A lightning arrester is an electrical device that can release lightning strikes or power system switching overvoltage energy, protect electrical equipment from instantaneous overvoltage hazards, and cut off freewheeling current to avoid causing a short circuit to the system ground. A lightning protection device connected between a conductor and the ground, usually in parallel with the device to be protected. Lightning arresters can effectively protect electrical equipment. Once abnormal voltage occurs, the arrester will play a protective role. When the voltage is normal, the arrester will quickly return to its original state to ensure normal power supply to the system. Lightning arresters can be used to protect both atmospheric high pressure and operating high voltage.
If there is a thunderstorm, lightning will produce high voltage, and electrical equipment may be in danger. At this time, the lightning arrester will work to protect the electrical equipment from damage. The biggest and most important function of a lightning arrester is to limit overvoltage to protect electrical equipment. A lightning arrester is a device that allows lightning current to flow into the earth so that electrical equipment does not generate high voltage. The main types of arresters are tube arresters, valve arresters and zinc oxide arresters. The main working principles of various types of lightning arresters are different, but their working principles are basically the same, and they are all to protect the equipment from damage.
Lightning arrester installation steps:
1. The installation position of the valve arrester should be as close as possible to the protection equipment. In principle, the shorter the electrical distance between them, the better, so that the protected equipment can be effectively protected. Generally should not be greater than 5mA
2. The arrester is installed on the transformer platform, and its upper lead (power cord) is connected to the lower end of the drop-out fuse. When the drop-out fuse is closed, the arrester and transformer are put into operation at the same time; when the drop-out fuse is open, they stop operating at the same time, so that the arrester is not always at power frequency voltage or switching overvoltage.
3. The arrester must be installed vertically, and the inclination shall not be greater than 50°.
4. There should be enough space around the arrester. The distance between the live part and the adjacent phase conductor or metal frame should not be less than 35m, and the distance between the live part and the adjacent phase conductor or metal frame should not be less than 35m. 35 The distance between the base and the ground should not be less than 2.5m to avoid interference from surrounding objects on the potential distribution of the arrester and reduce the gap discharge voltage.
5. The upper and lower leads of the arrester should be as short and straight as possible, no joints are allowed in the middle, and the connection should be firm. The length of its joints with busbars and conductors should not be less than 100mm. To prevent loosening, tighten with spring washers or double nuts. The leads cannot be too loose or too tight, and no joints are allowed. The cross-section of copper wire is not less than 16mm, and the cross-section of aluminum wire is not less than 25mm.
6. The arrester base is well grounded and insulated, and the ground down conductor is reliably connected to the metal shell of the protected equipment and connected to the universal grounding device.
