There are two main reasons for the failure of lightning arresters:
Reason 1: Poor sealing
Common lightning protection devices are mainly used to prevent damage to electrical equipment in substations caused by lightning waves. It not only has excellent nonlinear volt-ampere characteristics, but also has characteristics such as low cost, no gap, no afterflow, high flux, and stable performance. However, sometimes accidents such as malfunctions and explosions can occur. The common faults are mainly caused by poor sealing.
Cause analysis:
Poor sealing of zinc oxide lightning arrester is mainly caused during the production process of the product. For example, the zinc oxide lightning arrester valve plate is not completely dry and contains moisture. Or the gasket of the lightning arrester may be improperly positioned or even installed during the assembly process. Some manufacturers use substandard materials. For example, using inferior porcelain jars with invisible holes allows moisture to seep in and make the interior moist.
Preventive measures:
To prevent the lightning arrester from being poorly sealed, users should conduct strict sealing tests before use. In addition, during the operation and maintenance of zinc oxide lightning arresters, especially after thunderstorms, it is necessary to strengthen the inspection of the lightning arresters and promptly detect abnormalities. When using a zinc oxide lightning arrester tester for regular preventive testing of lightning arresters, testers must carefully analyze the test data. Because when the lightning arrester is damp, there may be no external issues, but only through testing data can internal defects be discovered.
Reason 2: Internal valve plate aging
Cause analysis:
Valve plate aging generally occurs during operation. Due to poor uniformity and varying degrees of aging of the lightning arrester valve plate, it can lead to uneven potential distribution of the valve plate. After running for a period of time, some valves will deteriorate first, leading to an increase in the leakage current of the lightning arrester and an increase in power loss. Due to the constant voltage of the power grid, the remaining normal valves in the zinc oxide lightning arrester are heavier, resulting in faster aging. This creates a vicious cycle, ultimately leading to explosion accidents inside the zinc oxide lightning arrester, single-phase grounding, or the main body of the lightning arrester. Another reason for the accelerated aging of zinc oxide lightning arrester valves is that the zinc oxide lightning arrester continues to operate under low voltage. This will lead to a significant increase in load on zinc oxide lightning arresters during operation, especially when the system is single-phase grounded, resulting in rapid aging of the valve blades.
Preventive measures:
In response to the aging problem of zinc oxide lightning arrester valves, in addition to requiring manufacturers to improve production processes and improve valve uniformity, it is also necessary to select lightning arresters with sufficient rated voltage and continuous working voltage. Design and selection. In addition, during the inspection, not only should the appearance of the lightning arrester be checked for damage and flashover phenomena, but also the leakage current value of the lightning arrester should be recorded and compared with the initial value. If the value is too large, defects should be reported and dealt with in a timely manner.
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