Surge Protection for Cell Sites

Surge Protection for Cell Sites

Created by: Glen Zhu | Updated Date: Aug 14, 2023

LSP protects cell sites

The world is currently undergoing significant changes, including the planning and establishment of new mobile radio sites, as well as the revitalization and extension of current network infrastructure. In the era of 5G, the Internet of Things, and autonomous driving, the growing need for enhanced transmission capacities and network availability drives the ongoing expansion of preexisting structures.

These transformations affect the accessibility of installations and systems at cell sites. However, due to the exposed nature of mobile phone masts, they are prone to recurrent direct lightning strikes that disrupt entire systems. Additionally, damage often arises from power surges, like those caused by lightning hitting close to a mobile radio site. Even individuals near these installations during thunderstorms face risks to their safety.

Ensure availability - protect human lives

A thorough lightning and surge protection approach provides optimal safety for people and high availability systems. LSP designs specialized AC and DC Surge Protection Devices (SPDs) for mobile radio sites.

LSP serves as a proficient and trustworthy provider, offering support to network operators, power supply companies, system technology suppliers, installers, and equipment suppliers.

Surge protection for AC applications

5G aims to establish a comprehensive global network, driving the need for more mobile radio sites to manage this technological advancement. However, challenges arise from limited installation spaces and decreasing areas.

Smaller systems are generally preferred due to market developments. Consequently, new protective device solutions are necessary, bringing fresh requirements:

  • Optimal integration into compact mobile communication systems demands small size.
  • Reliable protection of sensitive mobile communication technology necessitates robustness.

Existing protective devices are available in modular or compact formats. Modular setups, like the 3+1 configuration, use 8 modules – often bulky. Compact devices need just 4 modules but lack pluggability.

The solution:

The latest-generation combined arrester cleverly integrates the compactness of 4 or 8 modules and the convenience of a modular protective device.

In AC applications, cell site power supply is distinct from the building’s, forming a separate supply line. Tested surge protective devices (lightning current and surge arresters) shield the main and system power supply infrastructure.

These arresters excel in handling follow currents and limiting them, preventing unnecessary tripping of system fuses. This ensures dependable and highly available operation for cell sites.

Surge protection for DC applications

After securing the AC side with FLP25-275/3S+1 / FLP12,5-275/3S+1 / SLP40-275/3S+1, the focus shifts to safeguarding the DC side. Apart from shielding the power supply, it’s crucial to block surges and lightning currents from entering DC systems.

This is why the standard DIN EN 62305 (IEC 62305) mandates a type 1 lightning current arrester at the boundary between lightning protection zone 0B and 1. In mobile communication stations, this boundary typically aligns with the base station’s outlet.

Protecting the power supply

The DC Box offers an exceptional power supply protection solution, featuring the single-pole type 1 surge protective device FLP25-DC75 (lightning current and surge arrester).

This weather-resistant box is placed right at the base station outlet, effectively blocking partial lightning currents from infiltrating the system. With the coordinated lightning current arrester FLP25-DC75, all incoming conductors to the cell site are securely shielded against surges and lightning currents.

What else needs protecting?

Remote radio units and active antenna systems are directly mounted on the mast, offering clear benefits: minimal signal loss due to short antenna cables and no need for cooling in open-mounted units.

Nonetheless, their exposed placement puts them at risk of lightning-induced damage. Mobile communication components, with their sensitivity and costliness in terms of procurement and upkeep, demand robust protection against lightning and overvoltage damage. A meticulously designed protection strategy is thus essential and advantageous in this context.

The Protection Concept

In practical scenarios, a comprehensive protection strategy can be outlined as follows:

Situation 1

For cable lengths under 20 m between the protective device and the remote radio unit or active antenna system, the DC Box featuring FLP25-DC75 is directly placed at the base station outlet.

Situation 2

When the cable length exceeds 20 m, there’s a possibility of lightning currents coupling due to close proximity to grounding conductors. In such cases, an extra DC Box with the two-pole type 1 arrester, FLP25-DC75, is positioned either near the remote radio unit or on the active antenna system directly at the mast.

More advantages with the DC Box

Cost-Effective Materials

Incorporating an extra DC Box directly onto the mast eliminates the need for individual supply lines to components like the remote radio unit and active antenna system. This not only shortens the total length but also reduces the required conductor material, resulting in cost savings for the project.

Efficient Installation

Installation is streamlined as well. With just one supply line to the DC Box and concise conductors extending to the components, significant time is saved during setup.

