Siemens Energy 3EK8 Wrap Design

The 3EK8 is a silicone rubber surge arresters with wrap design effectively protect medium-voltage distribution networks from overvoltage.

Siemens Energy 3EK8 wrap design surge arresters are ideally suited to provide reliable protection for:

• Transformers

• Circuit breakers

• Medium-voltage switchgear

• Medium-voltage distribution networks

The silicone rubber housing is directly molded onto the metal oxide (MO) blocks. This creates a reliable seal that prevents moisture ingress and partial discharges.

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Siemens Energy 3EK7 Cage Design

The 3EK7 Silicone rubber surge arresters with cage design effectively protect medium-voltage distribution networks from overvoltage.

They are ideally suited to provide reliable protection for:

• Transformers

• Circuit breakers

• Medium-voltage switchgear

• Medium-voltage distribution networks

The cage, made of fiberglass-reinforced plastic (FRP) rods, provides a rigid, reinforced structure ensuring high mechanical strength.

 

The silicone rubber housing is directly molded onto the metal oxide (MO) blocks and the surrounding cage made of FRP rods. This creates a reliable seal that prevents moisture ingress and partial discharges.

The MO resistors are not surrounded by a rigid mechanical coating, which is why no critical increases in pressure can occur in the surge arrester in the extremely rare event of an overload. The arc can escape directly through the soft silicone housing without damaging the mechanical structure. No internal parts are ejected in the process. The innovative Siemens cage design is very secure.

The silicone rubber is highly hydrophobic. This keeps any conductive moisture from forming on the surface, and dirt deposits are rendered harmless as a result of the hydrophobic transfer. Silicone is highly fire-retardant and self-extinguishing in the event of fire. These properties ensure the reliable, maintenance-free operation of 3EK surge arresters.

Siemens Energy offers 3EK7 surge arresters for use in distribution networks for rated voltages up to 60 kV with very high mechanical strength.

 

The proven type 3EK7 surge arrester is also available for indoor use. The 3EK7 surge arrester for indoor use is a cage design surge arrester that offers the same features as the version for outdoor use.

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Siemens Energy 3EH4 plug-in surge arresters
The 3EH4 medium-voltage plug-in surge arrester optimally protects your transformers and switchgear against overvoltages and lightning. Thanks to the alignment of the arrester's protection performance with the impulse withstand voltage of encapsulated switchgear and transformers, overvoltages generated by the reflection of traveling waves and switching operations are also limited.

Rugged design for high power and a long life
 

The plug-and-socket connection is available in connector sizes 2 and 3 and is dimensioned to EN 50180 / EN50181 for the inner cone system. The 3EH4 medium-voltage surge arrester corresponds to arrester class DH and is suitable for operating voltages up to 52.5 kV. Low residual voltages guarantee superior insulation coordination and protection.

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Siemens Energy 3EQ surge arresters, silicone housing and hollow core design 

The Siemens Energy 3EQ0 surge arresters are for rated voltages of up to 45 kV for applications in which a surge arrester in silicone housing is required in combination with directional pressure relief.

The surge arrester with the composite hollow core design uses silicone and fiberglass-reinforced plastic (FRP) as housing materials. The direct molding of the silicone onto the FRP hollow core ensures reliability, while an excellent special sealing of the flanges at both ends of the surge arrester effectively prevents partial discharges and moisture ingress. This guarantees decades of trouble-free operation.

The combination of silicone rubber and the fiberglass-reinforced hollow core also allows for outstanding mechanical stability.

The surge arrester with the composite hollow core design provides a very high degree of safety: In the event of an overload or the extremely rare case of an arrester short circuit, the arc escapes directly through directional pressure relief devices.

The surge arrester can be oriented to minimize the risk of damage to facilities and injuries to people nearby. Internal parts are not ejected, and the housing does not break.
 

Siemens Energy 3EQ surge arresters with silicone housing and a composite hollow core design are ideally suited for the reliable protection of:

-         Generators

-         Motors

-         Arc furnaces

-         Dry-type transformers

-         Airfield lighting systems

-         Cable sheathing

-         Capacitors and capacitor banks

-         Converters for drives

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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.

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

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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

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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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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:

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• 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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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.

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

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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.

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.

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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.​

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Non-Gapped Line Arresters (NGLA)
NGLAs connect directly to overhead lines and offer maximum installation flexibility, whether mounted on towers, insulators, or conductors. These arresters effectively limit overvoltages to safe levels below the insulator’s withstand voltage.

Key Features:

• Flexible installation on conductors, towers, or insulators

• High energy absorption ensures superior protection against overvoltages

• Built-in disconnector isolates the arrester in case of thermal overload, ensuring continued line operation until replacement

• Fully compliant with IEC 60099-4 standards

 

Externally Gapped Line Arresters (EGLA)
EGLAs feature an external spark gap that isolates the arrester from the high-voltage line under normal conditions. Upon lightning strikes, the spark gap activates to limit fault current, extinguishing arcs within 10 ms without triggering circuit breaker operations or reclosing events.

Key Features:

• No leakage current during normal operation due to the series gap

• Lower rated voltage requirements, reducing material costs

• No need for a disconnector or ground lead

• Compact design enables installation on towers with limited clearance

• Ideal for live installations

• Available with polymer insulators

• Fully compliant with IEC 60099-8 standards

 

Software-Driven Solutions for Custom Applications
Toghter with Simens Energy we provide advanced software simulations based on Cigré methodologies to determine optimal LSA configurations for specific projects. This approach ensures cost-efficient solutions by enabling targeted installation of LSAs on critical phases or line segments, while still ensuring effective lightning protection.

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Simulation Parameters Considered:

• Line parameters: Voltage, conductor type, span length, and sag

• Tower data: Surge impedances, footing resistance, and geometry

• Insulator properties: Arcing distance, connection length, and LIWL ratings

• Environmental factors: Lightning activity and network topology

• Customer priorities: Minimising interruptions and preventing multi-system short circuits

 

With Siemens' LSAs, MV Technology Solutions provides reliable overvoltage protection, enhancing the resilience and performance of transmission systems while reducing operational costs