+8615829333876
+8615829333876
Seven characteristics of zinc oxide arrester:
1. Flow capacity
This is mainly reflected in the arrester has the ability to absorb all kinds of lightning overvoltage, power frequency transient overvoltage, operation overvoltage.
2. Protection features
Zinc oxide arrester is used to protect all kinds of electrical equipment in power system from overvoltage damage of electrical products, with good protection performance. Because the nonlinear volt-ampometric characteristics of the zinc oxide valve are very good, only a few hundred microamps of current pass through the normal working voltage, it is easy to design a gap-free structure, so that it has the characteristics of good protection performance, light weight and small size. When the overvoltage invades, the current flowing through the valve disc increases rapidly, and at the same time limits the amplitude of the overvoltage and releases the energy of the overvoltage. After that, the zinc oxide valve disc returns to the state of high resistance, so that the power system works normally.
3. Sealing performance
The element of the arrester adopts the high quality composite coat with good aging performance and good air tightness, and adopts the measures of controlling the compression amount of the sealing ring and increasing the sealant. The ceramic coat is used as the sealing material to ensure the reliable sealing and the stable performance of the arrester.
4. Mechanical properties
The following three factors are mainly considered: the seismic force borne; Maximum wind pressure acting on the arrester; The top of the arrester bears the maximum allowable tension of the wire.
5. Anti-fouling performance
No gap zinc oxide arrester has high fouling resistance.
The creepage distance grade stipulated by the national standard is: II moderately polluted area: creepage distance 20mm/kv; Class III heavily polluted area: creepage ratio 25mm/kv; Class IV particularly polluted areas: creepage specific distance 31mm/kv.
6. High operational reliability
The reliability of long-term operation depends on the quality of the product and whether the selection of the product is reasonable. Affect its product quality mainly has the following three aspects: the rationality of the overall structure of the arrester; The voltammetry characteristics and aging resistance of zinc oxide valve; The sealing performance of the arrester.
7. Power frequency tolerance
Due to the power system such as single-phase grounding, long line capacitance effect and load rejection and other reasons, will cause the rise of power frequency voltage or produce a high amplitude transient overvoltage, the arrester has a certain time to withstand a certain power frequency voltage rise ability.
Zinc oxide arrester is a new type of arrester developed in the 1970s, which is mainly composed of zinc oxide varistor. Each piece of varistor from the time it is made has its certain switching voltage (called varistor voltage), in the normal working voltage (that is, less than the varistor voltage) varistor value is very large, equivalent to the insulation state, but under the action of impact voltage (greater than the varistor voltage), varistor is low value is broken down, equivalent to the short-circuit state. However, after the varistor is struck, it can restore the insulation state; When the voltage higher than the varistor voltage is withdrawn, it returns to the high resistance state. Therefore, if the zinc oxide arrester is installed on the power line, when lightning strikes, the high voltage of the lightning wave makes the varistor break down, and the lightning flow over the varistor flows into the earth, which can control the voltage on the power line within the safe range, thus protecting the safety of electrical equipment.
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