Simplified Maintenance

The use of a DC Box allows for direct activation and deactivation of the active transmission system on the mast, eliminating the need to interrupt the power supply at the base. Moreover, the fuse status (on/off) is readily visible, providing installers with added certainty in practical applications.

Surge Protectors for Radiocom Site

Vulnerable mobile installations mobile phone setups face direct and indirect lightning effects due to their elevated placement, pylon presence (raising impact risk), and utilization of delicate equipment, making them prime targets for lightning strikes.

Critical communication risks radiocom sites, vital for communication services, are prone to power surges from lightning strikes. These surges can inflict severe harm on the sensitive systems and equipment at these sites.

Protection through surge protectors Installing surge protectors can mitigate risks for radiocom site owners, ensuring reliable operation of essential communication infrastructure.

Surge protectors divert high electrical currents, shielding equipment, communication continuity, personnel safety, data integrity, and costs.

Wide-scale coverage it’s highly recommended to deploy surge protectors on all external networks to guarantee installation reliability. When lightning rods are in use, Type 1 surge protectors are necessary to ground a portion of direct lightning’s direct current.

All Networks Covered:

  • AC Network (single or 3-phase)
  • 48 Vdc Power Supply
  • Coaxial Cables
  • Telecom Connections

Telecommunication protection telecom lines, susceptible to transient impulses, can suffer damage in exposed areas or longer spans between buildings. Such damage results in pricey repairs. LSP, a professional Telecom Surge Protection device manufacturer, offers solutions safeguarding telecom lines from high electrical surges in primary, secondary, and security setups.

Surge protectors for Telecom and Data networks

Communication and data devices like PBX, modems, and data terminals are becoming more at risk from lightning-caused voltage surges. These devices are getting more intricate, delicate, and have connections that share grounding with other networks. LSP has created surge protectors for Telecom/Data and Industrial networks to address this issue.

When Lightning Strikes, Surge Protection Devices Ensure Cell Towers Stay Online

Among the causes of harmful electrical spikes and surges, lightning strikes from nature can be the most destructive. These interruptions lead to various problems, including the cost of replacing equipment and dissatisfied customers who might switch to different networks.

LSP is an expert in creating and designing parts for surge protection devices in telecommunication systems. These devices shield against high electrical currents and guard against the surges caused by lightning strikes.

How Lightning Strikes Affect Cell Towers

Lightning strikes are an unwanted but unavoidable issue for cell carriers. These towers can be quite tall, ranging from 50 to 200 feet, with some reaching up to 2000 feet. Because they often stand alone, they’re highly susceptible to lightning strikes.

A direct lightning hit can release up to 100,000 volts (sometimes even more), which can seriously damage unprotected equipment. Predicting exactly when and where lightning will strike remains uncertain, despite extensive research. Additionally, the secondary effects of lightning can cause voltage surges that are just as harmful. These surges can happen even if the lightning isn’t very close. As a result, lightning-induced surges occur frequently.

After a lightning event, grounded wiring can carry voltage spikes. Induction loops created by the interaction of power lines and data lines can pick up nearby voltage surges. Weather-exposed overhead power cables can transmit surges over long distances to various distribution systems. Even wires running from tower antennas to the base station can carry surges.

Because sensitive electronics and intricate computers are vital to the infrastructure, without proper protection, induced surges can destroy circuits in connected equipment. This is why installing surge protection devices is crucial to avoid the costs of repairs, replacements, and downtime.

What are Surge Protection Devices, or SPDs?

The main aim of protective solutions for cell towers is to shield sensitive equipment from destructive energy. Surge protection devices (SPDs), discussed in this article, don’t guard against direct lightning strikes. Instead, they provide defense against the effects of lightning that are induced.

To start with, the primary measure for lightning protection is to guide lightning current safely to the ground, avoiding sensitive equipment. Lightning conductors fixed at the tower’s highest point play a vital role in redirecting most of the energetic disturbance.

SPDs, on the other hand, are installed on power distribution boards, signal/data lines, control systems with delicate gear like microprocessors, and other costly equipment essential for operation.

When choosing components for making surge protection devices using current technology, designers need to consider factors such as response speed and the ability to handle current.

