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Lightning arrester: Lightning shield for power system, protecting the smooth flow of current

Industrial News

Lightning arrester: Lightning shield for power system, protecting the smooth flow of current

2025-01-17

In the complex and changeable natural environment, lightning is one of the major threats facing the power system. Whenever thunderstorms come, there will be strong changes in the electric field between the clouds and the ground, which will cause lightning discharge. These lightning releases huge energy instantly. If they directly hit power facilities such as transmission lines and substations, they will produce extremely high overvoltages and cause devastating damage to power equipment. The lightning arrester, like a loyal guard of the power system, shoulders a vital mission - when lightning strikes, it will promptly introduce lightning current into the earth to prevent power equipment from being hit by excessively high voltages, thereby ensuring that the power system can operate continuously and stably, allowing the current to flow smoothly in the power grid as usual, and providing uninterrupted power support for social production and life.

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1. Working principle of lightning arrester

 

Core components and characteristics

The core component of the lightning arrester is its valve plate with special nonlinear resistance characteristics. Under normal operating voltage, the valve plate presents extremely high resistance, which is almost equivalent to an insulator. At this time, the arrester has no effect on the operation of the power system, and the current can be smoothly transmitted in the power line. However, when the lightning overvoltage is generated and exceeds a certain threshold, the resistance of the valve plate will drop sharply and instantly become a good conductor. This unique nonlinear resistance characteristic enables the arrester to quickly provide a low-impedance discharge channel for the lightning current under the action of the lightning voltage, and conduct the lightning current into the earth, thereby effectively limiting the voltage rise at both ends of the power equipment and protecting it from damage.

 

The "interaction" process with lightning

When lightning strikes the power line or approaches the power facilities, it will generate a lightning overvoltage wave in the power system. The arrester can keenly sense the change of this abnormal voltage and respond quickly. The valve plate inside it starts to work, the resistance is reduced, and the lightning current flows smoothly into the earth through the arrester as if it has found a "green channel". As the lightning current is discharged, the lightning overvoltage gradually decreases. When the voltage returns to the normal operating range, the valve plate of the lightning arrester returns to the high resistance state, stops discharging current, and the power system resumes normal operation. The whole process is fast and precise, like a carefully choreographed "dance". The lightning arrester and the lightning overvoltage have a subtle and critical "interaction" to ensure that the power system is always in a safe voltage environment.

 

2. Types and characteristics of lightning arresters

 

Zinc oxide lightning arrester

Zinc oxide lightning arrester is the most widely used type of lightning arrester at present. It has many significant advantages. First, its nonlinear resistance characteristics are very excellent, and it can effectively limit overvoltage in a wide voltage range. Secondly, the current carrying capacity of zinc oxide lightning arrester is large, which means that it can withstand higher amplitude lightning current shocks without damage. In addition, the structure of this lightning arrester is relatively simple, the size is small, and it is easy to install and maintain. Whether it is in high-voltage transmission lines, substations, or various industrial and civil power facilities, it can be seen, providing a reliable and efficient solution for lightning protection of power systems.

 

Silicon carbide lightning arrester

Silicon carbide lightning arrester is a more traditional type of lightning arrester. It has played an important role in the lightning protection of power systems in the past. The main feature of silicon carbide lightning arrester is that it has certain nonlinear resistance characteristics and can limit lightning overvoltage. However, compared with zinc oxide lightning arrester, its current capacity is relatively small, and its performance may be reduced after multiple lightning current shocks. At the same time, its structure is relatively complex and its volume is large. It is gradually replaced by zinc oxide lightning arrester in some modern power engineering applications with high requirements for equipment volume and performance, but in some specific old power facilities or small power systems that are more cost-sensitive, silicon carbide lightning arrester still has a certain application.

3. Wide application of lightning arrester in power system

 

Protection on transmission lines

Transmission lines often stretch for hundreds of kilometers or even longer, crossing various terrains and climate zones, and are extremely vulnerable to lightning strikes. Installing lightning arresters on the towers of transmission lines can effectively protect the lines from lightning tripping. When lightning strikes the line, the arrester acts quickly to discharge the lightning current into the ground to prevent the line insulation from being broken down, thereby ensuring the normal transmission capacity of the transmission line and reducing power outages caused by lightning strikes, which is crucial to maintaining the stability and reliability of the power system. For example, in areas with frequent lightning activities such as mountainous areas, the installation of transmission line arresters is even more indispensable. It is like a loyal "sentry" guarding the safety of the transmission line.

 

Key role in substations

Substations are the core hubs of the power system, concentrating a large number of expensive and important power equipment, such as transformers and isolate disconnector switch. Once damaged by lightning, it will cause large-scale power outages and bring huge losses to the social economy. Lightning arresters undertake extremely critical lightning protection tasks in substations. They are distributed in various key parts of the substation, such as the incoming line, busbar, transformer, etc., forming a comprehensive lightning protection network. When lightning waves invade the substation, the arrester can shunt and discharge the lightning current in the first time, prevent the lightning overvoltage from propagating and superimposing between the equipment in the station, ensure the insulation safety of the equipment in the substation, and maintain the normal operation of the substation. It can be said that the arrester is the "mainstay" in the lightning protection system of the substation, protecting the heart of the power system.

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4. Maintenance and detection of lightning arresters

 

Key points of daily maintenance

In order to ensure that the arrester can always maintain a good working condition, daily maintenance is essential. Regularly inspect the appearance of the arrester to check whether there are abnormal conditions such as damage, dirt, and discharge marks on its surface. At the same time, check whether the connection parts of the arrester are firm, whether there are looseness, rust and other problems, to ensure that the lightning current can be smoothly discharged into the ground through the connection line. In addition, it is also necessary to pay attention to whether the arrester counter is working properly. The counter can record the number of times the arrester is actuated. By analyzing the number of actions, it can be preliminarily judged whether the arrester has experienced too much lightning current shock, so as to find potential problems in time and take corresponding measures.

 

Professional detection methods and significance

In addition to daily maintenance, regular professional detection is also essential. Common detection methods include insulation resistance test, leakage current test, etc. Insulation resistance test can check the insulation condition of the arrester and determine whether there are problems such as insulation moisture and aging. Leakage current test can monitor the leakage current size and change of the arrester under normal operating voltage. Through the analysis of leakage current, the performance change of the arrester valve plate can be understood, and whether the arrester has a performance degradation trend can be found in time. Through these professional detection methods, the health status of the arrester can be comprehensively and accurately evaluated, and hidden faults can be discovered and eliminated in advance to ensure that the arrester can reliably play its role as a lightning shield when lightning strikes, and ensure the safe and stable operation of the power system.

 

As an indispensable lightning protection device in the power system, the arrester silently guards the safety of the power system with its unique working principle, various types and wide application. Whether in the bad weather of storms or in the daily power supply guarantee, it is like a solid shield, allowing the current to flow smoothly in the power network, providing a reliable power guarantee cornerstone for the development of modern society.