Neutral connection: The neutral point of generators and distribution transformers is called the zero point, and the line drawn from the neutral point is called the neutral line. The metal shell of electrical equipment connected to the neutral line is called Neutral connection.

Working grounding: The neutral point of the transformer of the power supply system is directly grounded as the working grounding. The working grounding can ensure the reliable operation of electrical equipment and reduce the human body contact voltage.

Protective grounding: Under normal working conditions of all electrical equipment, the non-charged metal parts are properly grounded as protective grounding. Protective grounding mainly protects the work safety of personnel.

Repeated grounding: Multiple points on the zero line are connected to the ground for multiple times, which is called repeated grounding. When the neutral point is directly grounded in the system, the voltage to the ground can be reduced when the shell is touched or the grounding short circuit occurs; when the neutral line is broken, the damage of the fault can be reduced.

Electrostatic grounding: When equipment moves or objects move in pipelines, static electricity generated by friction accumulates on pipelines, containers, storage tanks or processing equipment, thereby forming a high potential, which poses a threat to personal safety and equipment and buildings. Electrostatic grounding is done, and once static electricity is generated, it is introduced into the ground to eliminate the possibility of its accumulation. A piece of conductive rubber that touches the ground at the rear of a tanker or a car is classified as electrostatic grounding.

DC working grounding: computers and all microelectronic equipment, large-scale integrated circuits, have the same "potential" reference point, connect the "zero" potential point of all equipment to the same grounding device, so that it can stabilize the potential of the circuit and prevent external Interference this kind of grounding is called DC working grounding.