Components of Surge Protection Devices

Lightning can cause voltage surges that can spike from zero to several volts in a matter of microseconds. Fuses and circuit breakers, unfortunately, can’t react quickly enough. Effective components often used in surge protection devices (SPDs) to counter these surges are usually one of the following:

Metal oxide varistors (MOVs):

These are solid-state semiconductors usually made with sintered zinc oxide. They can handle high currents when exposed to voltages higher than their rated voltage. They redirect surge currents away from the protected equipment. When chosen correctly, these components, known as Metal Oxide Varistors (MOVs), can restrict voltages to around 3 to 4 times the normal circuit voltage. One drawback of MOVs, similar to Gas Discharge Tubes (GDTs), is their limited lifespan. Their clamping voltage drops with each surge event. If the clamping voltage reduces by over 10%, MOVs are considered to be functionally degraded.

Gas discharge tubes (GDTs):

A sealed glass container holds a gas mixture along with two electrodes. When a strong voltage spike occurs, the electrodes become ionized and start conducting electric current. While Gas Discharge Tubes (GDTs) respond more slowly, they can handle larger surge currents compared to other parts of similar size. However, due to their slower reaction, the circuit they protect might face high voltages before GDTs activate. Also, GDTs have a limited lifespan. Because of this, they are better suited for managing numerous small surges or a few significant ones.

Transient voltage suppression (TVS) diodes:

Commonly called avalanche diodes due to how they work at a tiny scale, these semiconductors react the quickest among protective components (in picoseconds). They generally have a lower ability to absorb energy, though their lifespan is remarkably long when chosen appropriately. However, if faced with surges beyond their capacity, TVS diodes can fail and become a permanent short circuit.

Thyristor surge protection devices (TSPDs):

These special solid-state semiconductors have similarities to GDTs in guarding against sudden voltage spikes, but they react quicker. When activated, their low clamping voltage (similar to GDTs’ spark gaps becoming ionized and conducting) lets surge currents pass with minimal heat produced within the device.

Carbon block spark gap overvoltage suppressor:

Spark gaps have been used for a long time to safeguard telecom equipment from power surges. Carbon block surge suppressors, known as GDTs, have two electrodes, but they’re exposed to air and affected by the weather. The gap between the carbon rod electrodes determines when the spark sends unwanted spikes to the ground. These components generate sparks during operation, so they can’t be used in places where explosions could happen.

Series Mode (SM) surge suppressors:

These work in a unique way compared to the mentioned components because they don’t use materials that wear out from repeated surges. Series suppressors, as the name suggests, don’t redirect surge currents or voltage. Instead, they use combinations of inductors, capacitors, and resistors to suppress these surges. These parts slow down the energy spikes, acting like a filter to make the output safe for the load in terms of voltage and current.

Series suppressors (SMs) are often larger and heavier compared to parallel components that divert load. But, they last longer when correctly installed. The catch is that installation requires stopping the power supply temporarily to put them in series.

Protecting Cell Towers from Lightning Strikes with Surge Protection Devices

For cell tower systems to stay connected, the surge protection devices (SPDs) need to meet strict standards for handling electrical surges, particularly in terms of the highest test current from lightning and the maximum surge discharge. These devices have to redirect or soak up various surges caused by lightning consistently, without breaking down. This reliability reduces the need for maintenance, repairs, and extra parts.

Lightning and Surge Protection for Mobile Radio Systems

Mobile radio sites face the risk of damage due to lightning and surges, which can harm the power supply and availability. To ensure the protection of radio transmission technology, LSP assists customers in planning network infrastructure. Following the lightning protection zone concept DIN EN 62305, LSP customizes protection elements from its product range as needed.

Conventional Mobile Radio System

Typical mobile radio setups use corrugated coaxial cables to transmit signals from the antenna to the ground-based radio base station (RBS). The entire radio transmission technology is situated in this base station. During a lightning strike, there can be lightning currents on the shield of these coaxial cables.

To ensure the best protection, surge protectors for coaxial cables should be installed on both the mast and the base station. Moreover, the base station contains secondary systems like cooling or emergency power supply, which might also need extra surge protection. For safeguarding the base station’s AC power supply, AC combined arresters of type 1+2+3 are ideal.

Mobile Radio System With Remote Radio Head (RRH)

In mobile radio systems using remote radio head systems (RRH), the radio technology is placed close to the antennas on the mast. This allows generating and sending the RF signal directly from the antenna, preserving its strength. The signal from RRHs to the base station travels through a loss-free fiber optic link. This minimizes signal loss, enhancing transmission quality.

