How does the lightning arrester respond to overvoltage quickly with its precise voltage sensing elements?
Publish Time: 2024-12-11
In power and electrical systems, the lightning arrester has the important mission of protecting equipment from lightning overvoltage and operational overvoltage. Its precise voltage sensing elements are the core of achieving rapid response to overvoltage.
The voltage sensing elements in the lightning arrester are usually made of materials with nonlinear resistance characteristics such as zinc oxide valve plates. Under normal operating voltage, these sensing elements present extremely high resistance, which is equivalent to an open circuit state, with only a small leakage current passing through, which has almost no effect on the normal operation of the power system. However, when overvoltage occurs in the system, whether it is a transient ultra-high voltage caused by direct lightning strikes or induction, or a sudden voltage change caused by internal operations of the power system (such as switch operations, fault tripping, etc.), the voltage sensing element can keenly sense the abnormal increase in voltage.
This is because the resistance value of the zinc oxide valve plate changes dramatically with the change of voltage. When the voltage exceeds its threshold, the resistance of the valve plate decreases rapidly, changing from a high resistance state to a low resistance state, causing the lightning arrester to turn on quickly. This transition from high resistance to low resistance is extremely rapid and can be completed in nanoseconds. For example, when struck by lightning, the instantaneous increase in voltage causes the zinc oxide valve plate to react almost immediately, quickly forming a low-resistance path, allowing the current generated by the overvoltage to be discharged to the ground through the lightning arrester instead of flowing into the protected electrical equipment, thereby effectively protecting the insulation system of the equipment from damage by excessive voltage.
In order to ensure the accuracy of the voltage sensing element, the material formula, production process and structural design of the element are strictly optimized and precisely controlled during the manufacturing process. Advanced material preparation technology is used to precisely control the purity, particle size and doping ratio of raw materials such as zinc oxide, so that the valve plate has stable and predictable voltage-current characteristics. At the same time, in the structural design of the element, considering the uniformity of the electric field distribution, the special electrode shape and layout are used to ensure that the sensing element can accurately start and play a protective role under the overvoltage of different voltage levels and waveforms. In addition, the lightning arrester is also equipped with a sophisticated monitoring and diagnostic system that can monitor the performance status of voltage sensing elements in real time. Once changes in its characteristics or potential faults are found, an early warning signal is issued in time to allow maintenance personnel to carry out inspections or replacements. This ensures that the lightning arrester can always respond quickly to overvoltages at critical moments with its precise voltage sensing elements, safeguarding the safe and stable operation of power and electrical systems.
