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:
•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 offers two types of products for use in distribution networks that differ in terms of mechanical strength:
•3EK4 – for rated voltages up to 36 kV, high mechanical strength
•3EK7 – for rated voltages up to 60 kV, very high mechanical strength