【Weekly Topic】Week 12 of 2011: What are the advantages of zinc oxide arresters?
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This post was last edited by siena2008 on 2011-3-21 18:23. [Weekly Topic 20110319] What are the advantages of zinc oxide arresters? Answer: (1) No gap, no freewheeling. At the operating voltage, the ZnO valve element exhibits a very high resistance, with a nearly zero freewheeling current; it behaves like an insulator. As a result, prolonged exposure to the operating voltage does not cause damage to the valve element, so it is generally not necessary to use a series gap to isolate it from the operating voltage. (2) Large flow capacity. Due to the extremely low freewheeling energy, which absorbs only the energy of inrush currents, the current-carrying capacity of ZoO arresters is high ； It is more suitable for limiting internal overvoltages that have a longer duration (compared to atmospheric overvoltages). (3) It can reduce the overvoltage experienced by electrical equipment. Under the same lightning current and the same residual voltage, a ZnO arrester (without a series gap) allows current to flow during the rise of the wave front, which helps to reduce the overvoltage applied to the equipment. (4) In terms of insulation coordination, it is possible to achieve nearly identical protection margins for steep waves, lightning waves, and switching waves. (5) ZnO arresters are small in size, light in weight, simple in structure, and easy to operate and maintain.
A zinc oxide arrester is a metal-oxide-semiconductor nonlinear resistance component whose main component is zinc oxide； Resistance is sensitive to voltage; when the voltage reaches a certain level, the resistance conducts electricity rapidly. Zinc oxide arresters possess excellent non-linear characteristics, high current-carrying capacity, low residual voltage levels, fast response times, and no backflow. The disadvantage is leakage current, which can cause the device to age prematurely. Zinc oxide arresters are small in size but have a high leakage current; they are generally used on electrical lines as well as at the low- and medium-voltage input terminals of substations.
A zinc oxide arrester is an arrester that contains no discharge gap and is composed solely of zinc oxide (ZnO) resistive elements. These zinc oxide resistive elements exhibit excellent nonlinear characteristics; under normal operating voltage, only a few hundred microamps of current flows through them, allowing them to operate under voltage for extended periods. When overvoltage occurs, the resistance of these resistive elements decreases rapidly, causing the current flowing through them to increase sharply. This helps to limit the amplitude of the overvoltage and dissipate its energy. Moreover, it has a lower residual voltage compared to conventional valve-type arresters. Therefore, it is a protection device for power station equipment that offers many more advantages than conventional valve-type arresters
Reply to 1# zhaohh3211: It not only possesses the advantages of porcelain-clad metal oxide arresters, but also features good electrical insulation properties, high dielectric strength, resistance to tracking, resistance to electrochemical erosion, heat resistance, cold resistance, aging resistance, explosion protection, water repellency, and excellent sealing properties.