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Detection Technology

Fault detection of zinc oxide arrester

time:2020/12/17   source:华天电力  reading:540 time

Most power stations use lightning arresters for lightning protection measures, among which the most commonly used is zinc oxide arresters. However, any equipment has the risk of failure.

Common failures are mainly caused by poor sealing,

Cause analysis: Poor sealing of zinc oxide arrester is mainly caused by the production process of the product. For example, the zinc oxide arrester valve is not completely dried, contains moisture, or the sealing gasket of the arrester is improperly placed or even not installed during assembly. Some manufacturers use The material is unqualified. If the quality of the porcelain bottle is poor, the invisible holes will also cause moisture to penetrate and make the interior damp.

Zinc Oxide Arrester Tester.png

Precautionary measures: In order to prevent the lightning arrester from being poorly sealed, the user should conduct a strict sealing test before using it. In addition, during the operation and maintenance of the zinc oxide arrester, especially after a thunderstorm, it is necessary to strengthen the inspection of the arrester in order to find abnormal conditions in time , When using the zinc oxide arrester tester to conduct regular preventive tests on the arrester, the tester must carefully analyze the test data, because when the arrester is damp, there may not be any appearance problems, but only through the test data can the internal defects be found .

The second reason is: internal valve aging

Reason analysis: valve aging generally occurs during operation. Due to the poor uniformity of the arrester valve, its aging degree is not the same, which will make the potential distribution of the valve plate uneven. After a period of operation, part of the valve plate first deteriorates, causing The lightning arrester leakage current and power loss increase.

As the grid voltage remains unchanged, the burden on the remaining normal valves in the zinc oxide arrester is heavier, resulting in faster aging, which forms a vicious circle, which eventually leads to internal breakdown of the zinc oxide arrester, single-phase grounding, or explosion of the arrester body .

Another reason for the accelerated aging of the zinc oxide arrester valve is that the zinc oxide arrester continues to operate at a low voltage, which will cause the operation process, especially when the system is single-phase grounded, to greatly increase the load of the zinc oxide arrester and cause rapid aging of the valve. .

Preventive measures: In view of the aging problem of the zinc oxide arrester valve, in addition to requiring manufacturers to improve the production process and improve the uniformity of the valve, it is also necessary to select an arrester with sufficient rated voltage and continuous operating voltage when designing and selecting. When patrolling, you should not only check the appearance of the arrester for damage and flashover, but also copy the leakage current value of the arrester and compare it with the initial value. If the value is too large, you should report the defect in time and deal with it.

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