Surge Protection for Rail Traffic

Surge Protection for Rail Traffic

Created by: Glen Zhu | Updated Date: October 3rd, 2023

Surge Protection for Railways

With the drive towards the expansion of the electrification of the rail networks, connection improvements, dedicated High-Speed Lines, an increase in rolling stock and the commitment to integrated transport systems, they have all added greater use to our modern rail systems.

The management of this is made easier with the advances in technologies in power distribution, signaling, control and data communications etc. With so much reliability on electronic technologies, we must not forget the widespread damage that comes with overvoltage power surges that we cannot see. The easiest to understand are those derived from lightning strikes as they can be seen.

With this said, in a typical storm more than 10,000 strikes will not be visible but each can contain enough voltage to cause damage to this sensitive equipment. The Railway and Tram systems today need surge protection for electrical equipment in the total infrastructure.

We have an extensive portfolio of Type 1, Type 2 and Type 3 products providing over-voltage protection for all types of buildings and stations.

Railway systems are highly sensitive and thus over voltage and over current induced by lightning stroke will damage all kinds of equipment via power supply and signal transmission channels and threaten the safety and normal operation of the railway system. Power supply cables and all kinds of electronic and signal equipment must with proper SPDs.

LSP is proud that our surge protection devices (SPDs) are protecting the India Railway. It proves that our SPD is doing a great job in protecting the most mission-critical asset in a country with the most frequent lightning strikes.

Avoid system downtime and disruptions

Railway lines branch out widely over great distances. In a storm, their expansiveness and exposed position make them the perfect target for lightning.

Railway buildings, systems and electronic devices are also vulnerable to lightning strikes and other electromagnetic sources of disturbance.

Damage is caused by direct lighting strikes in the overhead contact lines, rails or masts.

The danger from indirect lightning strikes should also not be underestimated; Induced over-voltages and partial lightning currents, e.g., from a lightning strike in a nearby system, present a considerable risk.

Over-voltages specific to the railway which are evoked, e.g., by switching operations or permanent interference voltage in nearby trackside cables are an additional threat.

As modern control and safety technology is regulated by highly sensitive electronics, it is particularly susceptible to faults.

System failure due to lightning and over-voltages leads to late trains and often high costs.

However, it is possible to increase availability, even during thunderstorms, with a carefully planned lightning protection concept.

Reduce costly disruptions and minimize system downtime… with a comprehensive lightning and surge protection concept tailored to your special requirements.

Reasons for disruptions and damage

These are the most common reasons for disruptions and damage:

  • Direct lightning strikes

Lightning strikes in overhead contact lines, tracks or masts usually lead to disruptions or system failure.

  • Indirect lightning strikes

Lightning strikes in a nearby building or the ground. Overvoltage is then distributed via cables or inductively induced, damaging or destroying unprotected electronic components.

  • Electromagnetic interference fields

Overvoltage can occur when different systems interact due to their proximity to one another, e.g., illuminated sign systems over motorways, high-voltage transmission lines and overhead contact lines for railways.

  • Occurrences within the railway system itself

Switching operations and triggering fuses are an additional risk factor because they can also generate surges and cause damage.

Surge protection of electronic and digital interlockings

Signaling and control systems are the brain and nervous system of railway transportation systems. As the cables run alongside the tracks for many kilometres, they are particularly susceptible to electromagnetic disturbances.

Time and again lightning strikes cause breakdowns in the systems controlled by the interlockings – resulting in tedious delays in the train schedule.

Although conventional interlockings with relay technology have a higher insulation and dielectric strength, system failure is not uncommon. An insulation strength of up to 5 kV is no obstacle whatsoever, even for small lightning flashes.

Hence, it is only a question of time when the damage will occur. This problem is even more acute for electronic interlockings.

Due to the use of electronic components with less dielectric strength, the difference between the low dielectric strength of the system and the influence of impulse voltage from lightning is increasing. In plain language, the insulating strength of the system alone is no longer sufficient.

The large-scale expansion of digital interlockings is intended to provide the solution to many future tasks like, e.g. securing the transnational migration of the ETCS1).

A major advantage of the IP-based, digital generation of interlockings is, above all else, the establishment of central technical locations with the effect of separating energy and data. The increased vulnerability to surges is a permanent problem here, too.

Individual protective measures can improve the situation, but do not always lead to the desired results because the planning is rarely comprehensive.

Effective protection of all generations of interlockings is only possible through the consistent implementation of a bespoke comprehensive lightning protection zone concept for the system in question. This must incorporate all system components like, e.g., point controls, track release, signalling and control technology, etc. It makes it possible to plan, execute and monitor protective measures. All aspects of external lightning protection, earthing and surge protection are considered holistically and at a cost which is economically justifiable.

Surge protection of level crossing safety systems

Level crossings are now, more than ever, neuralgic points whose protection requires maximum reliability.

Level crossings systems ensure that intersections where a railway line crosses a road or path at the same level are safe. Modern level crossing systems can either be integrated in an interlocking or function autonomously.

