Created by: Glen Zhu | Updated Date: March 27th, 2025
In the power system, surges and lightning strikes may cause serious damage to equipment and buildings, so choosing the appropriate protective devices is crucial. However, many people often confuse surge arresters and lightning arresters. Improper use in critical scenarios can lead to system failure, equipment damage, or even safety accidents. This article will help you fully understand the differences between these two devices in order to make a more informed decision.
A surge arrester (Surge Arrester) is a protective device used to prevent transient voltage surges from damaging electrical equipment. It can detect abnormal voltage peaks in the system and quickly divert excess energy to the ground, thereby preventing voltage surges from causing damage to sensitive equipment.
The main function of the surge arrester is to suppress and guide transient overvoltages, usually composed of core components such as metal oxide varistors (MOV) or gas discharge tubes (GDT). The following is the working mechanism of the surge arrester:
A lightning arrester is a device used to protect buildings, power systems, and equipment from direct lightning strikes and induced lightning damage. By directing the lightning current directly to the ground, the lightning arrester effectively prevents high-voltage lightning strikes from causing serious damage to equipment or buildings, thus becoming the first line of defense against lightning strikes.
The core function of a lightning arrester is to safely divert the flow of electricity into the ground, preventing the intrusion of electrical energy into electrical equipment or building interiors and reducing damage caused by thunderstorms. Therefore, a Lightning Rod plays an active role in thunderstorm protection by actively guiding thunderstorms. Its working principle is as follows:
No, a surge arrester and a lightning arrester are not the same.
Lightning Arrester
Surge arrester: Specifically used to suppress surge voltages generated internally in the system (such as transient overvoltages caused by power grid fluctuations, load switching, equipment startup, etc.), by directing excess current to the ground to prevent damage to electrical equipment.
Lightning arrester: Mainly used for diverting lightning strikes, preventing the huge energy impact caused when lightning directly hits buildings or power systems. The lightning arrester provides a low impedance path to divert the lightning current into the ground, thereby avoiding equipment and structural damage.
Surge arrester: usually installed internally in the power system, such as distribution boards, terminal equipment, photovoltaic combiner boxes, etc., to provide protection for the equipment. Surge arresters are generally installed at the power inlet of the system or at the front end of equipment to mainly prevent voltage surges within the system.
Lightning arrester: typically installed externally in the system, especially on building roofs, communication base station antennas, external transmission lines, etc., to prevent external lightning strikes from causing harm to the system. The installation position of lightning arresters ensures that they can preferentially guide lightning currents into the ground.
Surge arrester: designed to withstand and dissipate low to moderate intensity voltage surges, typically transient voltages ranging from several kilovolts to tens of kilovolts. Its goal is to protect equipment from overvoltages generated by grid disturbances, equipment switches or load switching.
Lightning arrester: able to withstand extremely high voltages and currents, generally designed for strong voltages and currents caused by lightning strikes, with voltages typically reaching hundreds of kilovolts or higher. Its main task is to protect buildings, power systems and equipment from the effects of lightning direct current.
Surge arrester: response speed is usually fast enough to suppress surge voltages from within the system instantaneously; response time is generally on a nanosecond level. Its main function is handling transient and frequently occurring voltage surges.
Lightning arrester: also has very fast response speed; it can quickly guide current into the ground during a lightning strike moment; response time is also on a nanosecond level. Due to powerful energy released during a lightning strike event ,the arrester needs quick reaction times in order to prevent damage to both devices and buildings.
Below we will differentiate between SPD and lightning arrester through a table.
Characteristic | Surge Arrester | Lightning Arrester |
Primary Objective | Suppress internal transient surges | Divert external lightning currents to ground |
Operating Principle | Limit surge voltage to safe levels | Rapidly channel lightning currents to the ground |
Typical Voltage Range | 1.5kV – 20kV | 100kV – 1000kV |
Typical Surge Current | 10kA – 100kA (8/20μs) | 100kA – 200kA (10/350μs) |
Response Time | Nanosecond range (5ns – 25ns) | Microsecond range (10ns – 100ns) |
Surge/Lightning Energy Level | Moderate surge energy | Extremely high lightning energy |
Applicable Voltage Systems | 230V, 400V, 1000V, etc. (low voltage systems) | 3kV – 500kV (high-voltage transmission systems) |
Typical Installation Locations | Distribution panels, equipment front-end, terminal equipment entry | Building rooftops, transmission line entry points, junction box entrances |
Typical Applications | Data centers, photovoltaic systems, communication lines | Substations, communication base stations, wind farms |
Service Life | Frequent surges may cause component aging | Longer service life, influenced by the number of lightning strikes |
Table 1 – Difference Between Surge Arrester and Lightning Arrester
To provide comprehensive electrical protection for the system, it is necessary to consider system requirements, potential risks, and environmental conditions comprehensively and make wise equipment choices.
Forming a multi-level protection barrier through the combination of “lightning arrester + surge arrester”.
Choosing the appropriate protective equipment is an important step in ensuring the safety of electrical systems. Depending on different system requirements and usage scenarios, choosing surge arresters or lightning rods reasonably can effectively prevent equipment damage and system failures.
1. Use of surge arresters:
2. Use of lightning arrester:
When choosing protective equipment, many people have misunderstandings about the functions and uses of surge arresters and lightning arresters. Incorrect understanding may result in ineffective protection of the system, or even serious consequences. Here are two common misconceptions about surge arresters and lightning arresters, as well as the potential risks that these misunderstandings may bring.
Misconception: Many people believe that surge arresters and lightning arresters have similar functions and can be used interchangeably.
Truth: The working mechanism and application scenarios of the two are completely different, so they cannot be substituted for each other.
Key differences:
Misconception: In some scenarios, using only surge arresters or lightning arresters can fully protect the power system without needing both.
Truth: If the wrong equipment is used in critical situations, it may result in serious system failures, equipment damage, and even catastrophic consequences.
Potential risks include:
Correct approach:
LSP’s reliable surge protection devices (SPDs) are designed to meet the protection needs of installations against lightning and surges. Contact our Experts!
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