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Our surge arresters for medium-voltage applications offer reliable overvoltage protection for medium-voltage distribution networks and components for applications up to 72.5 kV.
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We offer a wide range of product families for all types of requirements.
It is important to choose the surge arrester based on the application and equipment to be protected:
Surge arresters for distribution networks
Siemens 3EK distribution class surge 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, Siemens offers 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.
Siemens offers the 3EQ0 product series for applications that require a surge arrester with a silicone rubber housing and directional pressure relief.
Siemens also offers the 3EP-G porcelain housed surge arresters with short-circuit current capability up to 300 kA for the overvoltage protection of generators and motors.
Siemens 3EK4 and 3EK7 silicone rubber surge arresters with cage design effectively protect medium-voltage distribution networks from overvoltage.
Siemens 3EK4 and 3EK7 cage design surge arresters are ideally suited to provide reliable protection for:
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 offers two types of products for use in distribution networks that differ in terms of 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.
Siemens 3EK8 silicone rubber surge arresters with wrap design effectively protect medium-voltage distribution networks from overvoltage.
Siemens 3EK8 wrap design surge arresters are ideally suited to provide reliable protection for:
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.