The lightning arrester is a kind of lightning protection device used to prevent the lightning wave from invading the substation and damaging the electrical equipment. Under the normal working voltage, the arrester gap will not be broken, and the leakage current flowing through the arrester is very small. When a lightning wave strikes, the arrester gap will soon be broken down and discharged to the ground, limiting the overvoltage value of the protected equipment and protecting the equipment.
Zinc oxide surge arresters are widely used in 10 kV voltage scale power grids. It not only has excellent nonlinear volt-ampere characteristics, but also has low cost, no gap, no freewheeling, large flow capacity, and stable performance. However, accidents such as breakdowns and explosions also occurred. For this reason, the author published his own opinions on the common faults and preventive measures of zinc oxide surge arresters.
Bad seal
Analysis of reasons: The bad seal of the arrester is mainly caused by the production process of the product. Such as lightning arrester valve drying is not complete, moisture content. Or when assembling, the gasket of the arrester is not properly positioned or even installed. Some manufacturers use unsatisfactory materials, such as the use of poor quality porcelain bottles, with invisible holes will also cause water infiltration, so that the internal moisture.
Precautionary measures: In order to prevent the arrester from being poorly sealed, the user should conduct a strict seal test before use. In addition, during the operation and maintenance of the arrester, especially after a thunderstorm, it is necessary to strengthen the inspection of the arrester to detect abnormal conditions in time. When conducting regular preventive tests on arresters, testers must carefully analyze the test data. When the arrester is wet, it may not show any problems in its appearance, but the internal defects can only be found through the test data.
Internal valve aging
Analysis of the causes: The aging of the valve plate generally occurs during operation. Due to the poor uniformity of the arrester valve, the degree of aging is not the same, it will make the valve potential distribution uneven. After a period of operation, some of the valve plates deteriorate first, causing the arrester leakage current and power loss to increase.
As the grid voltage is constant, the burden on the rest of the normal valves in the surge arrester increases, resulting in an accelerated aging rate. In this way, a vicious circle is formed, which eventually leads to internal breakdown of the lightning arrester and single-phase grounding or arrester body explosion.
Another cause of accelerated aging of the zinc oxide surge arrester is the low operating voltage of the arrester. This will cause the operation of the process, especially when the system occurs single-phase grounding, will greatly increase the arrester load, resulting in rapid aging of the valve.
Precautionary measures: In addition to asking the manufacturer to improve the production process and improve the uniformity of the valve plate, the arrester should be equipped with a surge arrester with sufficient rated voltage and continuous operating voltage.
In addition, during inspections, not only the appearance of the arrester should be checked for broken flashovers, but also the value of the leakage current of the arrester should be copied and compared with the initial value. If the value is too large, the defect should be promptly reported and treated. .
Zinc oxide surge arresters are widely used in 10 kV voltage scale power grids. It not only has excellent nonlinear volt-ampere characteristics, but also has low cost, no gap, no freewheeling, large flow capacity, and stable performance. However, accidents such as breakdowns and explosions also occurred. For this reason, the author published his own opinions on the common faults and preventive measures of zinc oxide surge arresters.
Bad seal
Analysis of reasons: The bad seal of the arrester is mainly caused by the production process of the product. Such as lightning arrester valve drying is not complete, moisture content. Or when assembling, the gasket of the arrester is not properly positioned or even installed. Some manufacturers use unsatisfactory materials, such as the use of poor quality porcelain bottles, with invisible holes will also cause water infiltration, so that the internal moisture.
Precautionary measures: In order to prevent the arrester from being poorly sealed, the user should conduct a strict seal test before use. In addition, during the operation and maintenance of the arrester, especially after a thunderstorm, it is necessary to strengthen the inspection of the arrester to detect abnormal conditions in time. When conducting regular preventive tests on arresters, testers must carefully analyze the test data. When the arrester is wet, it may not show any problems in its appearance, but the internal defects can only be found through the test data.
Internal valve aging
Analysis of the causes: The aging of the valve plate generally occurs during operation. Due to the poor uniformity of the arrester valve, the degree of aging is not the same, it will make the valve potential distribution uneven. After a period of operation, some of the valve plates deteriorate first, causing the arrester leakage current and power loss to increase.
As the grid voltage is constant, the burden on the rest of the normal valves in the surge arrester increases, resulting in an accelerated aging rate. In this way, a vicious circle is formed, which eventually leads to internal breakdown of the lightning arrester and single-phase grounding or arrester body explosion.
Another cause of accelerated aging of the zinc oxide surge arrester is the low operating voltage of the arrester. This will cause the operation of the process, especially when the system occurs single-phase grounding, will greatly increase the arrester load, resulting in rapid aging of the valve.
Precautionary measures: In addition to asking the manufacturer to improve the production process and improve the uniformity of the valve plate, the arrester should be equipped with a surge arrester with sufficient rated voltage and continuous operating voltage.
In addition, during inspections, not only the appearance of the arrester should be checked for broken flashovers, but also the value of the leakage current of the arrester should be copied and compared with the initial value. If the value is too large, the defect should be promptly reported and treated. .
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