Lightning and Surge Protection for Telecom

Lightning and Surge Protection for Telecom

Created by: Glen Zhu | Updated Date: November 30th, 2023

Lightning and Surge Protection for Telecommunication

“Ever found yourself on the edge during crucial moments? Picture this: deadlines looming, video calls in progress, or emergencies unfolding. It’s in these make-or-break instances that the worry intensifies will our signals endure the storm?

How about you? Have you ever experienced this type of nerve-wracking moment?

Telecommunication systems and potential risks

Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. At its core, telecommunication involves the encoding, transmission, and decoding of information, enabling the exchange of messages and data between individuals, businesses, and devices across vast distances.

The telecom system includes the entire sets of equipment, protocols, and technologies involved in the transmission of information over a distance. The role of telecom has become more crucial than ever due to the increasingly interconnected world, making its safe and uninterrupted connection and network equally important.

Any disruption or disconnection in one part of the globe can greatly impact not only local production but also the daily lives of people on the opposite end of the earth. However, telecommunication facilities are highly vulnerable to transient overvoltage surges posed by direct or indirect lightning because of their extensive network infrastructure and the nature of the communication medium.

The susceptibility of the system to lightning-induced surges arises from the reliance on various electronic devices, cables, antennas, and towers that form the key framework of the communication infrastructure. The extensive cabling and wiring deployed in telecommunication networks act as antennas, inadvertently capturing electromagnetic energy from lightning discharges. The breakdown of communication systems could lead to significant loss of life or property and result in various other forms of damage.

Stages of lightning strikes:

The process of lightning attachment involves a step leader connecting with objects such as antenna structures or signal/power cables on a tower, leading to potential severe damage, fragmentation, and falling debris that can harm objects below. This attachment may allow the lightning current to enter connected cables, posing hazards to both equipment and personnel in the base transmission station.

Subsequently, the lightning current travels to the ground, posing risks of melting or burning materials and side flashing to nearby objects, generating a substantial electromagnetic field with voltage impulses that can damage nearby electrical systems. Upon reaching ground level, the establishment of a low-impedance path becomes crucial for the swift dissipation of the current; otherwise, surface routes may be taken, resulting in injuries, equipment damage, and the initiation of fires or explosions.

Lightning rods inadequate for antenna towers

Lightning rods serve as primary devices for safeguarding various structures against the destructive forces of lightning. Yet, the dynamics differ when it comes to the application of radio tower lightning protection. Telecommunication towers are constructed using materials such as steel, which boasts high conductivity and they are intentionally designed to be tall and situated in remote locations to optimize signal transmission and coverage.

Despite the installation of lightning rods, the towering structures themselves, especially the antennas within the structure, become preferred conduits for the lightning current. The occurrence is rooted in the inherent tendency of lightning currents to navigate through larger and more conductive pathways. The capacity of the lightning rod to conduct electrical energy, while substantial, pales in comparison to the overall size of the tower.

This does not suggest tower lighting rods are ineffective for tower lightning protection; rather, their effectiveness is contingent upon proper coordination with other lightning protection devices. For instance: telecom surge protector.

Tower structure and apparatus positioning

As commonly known, lightning tends to strike taller structures due to the concentrated electric fields at their peaks. It’s worth noting that structures under 100 meters in height are less prone to lightning strikes, as indicated by empirical data. Cellular antenna towers typically range from 15 to 80 meters in height, making them less susceptible to lightning strikes.

In urban areas where antenna towers coexist with tall structures like buildings and power towers, there is competition for lightning triggers. Taller structures, including antenna towers, offer a cone of protection, shielding shorter elements within the cone from direct strikes.

Addressing the need for vertical antenna lightning protection is crucial in mitigating risks associated with lightning-induced damage, ensuring uninterrupted communication services. To enhance safety, tower design should carefully consider the placement of antennas and electronics, ensuring they are positioned well below the structure’s highest point. It aims to designate the tower itself as the primary target for a direct strike, thereby minimizing the risk to the equipment.

Grounding / earthing

The grounding system is critical to the lightning protection of telecom facilities. Grounding equipment such as ground rods, ground mats, ground bars, etc, are indispensable for providing comprehensive lightning protection systems for telecommunication networking against the looming threat of lightning strikes.

