Medium-voltage arresters for distribution networks

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.

We offer the 3EQ0 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

In addition to providing maximum protection against overvoltages, Siemens Energy 3EP porcelain surge arresters feature a specially developed directional pressure relief system. In the event of an overload, the arc can escape directly through the directional pressure relief device. Strong, high-quality porcelain prevents pressure from building inside and internal parts from being rejected. This reduces, even minimizes the risk of damage to facilities or injuries to people in nearby.

Siemens Energy offers the 3EP-G porcelain surge arrester, which has a short circuit current of up to 300 kA. It is ideal for overvoltage protection for generators and motors that require a very high short circuit current.

The excellent sealing system on the 3EP-G surge arrester effectively prevents moisture ingress and partial discharges, guaranteeing decades of trouble-free operation. The use of non-porous sulfur cement instead of corrosive Portland cement protects the metal oxide blocks and prevents the effects of aging.

The metal oxide blocks in the 3EP-G surge arrester are enclosed in a rigid, reinforced structure made of fiberglass-reinforced plastic (FRP) rods.

Siemens Energy type 3EP-G porcelain surge arresters 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