First, function positioning

Switching station: mainly used for power system transmission and distribution links, the main task is to switch control of power to achieve the transmission and distribution of electric energy. It can selectively connect or disconnect the power system (grid) and its users' electrical equipment through switching devices, so as to distribute high and medium voltage electrical energy.

Substation: It is responsible for converting high-voltage electrical energy into low-voltage electrical energy to meet the needs of users. Substation not only for voltage conversion, but also through transformers and other equipment to achieve the transformation, distribution and transmission of electric energy, while controlling voltage, frequency, power factor, etc., to improve the stability and quality of electric energy.

Second, structure composition

Switch station: The structure is relatively simple, mainly including incoming switch, outgoing switch, bus, transformer, arrester and other equipment. It has no power transformer, but the power system is controlled and protected by switching equipment.

Substation: The structure is more complex, including high voltage switch, transformer, low voltage switch, reactive power compensation device and other equipment. The substation converts high-voltage electrical energy to low-voltage electrical energy through transformers, and distributes the electrical energy to different circuits through various switchgear and distribution methods.

Third, equipment selection and automation level

Switching station: The equipment selection mainly considers its switching capacity and short circuit capacity to ensure that the fault current can be quickly cut off when the power system fails and the safety of the power system is protected. Although the switching station has gradually realized automated operation, its level of automation is relatively low.

Substation: Equipment selection needs to consider the capacity of the transformer, voltage level, short-circuit impedance and other factors to meet the power needs of the power system. Substation usually adopts integrated automation system to realize real-time monitoring, fault diagnosis and remote control of equipment, and has a high level of automation.