110kV Porcelain housed Surge Arrester

Product introduction：

• Surge arrester is also called overvoltage protector. It is connected in parallel with the protected electrical equipment. It can limit various overvoltage on electrical equipment, such as lightning overvoltage, operating overvoltage, etc., so as to protect the high voltage electrical from the damage of overvoltage.

• Metaloxide varistor is used as the core component of surge arrester. The conductive mechanism of MOV is based on the non-linear volt-ampere characteristics of Schottky barrier model. The arrester is based on the principle of the non-linear volt-ampere characteristic of metal oxide varistor, which makes the arrester hold high resistance under the normal operating voltage of power system, which is equivalent to an insulator, and will not interfere with the normal operation of power system. When the overvoltage of power system endangers the safe operation of the system, the varistor triggers instantaneously and presents a low resistance. Forming a channel to release overvoltage energy, and clamp system voltage within the allowable range of the system to ensure the safe operation of the power system.

• The arrester is porcelain-housed surge arrester. It has the advantages of high current impulse withstand capacity, large protection capacity and strong pollution resistance.

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 What are the structural characteristics of the porcelain shell arrester?

Porcelain Housing

The porcelain housing is a critical external structural component, offering excellent insulation properties and mechanical strength. The porcelain material can withstand electric field intensities of up to 110kV, preventing flashovers between internal components and the external environment. Additionally, the porcelain housing can endure certain mechanical stresses, such as wind and vibrations, protecting the sensitive internal components. Typically cylindrical in shape with a smooth surface, the porcelain housing helps reduce the adhesion of dust and contaminants. During manufacturing, it undergoes rigorous quality inspections to ensure there are no cracks or defects that could compromise its insulating properties.

Internal Components

The core internal component is the zinc oxide varistor disc. Under normal operating voltage, the zinc oxide varistor disc exhibits a high-resistance state, allowing only minimal current to pass through. When overvoltage occurs, its resistance drops sharply, forming a low-resistance path that allows the overvoltage-induced current to pass smoothly. These discs are made primarily from zinc oxide using specialized manufacturing processes, resulting in nonlinear volt-ampere characteristics that effectively limit the amplitude of overvoltages. Additionally, the internal structure may include connecting elements to link the varistor discs appropriately and auxiliary components like grading rings to ensure uniform voltage distribution across the discs during high-voltage conditions.

Sealing and Connection Structure

The porcelain-housed surge arrester features a robust sealing structure to prevent moisture, dust, and harmful gases from entering and affecting the performance of internal components. At both ends, there are connection structures for integrating the arrester into 110kV power lines. These connection parts are typically made of metal, capable of withstanding high voltages and large currents while providing excellent conductivity. This ensures that during an overvoltage event, current can flow smoothly into and out of the arrester.