There are four common electrical grounding methods:

1.Working Grounding

Working grounding, also known as system grounding, is grounding a certain point of the network according to the needs of the normal operation of the power system. For example, the neutral point of three-phase system is grounded to stabilize the potential of the grid to the ground, thus reducing the insulation to the ground. It can also make the flashover or breakdown of ground insulation easy to detect, and is conducive to the implementation of relay protection measures.

2. Protective grounding

Protective grounding is also called safe grounding. The metal case of electrical devices, the structure of distribution devices and the tower of transmission lines may be charged due to insulation damage. The grounding is set up to prevent it from endangering the safety of people and equipment.

3. Lightning Protection and Grounding

This is to make the strong lightning current safely into the ground, to reduce the potential rise caused by the outdated lightning current, such as lightning rod, lightning wire and arrester grounding.

4.Antistatic Grounding

Grounding is designed to prevent the dangerous effects of static electricity on flammable and explosive substances such as flammable oil, natural gas storage tanks and pipelines.

Generally speaking, the function of grounding can be divided into two parts: The one protecting personnel and equipment from damage is called protective grounding; The one ensuring the normal operation of equipment is called working grounding. The classification here refers to various requirements considered in the design and construction of grounding engineering, and does not mean that each "ground" needs to be separated. On the contrary, in addition to the special reasons such as anti-interference of geoelectric signals and special requirements of equipment itself, we advocate the joint grounding scheme as far as possible.