10kv zinc oxide arrester is an arrester with good protection performance. The good nonlinear volt-ampere characteristics of zinc oxide are used to make the current flowing through the arrester at normal operating voltage extremely small (microamperes or milliamperes); when overvoltage occurs, the resistance drops sharply and the energy of the overvoltage is discharged to achieve the protection effect. The difference between this kind of arrester and traditional arrester is that it has no discharge gap and uses the nonlinear characteristics of zinc oxide to play the role of discharge and breaking.
Zinc oxide arrester is a new type of arrester developed in the 1970s. It is mainly composed of zinc oxide varistor. Each varistor has a certain switching voltage (called varistor voltage) when it is made. Under normal operating voltage (that is, less than the varistor voltage), the varistor has a large value, which is equivalent to an insulation state. However, under the action of an impulse voltage (greater than the varistor voltage), the varistor has a low value and is broken down, which is equivalent to a short-circuit state. However, after the varistor is struck, it can return to the insulation state; when the voltage higher than the varistor voltage is removed, it returns to the high resistance state. Therefore, if a zinc oxide arrester is installed on a power line, when a lightning strikes, the high voltage of the lightning wave causes the varistor to break down, and the lightning current flows into the earth through the varistor, which can control the voltage on the power line within a safe range, thus protecting the safety of electrical equipment.
characteristic
Seven characteristics of 10kv zinc oxide arrester:
Flow capacity
This is mainly reflected in the arrester's ability to absorb various lightning overvoltages, power frequency transient overvoltages, and operating overvoltages.
Protection characteristics
Zinc oxide arresters are electrical products used to protect various electrical equipment in the power system from overvoltage damage and have good protection performance. Because the nonlinear volt-ampere characteristics of the zinc oxide valve are very good, only a few hundred microamps of current can pass through it under normal operating voltage, making it easy to design into a gapless structure, making it feature good protection performance, light weight, and small size. When overvoltage invades, the current flowing through the valve plate increases rapidly, which limits the amplitude of the overvoltage and releases the energy of the overvoltage. After that, the zinc oxide valve plate returns to the high resistance state, allowing the power system to operate normally.
10kv zinc oxide arrester, 35kv zinc oxide arrester manufacturer
Sealing performance
The arrester components adopt high-quality composite jackets with good aging performance and good air tightness. Measures such as controlling the compression amount of the sealing ring and adding sealant are adopted. The ceramic jacket is used as a sealing material to ensure reliable sealing and stable performance of the arrester. [4]
Mechanical properties
The following three factors are mainly considered: the earthquake force withstood; the maximum wind pressure acting on the arrester; and the maximum allowable pulling force of the conductor that the top of the arrester bears.
Decontamination performance
Gapless zinc oxide arresters have high pollution resistance.
The creepage distance levels stipulated in the national standards are: Level II moderately polluted areas: creepage distance 20mm/kv; Level III heavily polluted areas: creepage distance 25mm/kv; Level IV extremely polluted areas: creepage distance 31mm/kv.
High operational reliability
The reliability of long-term operation depends on the quality of the product and whether the product selection is reasonable. There are three main aspects that affect its product quality: the rationality of the overall structure of the arrester; the volt-ampere characteristics and aging resistance of the zinc oxide valve plate; and the sealing performance of the arrester.
Power frequency withstand capability
Due to various reasons in the power system, such as single-phase grounding, long-line capacitance effect, and load shedding, the power frequency voltage will increase or a transient overvoltage with a high amplitude will occur. The arrester has the ability to withstand a certain power frequency voltage increase within a certain period of time.
effect
Each type of lightning arrester has its own advantages and characteristics, and needs to be used in different environments to achieve good insulation effects. Under rated voltage, the arrester is equivalent to an insulator and will not cause any action. When a crisis or high voltage occurs, the lightning arrester will take effect and guide the current into the earth, effectively protecting the power equipment.
Classification
According to voltage level
Zinc oxide arresters are classified according to their rated voltage values and can be divided into three categories:
High voltage category: It refers to a series of zinc oxide arresters of levels above 66KV, which can be roughly divided into seven levels: 1000kV, 750kV, 500kV, 330kV, 220kV, 110kV, and 66kV.
Medium voltage category: It refers to the zinc oxide arrester series products in the range of 3kV ~ 66kV (excluding 66kV series products), which can be roughly divided into four voltage levels: 3kV, 6kV, 10kV, and 35KV.
Low voltage category: It refers to zinc oxide arrester series products below 3KV (excluding 3kV series products), which can be roughly divided into four voltage levels: 1kV, 0.5kV, 0.38kV, and 0.22kV.
According to nominal discharge current
Zinc oxide arresters can be divided into five categories according to their nominal discharge current: 20, 10, 5, 2.5, and 1.5kA.
According to use
Zinc oxide arresters can be divided into seven categories according to their uses: system line type, system power station type, system distribution type, parallel compensation capacitor bank protection type, electrified railway type, motor and motor neutral point type, and transformer neutral point type.
According to structure
Zinc oxide arresters can be divided into two major categories according to their structure.
Porcelain jacket: Porcelain jacket zinc oxide arresters are divided into four levels according to their pollution resistance. Level I is for ordinary types, Level II is for use in moderately polluted areas (specific creepage distance 20mm/KV), Level III is for use in heavily polluted areas (specific creepage distance is 25mm/kV), and Level IV is for use in extremely polluted areas (specific creepage distance is 31mm/kV).
Composite jacket: The composite jacket zinc oxide arrester is made of composite silicone rubber material and high-performance zinc oxide resistor. The interior adopts a special structure and is assembled using advanced technology. It has the dual advantages of silicone rubber material and zinc oxide resistor. In addition to all the advantages of porcelain-coated zinc oxide arresters, this series of products also has the advantages of good insulation performance, high pollution resistance, good explosion-proof performance, small size, light weight, no maintenance required, not easy to be damaged, reliable sealing, and excellent aging resistance.
According to structural performance
Zinc oxide arresters can be divided into three categories according to structural performance: no gap (W), with series gap (C), and with parallel gap (B).
