In the power system, the system works under the rated voltage under normal conditions, and the voltage deviation is very small. All electrical equipment is working normally. However, when the system is struck by lightning or malfunctions, the system voltage will rise a lot, and the grid voltage will go out of the normal voltage instantaneously. Several times or even dozens of times. In this case, the insulation of all system equipment will be unable to withstand, breakdown or even be In the dormant state, once the system has overvoltage, it will immediately activate and enter the working state, instantly turning itself into a conductor, releasing the high voltage to the ground, avoiding the continuous rise of the system voltage, and protecting the equipment and personal safety.
Lightning arresters can effectively protect power equipment. Once an abnormal voltage occurs, the arrester will work and play a protective role. When the protected equipment is running under the normal working voltage, the arrester will not have any effect, and it is regarded as open circuit to the ground. Once high voltage occurs and the insulation of the protected equipment is endangered, the arrester will act immediately to direct the high-voltage impulse current to the ground, thereby limiting the voltage amplitude and protecting the insulation of electrical equipment. When the overvoltage disappears, the arrester quickly returns to its original state, enabling the system to supply power normally. The main function of the arrester is to clip the intrusion flow wave through the parallel discharge gap or nonlinear resistance, reduce the overvoltage value of the protected equipment, so as to protect the power equipment. Lightning arresters can be used not only to protect against atmospheric high voltages, but also to protect operating high voltages.