In addition to facilitating the dissipation of lightning currents, grounding systems help in maintaining equipotential bonding within a telecommunication setup, which ensures that different elements of the system remain at the same electrical potential. The importance of equipotential bonding lies in its ability to minimize the risk of side flashes and potential differences that could otherwise lead to severe damage to sensitive equipment.

Figure 1 – Outdoor earthing layout

The illustration showcases the outdoor configuration of a grounding system in a telecommunications facility. However, implementing this arrangement may not always be feasible due to specific site constraints. In situations where telecommunication equipment is situated within a sizable multifunctional building or on multiple floors above the ground level, adopting this particular layout may prove impractical. In such cases, it becomes necessary to evaluate alternative outdoor ground electrode systems on a case-by-case basis if the suggested configuration below cannot be implemented.

Figure 2 – Indoor grounding layout

Ground rods

Ground rods, also known as grounding electrodes or earth rods are the most commonly used device in serving the function of grounding. Typically made from materials like copper or copper-coated steel, ground rods are designed to establish a secure electrical connection with the Earth. The installation of ground rods involves driving them vertically into the ground, and the depth of installation is determined by factors such as soil resistivity.

The copper-bonded ground rod has a layer of copper coated over a nickel layer. This helps create a strong, lasting connection between the copper and the steel core. Copper-bonded ground rods are more recommended because the copper coating doesn’t slip or tear when driven, and it won’t crack if the rod is bent. The tough, carbon steel core is good for deep driving. These rods resist corrosion well and provide a smooth path to the ground.

It’s worth noting that some types of soil and landfill areas might not work well with copper. In such cases, stainless steel is a better option. Stainless steel can also be used when there are nearby structures like steel towers or poles, or if there are lead-sheathed cables close to a group of ground electrodes. Under these situations, it’s important to think about the possibility of galvanic corrosion.

The applied ground rods and installation must be chosen and performed according to the standards regulated in IEC 60364-4-41, IEC 62305, and IEC 62305-3.

VDSL 2 Vectoring / Super Vectoring

VDSL2, or Very High Bitrate Digital Subscriber Line 2, is a broadband technology designed to enhance traditional copper telephone lines for high-speed internet access. At the core of its performance improvement is vectoring, which tackles crosstalk challenges arising from signal interference among adjacent lines within a cable bundle. Utilizing advanced algorithms, vectoring analyzes crosstalk and generates anti-phase signals to counter interference, thereby enhancing the stability and overall performance of VDSL2 connections.

Extending the capabilities of vectoring, Super Vectoring operates on a broader frequency range, facilitating increased data rates and extended coverage. Also referred to as VDSL2 Profile 35b, Super Vectoring incorporates vectoring technology to mitigate crosstalk, ensuring accelerated downstream and upstream data rates over short to medium distances. This positions Super Vectoring as an attractive option for service providers aiming to deliver improved broadband speeds to customers over existing copper infrastructure.

Under VDSL 17a vectoring, a data rate of up to 100 MBit/s is achievable, but this is subject to reduction due to factors like increased line length and an unfavorable infrastructure. VDSL 35b Super Vectoring, as an extension of vectoring technology, aims to minimize interference from crosstalk in primary telephone cables. Each connection undergoes analysis for potential interference, and signals are adjusted accordingly, enabling a higher data transmission rate of up to 300 Mbit/s. However, to maintain the full 300 Mbit/s, the maximum line length from the DSLAM to the end customer is restricted to 300 m, or even shorter if the infrastructure is less than ideal.

Figure 3 – Performance per line pair with different transmission technologies

Insulation

Equipment and cable insulation in the telecommunication service industry is essential to guarantee the dependability of communication and data transmission. Apply properly designed cabling and meticulous installation contribute to system reliability. Adhering to industry standards, such as the TIA-568 series and IEC 60332-1, where specific requirements for insulation in telecommunications cabling are outlined.

Telecom surge protector

Surge protection for telecommunication networks is crucial to make sure all the equipment and infrastructure therein are protected from transient voltage spikes or surges. Implementing effective surge protection measures helps prevent damage to sensitive telecom equipment and ensures the continuity of communication services. Here are key areas that need to be installed with surge protective devices within residential buildings:

Primary Protection:

Type 1 Surge protectors FLP25-275/3S+1 are installed at key entry points of the telecom system and power supply system to intercept surges before they reach sensitive equipment.

