Metal oxide arrester testers are widely used in power grids with voltages below 10KV. They are mainly used to prevent lightning waves from damaging electrical equipment in substations. They are a common high-voltage arrester device. 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, breakdowns and noises may occur from time to time.
Rare failures are mainly caused by the following reasons:
Poor seal
Appreciation of the reasons for the metal oxide arrester DC parameter measuring instrument: poor sealing of the arrester mainly occurs during the production process of the product. If the arrester valve plate is not completely dried, it contains moisture. Perhaps when disassembling, the sealing ring of the arrester is installed in the wrong position or even the zinc oxide arrester DC parameter measuring instrument is not installed. The materials used by some manufacturers are not decent. For example, the porcelain bottles used are of poor quality and have invisible holes that can cause moisture to penetrate and freeze the outside. Precautionary measures: In order to prevent poor sealing of high-voltage arresters, users should conduct strict sealing tests before use. In addition, during the operation and maintenance of the arrester, especially after a shower, it is necessary to strengthen the patrol of the arrester to avoid detecting abnormal conditions in time. When conducting regular preventive tests on arresters, test personnel must carefully analyze the test data. Because when the arrester is frozen, no problems may be visible on the surface, but only through test data can external defects be discovered.
External valve plate aging
Cause appreciation: Valve plate aging normally occurs during operation. Due to the poor uniformity of the arrester valve plate, its aging degree is not the same as that of the intelligent star, which will cause the valve plate flood level to be distributed unevenly. After running for a period of time, the entire valve plate will deteriorate first, causing the arrester leakage current and power consumption to increase.
Because the grid voltage remains unchanged, the burden of other ordinary valve plates in the metal oxide arrester is reduced, resulting in accelerated aging. This formed a vicious duplication, causing the arrester to produce a breakdown of the internal loop resistance test part, causing single-phase grounding or the arrester body to rattle.
Another reason for the accelerated aging of zinc oxide arrester valves is that the high-voltage arrester continues to operate at a low voltage. This will cause the arrester load to be greatly reduced during operation, especially when a single-phase grounding occurs in the system, causing rapid aging of the valve plate.
Prevention measures: For the aging problem of arrester valve plates, unless the manufacturer is required to improve the production process and improve the uniformity of the valve plates, it is also necessary to select an arrester with residual rated voltage and continuous operating voltage during design and selection. Zinc oxide lightning arrester In addition, when patrolling, not only should the surface of the arrester be checked for damage, flashover, etc., but also the leakage current value of the arrester should be taken and compared with the initial value. If the value is too large, the fault should be reported in time and addressed.
