal voltage of 1000kV and above is defined as UHV, the DC voltage level with a nominal voltage of 800kV or less is defined as HVDC, and the DC voltage level with a nominal voltage of 800kV or more is defined as UHVDC.

There is usually a name for "medium voltage", the American Institute of Electrical and Electronics Engineers (IEEE) standard document to 69 kV voltage level is called Hu Sou medium voltage, China's State Grid Corporation (SG) normative document Hongsong more than 1kV to 20kV voltage level is called medium voltage.