Electrical primary equipment can be divided into six categories according to their role in production:

1. Equipment for the production and conversion of electrical energy. For example, generators convert mechanical energy into electrical energy, motors convert electrical energy into mechanical energy, transformers increase or lower voltage, etc., to meet the needs of power transmission and distribution.

2. Switch electrical appliances that turn on or off circuits. Such as circuit breakers, disconnectors, fuses, contactors, etc. They are used to close or disconnect circuits when the power system is normal or in an accident state.

3. Electrical appliances that limit fault current and prevent overvoltage. Such as reactors that limit short-circuit current and lightning arresters that prevent overvoltage.

4. Grounding device. It is a metal conductor buried in the ground that is in direct contact with the earth and a metal wire connected to electrical equipment. Whether it is the working grounding of the neutral point of the power system or the protective grounding to protect personal safety, it is connected to the grounding device buried in the ground.

5. Current-carrying conductor. Such as bare conductors, cables, etc. According to the design requirements, the relevant electrical equipment is connected.  

6. Conversion equipment between AC electrical primary and secondary equipment. Such as voltage and current transformers, through which the voltage and current on the primary side are converted to the secondary system.