Nowadays, they are equipped with fully electronic high-performance control technology and are, therefore, particularly vulnerable to disturbances such as direct lightning or surges.

As level crossings cover a wide area, the peripheral elements are often a considerable distance away from the switching house. Field impulses triggered by lightning strikes can generate induction voltage in conductor loops and switching circuits which far exceeds the insulation strength of the electronic/electric devices in use.

Focus on safety: make sure that level crossings are fully operational – even during storms.

Surge protection of GSM-R transmitting and receiving systems

GSM-R stands for Global System for Mobile Communications-Railway and is the core system for communication and data transmission in the ETCS.

Most GSM-R (Global System for Mobile Communication – Railway) radio masts are in exposed locations in order to ensure a good transmission range. As a result, the risk of a direct lightning strike is particularly high. Professional lightning and surge protection is essential to maximize system availability and protect people in the vicinity.

Surge protection of electric point heaters

Points ensure that the train keeps going in the right direction. Electric point heaters are used to make sure that the points also function properly when there is snow and ice, so that railway traffic is not disrupted. At 10-20 kW, the heating output is comparable with that of a single-family home. The stock rails, locking box, moveable frogs and point blades are all heated. A measuring sensor detects all relevant environmental data like precipitation and temperature. This information is collected and evaluated in a control cabinet. The point heating is only activated when the weather conditions require it.

The electricity supply comes either from the public mains or, preferably, from the traction power system (overhead contact line). When fed via the overhead contact line, the corresponding high-voltage transformer cells also need to be fitted out: working according to the 5 safety rules requires, among other things, voltage detectors to check that no voltage is present and EaS devices for earthing and short-circuiting the system.

A well-functioning lightning protection zone concept must be drawn up to prevent lightning, surges and electromagnetic interference from disabling the complex point heating system. The lightning protection zone concept makes it possible to plan, execute and monitor protective measures. All aspects of external lightning protection, earthing and surge protection are considered holistically and at a cost that is economically justifiable to ensure that the relevant devices, facilities, and systems are reliably protected.

Surge protection of direct current railway systems (tram, urban railway, underground railway)

The constant growth of urban centers worldwide necessitates further expansion of local public transport. Direct current urban and underground railway systems are becoming more important and being extended. Different DC voltages from 220 to 3000 V require special protective circuits. A specific characteristic of direct current railway systems is the insulated track installation. Prior planning of the earthing and the clever application of selected earthing components can defuse potential problems, like adverse stray current corrosion, in advance.

However, as well as earthing the tracks, special attention should also be paid to the earthing of shelters (stops): if a lightning flash finds its way to earth in this area, there may be increased step voltage with fatal results! In order to comply with the duty to ensure public safety, measures must be taken to eliminate this risk by way of precise potential control using special mesh mats.

Similarly, in the event of certain faults like, e.g., when an overhead contact line breaks, impermissibly high touch voltage may occur and directly endangering people. So-called voltage-limiting devices are installed to prevent the occurrence of dangerous over-voltages between the insulated tracks of electric railways and the earthed system parts. EN 20122 also refers to the application of these devices for so-called “open traction system earthing”. Their job is to permanently connect system parts in the overhead contact line and the pantograph zones with the return circuit as soon as the threshold voltage is exceeded.

We support you with our tried and tested concepts: so that people and systems are protected against the perilous effects of lightning and surges at all times.

Surge Protective Devices for Railway Infrastructure

LSP has been focusing on the development and production of surge protective devices and their application for more than 12 years. Therefore, we offer a comprehensive SPD portfolio for railway technology.

AC power supply

Coarse and fine AC inputs surge protection for any distribution network type – high-performance lightning surge arresters with pluggable modules installed in the solid base for easy replacement, remote signaling of status and robust construction with impulse current load up to 50kA per pole. Advanced combined type 1+2 surge arresters FLP-B+C MAXI for general applications are also available.

DC power supply

Surge arresters to protect DC inputs of railway devices placed outside buildings, AC/DC and DC/DC inverters and DC distribution controllers. Various models with parallel pluggable modules and remote monitoring or serial specials with an integrated low-pass filter for PLCs or similar interference-sensitive solutions.

LED lighting

Modern LED lighting of railway stations, freight stations and workshops, they are sensitive to overvoltage and need specially designed surge arresters.

Signaling circuits

The railway has long been using electrical signals to monitor the status or control of railway operation systems. This is essential to ensure safe and smooth operation and must therefore be protected. LSP has wide variety of products for analog and digital circuits covering all possible configurations, operation voltages and signal types (such as serial data RS-485, RS-232, current loops, sensors, single unsymmetrical or paired symmetrical signals) including combined ones for signaling and power. Most types have combined elements of coarse and fine protection and selected ones are available also as a slim terminal block type.

Fuel depots, pumping stations, insulated constructions

Isolating spark gaps (ISG) could be used to connect and protect insulated piping parts or similar technologies.

