Power network: classification according to the level of voltage level and the size of power supply range
Local power grid: voltage level is 35kV and below, power supply radius is within 20~50km
Regional power network: voltage level is above 35kV (generally 110kV~220kV), power supply radius is more than 50km, contact network of more power plants
Ultra-high-voltage long-distance transmission network: The network with voltage level of 330kV~500kV, its main task is to transport the electric energy produced by distant power plants to the load center, and also contact several regional power networks to form large-scale power systems across provinces and regions.
Substation: classified according to its position in the power system
Terminal power station:
The rated voltage of the generator set output of China's power plants is 3.15~20KV. With the completion of large-scale power plants and the increase of transmission distance, in order to reduce the line energy consumption, pressure drop, and save non-ferrous metals and reduce the cost of line engineering, it must be boosted to 35-500KV by the booster substation in the power plant. Then, it is transmitted to the substation of the receiving area by the high-voltage transmission line, and is stepped down to 6~10KV. It is sent to the user's distribution substation through the high-voltage distribution line and stepped down to 220/380V low voltage for use by the electric equipment.