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April 2020 – Benefits of Mersen’s Surge Arresters

Published on: 03/04/2020

GD Rectifiers discusses the benefits of using Mersen’s Surge Arresters

Mersen's Surge Arresters.

Mersen’s lightning arrester enclosures are designed to protect railway networks against disturbances incurred by lightning, in the feeding lines in the substations along with the railtrack (pole enclosure) as well as in the power lines mounted on the roof (pantograph enclosure).

Choosing the right design for your application can be hard, with so many products available, each comprising of a different specification.

GD Rectifiers shares the benefits of using Mersen’s 10kA and 20kAmp lightning arrester.


Mersen’s Surge Arresters: The Benefits

The usual solution consists of placing an air breaker and a non-linear resistance in silicon carbide between the line and the ground. The system presents several drawbacks:

  • It does not age well
  • This malfunction triggers the opening of the line circuit breaker which interrupts the service
  • The new solution is made up of the combination in series of a non linear zinc oxide resistance and a current limiting fuse
  • The zinc oxide resists better to aging thanks to better non-linearity coefficient
  • In spite of this, should a lightning surge be violent enough to damage the lightning arrester, then the fuse will isolate the faulty equipment, leaving the feeding of the railway line in service



One of the essential elements of the system is that it is a first with a distant warning signal of the lightning arrester being isolated. The railway network operator has the advantage of detecting very rapidly the protections.


Design Guide

Mersen proposes to use zinc oxide varistor combined with fuse and an electric signalling system, which now makes it possible to:

  • Vastly improves the quality of the power line protection by better peak let-through in overvoltage conditions. This is due to zinc oxide’s non linearity factor, which is more suitable than silicon carbides
  • Eliminates the products life span and improves peak let-through over time, because ZnO retains its initial properties better and longer
  • Avoids disturbing operation when the product has aged due to lightning striking too many times or too hard
  • Simplifies maintenance – the defective device is immediately isolated and the blown fuse detection device trips a micro-switch to give remote warning of the state of the system. The element to be replaced is identified immediately.
  • Operation: instantaneous automatic, self-restoring, no power follow current, only voltage spikes clamped
  • Connections: no 8 AWG cables for plus and minus terminals
  • Power consumption: none except few milliamperes for indicator lamps and relay coil



Railway networks protection against disturbances incurred by lightning.


Technical Data

Voltage Range AC 500-750Vac
Breaking Capacity 100kA surge fuse
Speed/Characteristic 1 nanosecond
Switchability Bidirectional, same preference on either polarity
Working Temperature -55°C to +85°C
Air Quality Salt-laden atmosphere, dry and dusty (0.1mm to 1mm airborne particles), any ozone condition, acid rain, presence of SO2
Humidity 95fi non-condensing maximum


Download the 10kA and 20kAmp Lightning Datasheet here


GD Rectifiers has been an authorised distributor for Mersen for over twenty years and offers customers their extensive range of fuses, high voltage IEC fuses, low voltage IEC fuses and surge arresters.


For further information on Mersen’s 10kA and 20kAmp lightning arrester please contact GD Rectifiers on: 01444 243 452 or email:


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