Electric energy has the advantages of easy conversion, economical transmission and convenient control. Therefore, in today's era, whether industrial and agricultural production, national defense construction or even daily life, electricity has increasingly penetrated into all areas of people's activities. Production electricity is produced by power plants. Electric energy needs to be raised to several hundred kilovolts (e.g. 110-200 kv) by step-up substation. It is transported by high-voltage transmission line to the power area, and then distributed to users by substation.
Power system is a whole of generation, supply and use composed of power plants, substations, transmission lines, distribution networks and users.
Power network: The power network is an intermediate link connecting power plants and users, and a device for transmitting and distributing energy. The power network is composed of transmission and distribution lines and transformers of different voltage levels. According to its functions, it is usually divided into two parts: transmission network and distribution network. The transmission network is composed of 35 kV transmission lines and substations connected with them. It is the main network of the power system. Its function is to transfer electric energy to the distribution network in various areas or directly to the users of large enterprises. Distribution network is composed of distribution lines and transformers of 10 kV or less. Its function is to send electric energy to all kinds of users.
Substation: Substation is the hub of receiving and distributing electric energy and changing voltage. It is one of the important links between power plant and users. The substation is composed of power transformer, indoor and outdoor distribution device, relay protection, power device and monitoring system. Substation all boost and buck. Boost substation is usually valley-tied with large-scale power plants. It is equipped with boost transformer in the electrical part of power plants, which increases the voltage of power plants, transmits electric energy to distant places through high-voltage transmission network. The boost substation is located in the power supply center, and supplies power to users in this area after appropriate voltage reduction. Due to the different power supply range, substations can be divided into primary (hub) substation and secondary substation. The substations of factories and enterprises can be divided into total step-down substations (central substations) and workshop substations.
The 6-10kV high-voltage distribution lines from the total step-down substation of workshop substation are electrified, and the voltage is reduced to 380/220v to supply power directly to the electrical equipment.