SCADA, data networks, communication modules

LSP provides comprehensive reliable protection of railway infrastructure against overvoltage and lightning surges.

Surge Protection for Rail Traffic

In the rail transport, both the underground and the above-ground railway or tram transport, attention is turned to the safety and reliability of the traffic, and to the unconditional protection of persons. Installed electrical and electronic equipment of the infrastructure (control systems, signaling ones, information ones), has to provide a high level of reliability corresponding to the needs of a safe traffic and protection of persons. Due to economic reasons, equipment does not have sufficient dielectric strength for all potential overvoltage, and therefore, the overvoltage protection has to be adapted to specific requirements of the rail transport.

Surge protective devices for railway telecommunications

Communication infrastructure must be protected against overvoltage surges to ensure its reliability, which is essential for the safe and smooth operation of the railways.

LSP offers a complete range of surge protective devices to protect AC or DC power inputs, radio receivers and transmitters (coaxial SPDs), Ethernet data lines (including POE), RS-485 lines, and more.

Protection of GSM-R transmitting and receiving systems

GSM-R stands for Global System for Mobile Communications-Railway and is the core system for communication and data transmission in the ETCS.

Most GSM-R radio masts are in exposed locations alongside the railway tracks in order to ensure optimum radio coverage and a good transmission range. As a result, the risk of a direct lightning strike is particularly high. Professional lightning and surge protection is essential in order to maximize system availability. Insurance companies and experts regard the consideration of lightning and surge protection measures when planning and installing mobile communication facilities as an integral part of the protection of people and property.

Rail Traffic Surge Protection

Lightning strikes can cause catastrophic damage to critical rail infrastructure and equipment. Unexpected transient events or momentary bursts of extremely high voltages can occur even during normal operations, which is why railway electrical protection is an important part of safe, reliable operations. LSP offers solutions that provide critical electrical protection for railway properties and assets including classification yards, buildings and structures, bungalows, movable bridges and other areas throughout the network that contain sensitive equipment. This product range includes solutions for direct strike lightning protection, grounding and bonding, as well as surge protective devices (SPDs) for railway communication/signaling equipment and systems.

LSP is a leading global supplier of SPDs, serving a diverse range of industries throughout the world with surge protection solutions for equipment power, equipment inputs and outputs as well as data and telecom transmitting equipment. With our specialization in railway electrical protection, LSP offers many SPDs that are specifically designed for rail applications. We offer SPDs with conventional surge technologies such as: metal oxide varistors (MOVs), silicon avalanche diodes (SADs), gas discharge tube (GDT) and spark gap technologies. With a long-term commitment to R&D, and a world class electrical engineering lab, we have developed novel LSP surge suppression technologies that overcome the limitations of conventional methods to provide an enhanced level of protection.

Rail Power Surge Protection

Power supply protection is an important part of safe, reliable railways. Lightning can induce surges on main power lines, resulting in a power line fault that lasts much longer than a typical transient event, which can cause significant damage to network equipment. LSP offers a comprehensive range of surge protection devices for rail power supply, including devices that protect primary and secondary power distribution equipment.

Surge Protection for Data and Telecom Equipment

Rail communication equipment and systems are the foundation of railway signaling.   Increasingly advanced technology is being introduced into rail networks, driving next-generation railway technology with new signaling systems such as communication-based train control (CBTC), as well as safety overlays such as PTC (U.S.) and ERTMS (European /global).  LSP offering a complete range of surge protection devices (SPDs) for sensitive equipment and systems used to transmit radio frequency and data across the network.

SPDs for Railway Equipment I/Os (Inputs and Outputs)

The railway signaling ecosystem includes a large and diverse array of interconnected electrometrical and electronic equipment located along the wayside (adjacent to the tracks) as well as in nearby signal houses (bungalows).  LSP offers a wide range of SPDs to protect inputs and outputs (I/Os) ofthese critical railway signaling mechanisms.

Six Point Protection

LSP Six Point Protection is a system that provides comprehensive electrical protection for railway infrastructure and assets by integrating solutions for lightning protection, grounding and bonding, and surge protection. Each solution is comprised of a custom combination of LSP products arranged to meet the unique electrical protection requirements of each site. Together, these solutions bring a coordinated approach preventing many types of electrical damage, including lightning strikes and transient over-voltages, and provide general best practice electrical protection during normal operations.

The LSP Six Point Protection provides an approach to

(1) Capture the lightning strike,

(2) Convey this energy to ground,

(3) Dissipate the energy into the grounding system,

(4) Bond all ground points together,

(5) Protect incoming AC/DC power feeders,

(6) Low Voltage Surge Protection for (a) Wayside signaling equipment I/O, and (b) Surge protection for data and telecom equipment.

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Reliability in surge protection!

LSP’s reliable surge protection devices (SPDs) are designed to meet the protection needs of installations against lightning and surges. Contact our Experts!

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