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What are the characteristics of zinc oxide arrester?
Zinc Oxide Arrester is a new arrester developed in the 1970s. It is mainly composed of zinc oxide varistors. Each varistor has a certain switching voltage (called varistor voltage) when it is manufactured. Under normal operating voltage (ie, less than varistor voltage), the varistor has a large value, which is equivalent to the insulation state, but Under the impact voltage (larger than the varistor voltage), the varistor is punctured at a low value, which is equivalent to a short-circuit condition.
However, after the varistor is struck, it is possible to restore the insulation state; when the voltage above the varistor voltage is removed, it returns to the high-impedance state. Therefore, if a zinc oxide surge arrester is installed on the power line, when a lightning strikes, the high voltage of the lightning wave breaks down the varistor, and the lightning current flows into the earth through the varistor, so that the voltage on the power line can be controlled within a safe range. This protects the safety of electrical equipment.
1, zinc oxide arrester flow capacity
This is mainly reflected in the lightning arrester has the ability to absorb various lightning over-voltage, transient over-voltage industrial frequency, operating over voltage. The flow capacity produced by Tuopu Electric fully meets or exceeds the requirements of the national standard. Line discharge level, energy absorption capacity, high current tolerance of 4/10 nanoseconds, 2ms square wave flow capability and other indicators have reached the domestic leading level.
2. Excellent protection characteristics of zinc oxide surge arresters
Zinc Oxide Arrester is an electrical product that is used to protect various electrical equipment in the power system from overvoltage damage and has good protection performance. Because the non-linear volt-ampere characteristic of the zinc oxide valve sheet is very good, only a few hundred microamperes of current are passed under the normal working voltage, which is easy to design into a gapless structure, so that it has good protection performance, light weight, and small size. feature.
When the over-voltage invades, the current flowing through the hair piece rapidly increases. At the same time, the magnitude of the over-voltage is treated first, and the over-voltage energy is released. Then, the zinc oxide valve piece resumes the high-impedance state and the power system works normally.
3, zinc oxide arrester sealing is good
Arrester components have good aging properties. High-quality composite jacket with good airtightness uses measures such as controlling the compression amount of the seal ring and the sealant for increasing the figure. The ceramic jacket acts as a sealing material to ensure reliable sealing and is a stable performance of the arrester.
4, the mechanical properties of zinc oxide surge arresters
The following three factors are mainly considered: 1) the seismic force to be subjected to; 2) the maximum wind pressure acting on the lightning arrester: 3) The top of the arrester is subjected to the maximum allowable tension of the wire.
5, zinc oxide arrester good decontamination performance
The gapless zinc oxide surge arresters have high dirt resistance. Current national standards for creepage distances are: Class II secondary pollution areas: creepage distance 20mm/kv; Class III heavy pollution areas: creepage distance 25mm/kv; IV Special heavy pollution areas: creepage ratio 31mm/kv away
6. High operating reliability of zinc oxide surge arresters
The reliability of long-term operation depends on the quality of the product and whether the selection of the product is reasonable. The quality of the products affecting it mainly includes the following three aspects: 1) The rationality of the overall structure of the arrester; 2) The volt-ampere characteristic and the anti-aging property of the zinc oxide valve; 3) The sealing performance of the arrester.
7. Power frequency withstand capability of zinc oxide surge arresters
Due to various reasons such as single-phase grounding, long-line capacitance effect, and load, the power system may cause the increase of the power frequency voltage or the generation of a transient overvoltage with a high amplitude. The arrester can withstand certain power frequency voltage for a certain period of time. Increase capacity.