Surge arresters for railway applications — Product guide

Reliable, stable, and safe overvoltage protection

Siemens Energy medium- and high-voltage surge arresters protect electrical power supply equipment against lightning and switching overvoltages, drawing on continuous R&D and worldwide field experience dating back to 1925. In railway systems they prevent lightning overvoltages from damaging the insulation of system components and the traction vehicles themselves, protecting traction substations, transmission lines, cables, catenary systems, and rail vehicles for local, long-distance, and high-speed service.

The portfolio is suited to every rail application — high-speed and intercity trains, commuter and regional trains, urban transport (light rail, metros, streetcars, eBus), locomotives, propulsion systems, rail electrification, catenary power supply, substations, and A1/A2 surge arrester applications — and to every rail power system: 12.5 kV at 25/60 Hz, 15 kV at 16 2/3 Hz, 25 kV at 50/60 Hz, and 750 V, 1500 V, and 3000 V DC.

Key design demands met across the range include high mechanical stability against vibration and high wind speeds, extremely reliable pressure relief behavior where special protection is required, and excellent pollution layer characteristics for coastal, desert, and heavily polluted regions.

Standards and testing

All Siemens Energy rail surge arresters comply with the latest versions of IEC 60099-4 (metal-oxide surge arresters without gaps for AC systems), DIN EN 50526-1 (railway applications — DC surge arresters and voltage limiting devices), DIN EN 45545-2 (fire protection on railway vehicles), and IEC 61373 (rolling stock equipment — shock and vibration tests). Tests are performed by independent laboratories with reports available on request.

Every arrester undergoes a routine test and ships with a routine test certificate. Siemens Energy meets all requirements of ISO 9001:2008, ISO 14002:2004, and BS OHSAS 18001:2007, and all suppliers are ISO-certified or audited by Siemens Energy.

Product range

Four arrester families cover AC and DC rail applications. The 3EB4 uses a fiber-glass reinforced plastic (FRP) hollow core with silicone rubber sheds; the 3EB5 uses the Cage Design with a directly molded silicone rubber housing; the compact 3EB2 and 3EB3 are silicone-housed DC arresters for urban transportation and rail electrification.

3EB4 silicone rubber surge arrester with composite hollow core design

The 3EB4 was designed for outstanding safety and durability: it is hydrophobic, withstands weather extremes from -40 °C to +70 °C and UV radiation, and its resilient technology and durable materials ensure smooth operation in all conditions. The composite hollow core design molds silicone directly onto a fiberglass reinforced plastic (FRP) tube, giving very high withstand capability against mechanical forces; special sealing of the flanges at both ends prevents partial discharges and moisture ingress for decades of trouble-free service.

Main components: silicone rubber sheds directly molded on the FRP tube, the FRP tube itself, end fittings with a directional pressure relief device and sealing system, metal oxide resistors, and an arcing horn.

In case of overload or the extremely rare case of an arrester short circuit, the arc escapes through the directional pressure relief device, so the arrester can be pointed in a direction that minimizes risk to nearby equipment and passengers. Internal parts are not ejected and the shatterproof housing does not break. 3EB4 arresters are suitable for rail vehicles up to 420 km/h (260 mph) and for stationary applications in areas accessible to the public.

Two mounting variants are coded by the type extension: -0D mounts on ø140…162 mm with 3×M10, grounded; -0E mounts on ø260 mm with 3×M12, grounded, adding 2.3 kg.

Surge arrester 3EB4 — electrical characteristics

Residual voltage columns give maximum values at discharge currents 30/60 µs 0.5/1/2 kA and 8/20 µs 5/10/20 kA, all in kV. In = nominal discharge current, Qn = charge transfer rating, Wth = thermal energy rating. The trailing squares in the type code select the mounting extension (-0D or -0E).

Surge arrester 3EB4 — mechanical characteristics

Rows correspond one-to-one with the electrical characteristics table above. SSL/SLL = specified short-term/long-term load; withstand voltages are lightning impulse 1.2/50 µs and power frequency 1 min wet.

