Author: Noyafa–CCTV Monitor Tester
Grounding cable grounding encyclopedia grounding cable grounding (earthing) grounding refers to the neutral point of power systems and electrical devices, the exposed conductive parts of electrical equipment and the conductive parts outside the device are connected to the earth through conductors. It can be divided into working grounding, lightning protection grounding and protective grounding. The working ground is set by the operation of the power system (such as the neutral point grounding), so under normal circumstances, there will be current flowing through the ground electrode for a long time, but it is only an unbalanced current of several amperes to tens of amperes.
When a ground fault occurs in the system, a working current of thousands of amperes will flow through the ground electrode, but the current will be cut off by the relay protection device within 0.05~0.1s, even if it is a backup protection, the action is generally within 1s. The lightning protection grounding of the grounding cable is a grounding set up to eliminate the dangerous influence of overvoltage, such as the grounding of lightning rods, lightning conductors and lightning arresters. Lightning protection grounding can only flow current under the action of lightning strike. The amplitude of lightning current flowing through the lightning protection grounding electrode can reach tens to hundreds of thousands of amperes, but the duration is very short.
Protective grounding is a grounding set to prevent equipment from endangering personal safety due to insulation damage, such as metal casings, reinforced concrete poles and metal towers of electrical equipment. The protective grounding will only flow current when the equipment insulation is damaged, and its value can vary within a wide range. When the grounding cable current flows through the above three grounding electrodes, the potential of the grounding electrode will rise, which will affect the safety of people and equipment.
Therefore, the potential rise of the ground electrode must be limited, or corresponding safety measures must be taken to ensure the safety of equipment and personnel. Shenzhen Noyafa Electronic Technology Co., Ltd. is a high-tech enterprise engaged in scientific research, production and sales, and provides technical services for cable fault detection. At present, a variety of high-voltage test equipment and testing instruments have been widely used in the industry. At the same time, our company provides technical services such as cable fault detection and substation testing and testing to users across the country. The core engineer responsible for providing technical services has 20 years of on-site testing. Experience, can provide solutions according to different types of cables and site environment.
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