This primary protection is typically deployed at the network’s point of entry, where communication lines enter a building.

Secondary Protection:

Additional surge protection devices, for instance: SLP40-275/3S+1 are often employed at critical points within the network, such as distribution frames, server rooms, or data centers.

The secondary protection measures help further mitigate the risk of voltage spikes as signals travel through the network infrastructure. This multi-layered approach enhances the overall resilience of the telecommunication system.

Equipment Protection:

Individual pieces of telecom equipment, such as routers, switches, and modems, may have built-in surge protection features.

However, in areas prone to frequent surges or lightning activity, supplementary surge protection devices can be installed directly on the power and signal lines connected to low-voltage devices to provide an extra layer of defense.

TLP series DIN-rail mounted surge protective device from LSP is a great choice when considering specific point-to-use protection for 24V 48V 60V 120V 230V, in coordination with Type 2 arrester installation head.

Future standard surge protection:

Given the sensitivity of modern technology, careful consideration is essential when choosing protective devices to mitigate the impact of lightning and surges. Recognizing the limitations of commonly used arrester technologies that often result in speed loss. To accommodate upcoming transmission technologies such as VDSL2 Vectoring, VDSL Super Vectoring, or G, adjustments are necessary.

The selected devices should ideally have minimal impact on the customer’s bandwidth. To prevent intermodulation distortions on the line, it is crucial to opt for protective devices comprised of linear components. Devices equipped with non-linear components, such as semiconductors, can lead to a reduction in data rates at the end customer, sometimes significantly.

Monitoring and Maintenance:

Regular monitoring of surge protection devices and conducting preventive maintenance are essential for ensuring their continued effectiveness. Periodic inspections and testing can identify any issues with the surge protection system, allowing for timely replacements or upgrades.

Surge protection for residential buildings

In addition to mobile tower lightning arresters, surge protection is imperative for residential buildings as well. They are often vulnerable to damage caused by lightning strikes and transient surges.

Figure 4 – Schematic diagram of a communication network in a residential building

The primary reason can be attributed to the lack of proper lightning protection measures in place. transient overvoltage surges can cause significant damage to the electrical systems, appliances, and electronic devices in residential buildings, disrupting the peacefulness of daily life.

For buildings that do not have external lightning protection devices, the installation of combined surge protective devices FLP7-275/3S+1 on a DIN rail at main distribution boards is needed.

This ensures the uninterrupted operation and longevity of the building’s electrical infrastructure. FLP7-275/3S+1 can withstand nominal and maximum discharge currents up to 25 kA and 50 kA.

A combined arrester for telecommunication connection is installed directly after the Network Termination (NT) device or in the multimedia field to protect telecommunication equipment from voltage surges and transient overvoltages. The primary function is to divert excessive voltage and current away from sensitive telecommunication equipment, such as modems, routers, and telephones.

For surge protection of ethernet within residential buildings, the PoE SPD – DT-CAT 6A/EA is a second-to-none option, safeguarding Power over Ethernet (PoE++) networks from transient surges.

Utilizing high-energy gas discharge tubes and silicon avalanche diodes, it shields data-processing equipment by redirecting excess voltage.

Housed in a shielded casing with premium RJ45 jacks, it ensures robust protection against large surge events, preserving the integrity of sensitive devices in residential Ethernet applications.

Conclusion:

In conclusion, systematic lightning and surge protection are imperative for the resilience and longevity of telecommunication networks. When lightning strikes, relying solely on air terminals proves insufficient in effectively safeguarding telecommunication facilities. The best lightning and surge protection for telecom involves a synergistic combination of key components such as tower lightning rods, tower lightning arresters, and grounding systems.

When components collaborate smoothly, mitigating the impact of lightning and surges, telecom networks ensure uninterrupted service, prevent equipment damage, and minimize downtime. As technology advances and telecom networks become increasingly important in our daily lives, the reliability and resilience of modern communication infrastructure depend on proactively investing in countering potential disruptions caused by lightning.

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