3EB5 surge arresters with silicone rubber housing and Cage Design

The Cage Design of the 3EB5 delivers high mechanical strength, safe overload performance, and maintenance-free reliable service. The metal oxide resistors (MOVs) are enclosed by a cage of fiber-glass reinforced plastic (FRP) rods, forming a rigid, reinforced structure. The self-extinguishing, flame-retardant silicone rubber housing is directly molded onto the MOVs and FRP rods for excellent sealing: all components are completely embedded, inclusions and gaps are avoided, and partial discharges and moisture ingress are prevented. The hydrophobic silicone is permanently water-repellent and stain-resistant, giving high tracking and erosion resistance.

Main components: cage of FRP rods, metal oxide resistors, silicone rubber sheds directly molded on the MOVs and end-fittings, and the end-fittings themselves.

Because the MOVs are not enclosed in a sealed mechanical shell, an arc from the extremely rare event of MOV overload escapes directly through the soft silicone housing. Arcing cannot build critical internal pressure, the mechanical support structure remains unharmed, and ejection of internal parts that could damage nearby equipment is prevented almost completely. 3EB5 arresters are suitable for rail vehicles up to 320 km/h (200 mph) and for stationary application in areas accessible to the public.

Surge arrester 3EB5 — electrical characteristics

Same column conventions as the 3EB4 table; all 3EB5 types use the -0D mounting (ø140 mm bolt circle, M12x20) with M12x24 / M16x32 terminals.

Surge arrester 3EB5 — mechanical characteristics

Rows correspond one-to-one with the 3EB5 electrical characteristics table above.

3EB2 and 3EB3 surge arresters for A1 and A2 applications

For DC systems, VDV 525 (Publication No. 525 of the Verband deutscher Verkehrsunternehmen, the Association of German Transportation Companies) recommends effective overvoltage protection against lightning strikes. Rails isolated from earth require low-resistance tower footings, driven piles, concrete-track reinforcements, or separate earth rods for earth termination; rails without additional isolation generally have low leakage resistance and can serve as earth terminations, but discharging surge currents through the rails endangers electrical and electronic equipment near or on the tracks — additional surge arresters within such equipment are an effective remedy.

Full catenary protection is achieved by installing outdoor 'A1' surge arresters at every power feeding point, at the ends of feeding sections and dead-end feeders, at coupling points, and at current taps; additional A1 arresters are recommended for sections frequently hit by lightning, such as bridges or open stretches.

At substations, protection of supply and return lines requires 'A1' arresters connected between section circuit breakers/cable terminals and the return line, and 'A2' arresters between the return line and structure earth to limit the unavoidable potential rise caused by lightning surge currents in a return line. Although MOV arrester failure rates are well below 0.1 percent per year, a failed A1 arrester can become permanently conductive and hold inadmissibly high fault voltage on the ground electrode; an additional A2 arrester with low continuous operating voltage (120 V <= Uc <= 300 V) between ground electrode and return line is then intentionally overloaded to limit the fault voltage and trip the section circuit breaker via feeding from the catenary system.

3EB2 and 3EB3 — electrical and mechanical characteristics

The 3EB2 (200 mm high, 1.2-1.4 kg, classification DC-B) and 3EB3 (270 mm high, 5.6-6.4 kg, classification DC-C) are compact silicone-housed DC arresters rated for travel speeds up to 160 km/h. Residual voltage columns as in the tables above.

Packing dimensions and replacement types

Shipping carton dimensions: 3EB2 (all housings) 230 x 190 x 150 mm; 3EB3 (all) 330 x 250 x 140 mm; 3EB4 housings M and S 260 x 235 x 240 mm, housing L 300 x 270 x 260 mm, housing X 300 x 270 x 540 mm; 3EB5 (all) 290 x 280 x 560 mm.

The guide closes with a cross-reference from phased-out 3EB1, older 3EB4 (-x2/-42 series), and 3EL2 types to their current 3EB4/3EB5 replacements, reproduced below.

Figures & drawings

Click any figure to enlarge.