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Surge Arresters for medium voltage and high voltage systems


Surge Arresters

Surge arresters for medium voltage and high voltage systems

  • IEC line discharge, class 1- 4

  • Polymeric and porcelain constructions

  • Voltages 3KV – 420KV

  • ZnO technology



Surge arresters are widely used in distribution and transmission networks to ensure the protection of assets against overvoltages resulting from switching in the network or from lightning strikes on the line.


Surge arresters are often a sacrificial device which protects the considerably more expensive transformers or reclosers, in addition to substation assets.


The higher the Line Discharge Class of the arrester, the higher it's energy capability. This means a high-class arrester would have lower residual voltages in the event of a lightning strike, and would be capable of enduring a higher energy lightning strike. Of course, the cost of a higher class arrester is much higher.


Arresters are always installed close to the device they are protecting, connected with a lead which is as short as possible. Arresters are mounted on pole top transformers, usually on the tank with a cable connection to the bushing. In distribution networks up to 33KV the most common arresters are IEC Line Discharge Class 1 arresters, also commonly known as distribution arresters, due to their low-cost position. A significant number of them are used on distribution transformers in order to keep down costs. The lower energy, lower class arrester is often a sacrificial device, destroyed whilst protecting the asset in the event of a  lightning strike. In such an event, the arrester must be replaced.


All arresters currently use Zinc Oxide blocks in their construction and as the active element of the arrester. Today's arresters are gapless, meaning there is no air gap within the construction. This is made possible by the unique property of ZnO, which has extremely high resistance at zero voltage. With higher voltages the ZnO drastically drops its resistance, allowing current to flow through it.


There are many different types of arresters ranging from AC or DC, for use in railway networks, generators, etc, and may differ greatly in construction, voltage range, mechanical properties, etc.  Each design is adapted to its particular application.


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High-voltage station arresters

Protect devices in equipment for applications up to 1,200 kV.   

Our extensive portfolio offers several versions of high-voltage station arresters for every conceivable application - even specific demands. These surge arresters can provide protection for devices in equipment for applications up to 1,200 kV.

There are a three types of high-voltage station surge arresters within our portfolio.

3EL product family – Surge arresters with directly molded silicone rubber housing, Cage Design™

3EQ product family – Surge arresters with silicone housing, composite hollow core design

3EP product family – Surge arresters with porcelain housing

Main Features:

  • High mechanical stability for support applications and for use in regions with high seismic activity

  • Extremely reliable pressure relief for use in areas requiring special protection

  • Excellent pollution layer characteristics for use in coastal and desert regions or in areas with extreme air pollution

  • All three surge arrester product families feature a superior sealing system that reliably prevents moisture ingress

  • Decades of trouble-free service

  • Manufactured using only environmentally compatible materials

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Medium-voltage arresters for distribution networks

Protection for medium-voltage distribution networks up to 72.5 kV.

Our portfolio contains surge arresters design for medium-voltage applications. These provide reliable overvoltage protection for medium-voltage distribution networks and components for applications up to 72.5 kV.

There is a wide range of medium-voltage arresters available for different applications:

Surge Arresters for Distribution Networks.

Siemens Energy 3EK distribution class arresters are ideally suited for the reliable protection of transformers, circuit breakers, medium-voltage switchgear and distribution lines.

Surge Arresters with High Energy absorption capabilities

In addition to typical distribution class surge arresters, also offered is the 3EJ surge arrester product family with higher energy absorption capabilities in combination with a low protection level. The 3EJ medium-voltage surge arresters protect generators, motors, arc furnaces, dry-type transformers, airfield lighting systems, cable sheathing and converters for drives from overvoltage.

Plug-in surge arresters

The 3EH4 medium-voltage plug-in arresters optimally protect your transformers and switchgear against switching overvoltages and lightning.

Special applications

The 3EQ0 product series for applications that require a surge arrester with a silicone rubber housing and directional pressure relief.

Also offered is the 3EP-G porcelain housed surge arresters with short-circuit current capability up to 300 kA for the overvoltage protection of generators and motors

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Monitoring devices for early fault detection and security of supply.

Senarresters™ offer added transparency, enhanced productivity and advanced intelligence. Through it, all main electrical functionalities of a surge arrester are now connective, allowing you to check the surge arrester's status via online applications - in real time. Paired with data analytics, they increase the efficiency and the sustainability of your assets and operations.


Senarresters™ will provide real-time remote access to surge arrester monitoring data, as well as:

  • Wireless cloud access to recorded data via app (IOS & Android) or web browser.

  • World map view of all Siemens Energy Sensproducts™ within one app (transformers, GIS, circuit breakers, instrument transformers, surge arresters)

  • Dashboard with latest surge arrester values within each substation at a glance:

    • Leakage currents​

    • Surge counts

    • Logbook of last events

    • Ambient temperature and weather data

    • Total time of operation

  • Trend curve analysis over complete lifetime with warning levels

  • Historical data within a chosen time period

  • Event log showing leakage current curve and weather condition at surge event

  • Alert function for critical surge arrester conditions via Email or push notification

  • Maintenance-free for lifetime, automated firmware updates via cloud solution.

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Surge Counters

Monitoring devices for early fault detection and security of supply.

The 3EX5 030 surge counter is a traditional monitor for surge arresters. It is integrated into the arrester ground connection and counts the surge arrester responses that have occurred.

The 3EX5 050 surge counter with leakage current meter also monitors and displays the arrester leakage current.

In addition to the functions described here, versions 3EX5 030-1 and 3EX5 050-1 can also be equipped with a passive auxiliary contact for remote metering.

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Line surge arresters

Prevent ground faults and short circuits in power lines.

Line Surge Arresters (LSA) are designed to prevent ground faults and short circuits in power lines caused by lightning or switching overvoltages. Insulator flashovers, voltage dips and interruptions are prevented by eliminating all lighting and switching overvoltages above the insulator insulation level (the lightning-impulse withstand level, LIWL for short).

The installation of line surge arresters at recommend locations, in accordance with our line simulation, ensures enhanced overvoltage protection. Selecting optimum line surge arresters - in terms of quantity and installation locations - significantly improves the reliability of the overall line system and the quality of power that it suppliers.

We offer line surge arresters for system voltages up to 800kV and an energy discharge capability of 3.6 C.

There are numerous benefits of line surge arresters:

  • Improve lightning protection performance

  • Reduce outages caused by poor grounding and high lightning activity

  • Reduce double-circuit outage rates / protect underbuild distribution lines

  • Provide switching surge control - structural optimization and lower clearances

  • Improve safety - prevents personal injuries and damage to equipment

  • For line upgrading and compaction - reduced insulation levels

  • For live work on the line - temporarily reduce minimum approach distance

  • Achieve lower installation costs and losses in line system (outages)

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Surge arresters for railway applications

Surge Arresters to protect every part of the rail system

Our surge arresters for railway applications protect every part of a rail system, from traction substations, transmission lines, cables and catenary systems to rail vehicles for local, long distance and high-speed services up to 420 km/h.


We offer several surge arresters for AC and DC railway applications up to 45 kV:


3EB4 - Silicone rubber surge arresters with composite hollow core design for use on traction vehicles and for fixed installation in AC and DC systems.


3EB5  - Silicone rubber surge arresters with Cage Design™ for use on traction vehicles and for fixed installation in AC and DC systems.

3EB2 and 3EB3 - Surge arresters with silicone rubber housing for use on traction vehicles and for fixed installation in DC systems; A1 and A2 application. The 3EB2 is DC-B classified, the 3EB3 is DC-C classified.