The main function of substation system is to raise or reduce primary side voltage by transformer, and then transmit it through secondary side. Raising the voltage is to reduce loss in long-distance transmission of electric energy, like 500kV high voltage transmission etc. Reducing voltage is for the use purpose of respective voltage level load of client end, like civil 220v, industrial 380v, 660v, 690v, 1000v, 6kV, 10kV etc. Core components of substation system are transformer, conductor, insulator, transformer, arrestor and breaker etc.

Transformer
      Transformer is divided into two categories of voltage transformer and current transformer. Its main functions are: transmitting voltage, current information of primary system appropriately to respective equipment of secondary side; converting high voltage, heavy current of primary system to low voltage (standard value), low current (standard value) of secondary side. Standardizing and miniaturizing devices like measuring, metering instrument and relay etc. to ensure safety of secondary equipment and person.

Reactor
      Series reactor and shunt reactor are commonly applied in electric power system. Series reactor is mainly used to limit short circuit current. Some in wave filter are also in series connection or parallel connection with capacitor to limit upper harmonics in network. Shunt reactor is used to absorb reactive capacity of network. Supervoltage shunt reactor has various functions, which may improve respective running condition of electric power system reactive power.

Insulator
      Insulator is a special kind of insulation device, which is used to support or hang high voltage conductor and isolate them from earth. Because that electric ceramic insulator is wind-proof, heat-proof and rain-proof, its insulation performance is comparatively stable. Therefore high voltage electric ceramics are widely applied for miscellaneous high voltage transmission and transformation equipment as insulation. (especially for outdoor purpose).

Switchgear
      Main function of switchgear is connecting or isolating two electrical systems. High voltage switch is a kind of electric machinery, which is used to complete connection and switching off of electric circuit to achieve conversion, controlling and protection of electric circuit.

Arrester
      Arrestor is mainly used to protect substation electrical equipment from being damaged by lightning. Arrestor is mainly installed at inlet and outlet ends of substation transmission line. When voltage of lightning wave coming from transmission line exceeds a certain amplitude, the arrester shall act primarily to relieve partial lightning current through ground net and itself to earth to protect electrical equipment.