Overview
Zinc oxide arrester is an arrester with good protection performance. The good nonlinear volt ampere characteristics of zinc oxide make the current flowing through the arrester very small (micro ampere or milliampere level) under normal working voltage; When over-voltage acts, the resistance drops sharply, and the over-voltage energy is released to achieve the protection effect. The difference between this arrester and the traditional arrester is that it has no discharge gap and takes advantage of the nonlinear characteristics of zinc oxide to discharge current and disconnect.
Seven characteristics of zinc oxide arrester
Flow capacity
This is mainly reflected in the lightning arrester’s ability to absorb various lightning overvoltage, power frequency transient overvoltage and switching overvoltage.
Protection characteristics
Zinc oxide arrester is an electrical product used to protect various electrical equipment in the power system from overvoltage damage, with good protection performance. Because of the excellent non-linear volt ampere characteristics of zinc oxide valve slice, only a few hundred microamps of current can pass through under the normal working voltage, which is convenient to design a gapless structure, making it have the characteristics of good protection performance, light weight and small size. When overvoltage intrudes, the current flowing through the valve plate increases rapidly, at the same time, the amplitude of the overvoltage is limited, and the overvoltage energy is released. After that, the zinc oxide valve plate returns to the high resistance state, making the power system work normally.
Sealing performance
High quality composite jacket with good aging performance and air tightness is used for arrester elements. Measures such as controlling the compression amount of sealing ring and adding sealant are adopted. Ceramic jacket is used as sealing material to ensure reliable sealing and stable performance of arrester.
Mechanical properties
The following three factors are mainly considered: earthquake force; The maximum wind pressure acting on the arrester; The top of the arrester bears the maximum allowable tension of the conductor.
Decontamination performance
The gapless zinc oxide arrester has high pollution resistance.
The specific creepage distance specified in the national standard is: Grade II, medium pollution area: the specific creepage distance is 20mm/kv; Grade III heavily polluted area: creepage distance 25mm/kv; Grade IV extremely polluted area: specific creepage distance is 31mm/kv.
High operation reliability
The reliability of long-term operation depends on the quality of products and the rationality of product selection. The quality of its products is mainly affected by the following three aspects: the rationality of the overall structure of the arrester; Volt ampere characteristics and aging resistance of zinc oxide valve plate; Sealing performance of arrester.
Power frequency tolerance
Due to various reasons in the power system, such as single-phase grounding, long line capacitance effect and load rejection, the power frequency voltage will rise or the transient over-voltage with high amplitude will occur. The arrester has the ability to withstand a certain power frequency voltage rise within a certain period of time.
Conditions Of Use
- Ambient temperature: -40°C~+40°C
-Maximum wind speed: no more than 35m/s
-Altitude: up to 2000 meters
- Earthquake intensity: no more than 8 degrees
- Ice thickness: not more than 10 meters.
- The long-term applied voltage does not exceed the maximum continuous working voltage.