RRHs receive DC voltage directly on the mast. To safeguard delicate electronics, type 1+2 DC combined arresters are set up at RRHs and the transition to the base station. Moreover, this setup reduces cooling expenses and needed space in the base station. The AC power supply protection for the base station remains through type 1+2+3 AC combined arresters.

Surge Protection For Mobile Radio Systems On Buildings (RRH)

Many of the mobile radio systems mentioned earlier are set up on leased rooftop areas, sharing the building’s existing infrastructure. This is particularly common in inner cities where space is limited. If an external lightning protection system exists, the mobile radio system is incorporated into that protection plan. In this scenario, type 1+2+3 combined arresters are put in at zone transitions, like where the building is connected.

Inside the building, type 2 or type 2+3 surge arresters complete the protection strategy. Depending on whether signal transmission to the antenna happens via coaxial cables or remote radio head (RRH) systems, suitable lightning and surge arresters are used. Below is an example of a building equipped with RRH technology.

Surge protection of Telecommunications Systems

A data center processes a variety of information from different network elements and locations. This includes data from cell stations and fixed-line network nodes, which handle both voice and data communication. If a telecommunications provider’s data center experiences a breakdown, it can have significant effects. A large number of customers will be impacted by any such failure.

To address this challenge, suitable lightning and surge protection measures are set up at important points along the power supply route, alongside the redundant power supply structure. This helps ensure the operation of cellular communication and fixed-line networks remains uninterrupted. We will now delve into specific sensitive locations that benefit from the installation of lightning and surge protective devices.

Feed-in Surge Protection

For safeguarding the energy provider’s entry point into the data center, a type 1+2 combined lightning current and surge arrester is put in place. This device can effectively manage even strong lightning currents of up to 100 kA, directing them safely to the ground. Protecting the supply is vital, which is why the surge protective device (SPD) is also monitored using ImpulseCheck. This surge protection assistance system identifies any previous harm to the SPDs and informs the control room about the condition of the protective devices.

Main distribution Surge Protection

The cables from the energy supply and the backup power connect at the main distribution. Because strong lightning currents and overvoltages can occur in this part of the system, a compact device combination (type 1+2 special combined lightning current and surge arrester) is used for lightning and surge protection. ImpulseCheck is also utilized to monitor the condition of the surge protective device (SPD) at this critical supply point.

Emergency Power Supply Surge Protection

If the main power supply unexpectedly fails, the backup power supply takes over. A big battery storage system covers the gap until the built-in diesel generator is up and running, which happens automatically. This backup power supply is also shielded against overvoltages.

In this specific situation, even though lightning current can’t directly affect the generator’s sections, there’s a chance of partial lightning currents in that zone. Switching from regular to emergency power might also lead to surge voltage connections. To reduce this risk, a type 1+2 surge protective device (SPD) is employed.

Server Room Surge Protection

The server room is the central space in every data center. If a server breaks down, the remote signaling network will also stop working. Since the servers in this room manage both cell and fixed-line network communication, they must be guarded against overvoltages. Servers usually use 48 V DC voltage. The power lines going into the server rooms are defended using type 2 surge protection designed for DC applications.

Air Conditioning Surge Protection

Another crucial part of the data center is the air conditioning system. If the air conditioning malfunctions, the temperature in server rooms might rise significantly. This could lead to servers shutting down or, in the worst case, certain server racks failing due to overheating.

Here, type 2 surge protection prevents problems caused by overvoltages. These type 2 devices handle overvoltages up to a maximum surge current of 40 kA. They have a highest voltage protection level of 1.5 kV. The surge protective devices come in one to three phase options, depending on the design of the climate control power supply.

Brief summary

Critical infrastructure typically includes important assets or systems that are crucial for economic, social, or business operations. If any of these functions fail or have issues, it can greatly affect people’s well-being. To make sure services in cell communication and fixed-line networks stay accessible, the given example highlights the need to consider various installations.

Cell Site Surge Protection Explained

Cell sites are essential for communication infrastructure and need to be shielded from power surges caused by lightning hits.

A major concern for telecom operators is towers going offline due to lightning strikes, which often target the tallest structures in a region. These towers are critical because they must offer strong connectivity to ground-level users.

When lightning strikes a cell tower’s top, it damages equipment like receivers, antennas, and remote-radio heads placed up there. Moreover, this equipment connects to gear at the tower’s bottom responsible for sending signals across the network. The resultant surge from a lightning strike also harms equipment in the tower’s base station.

Power surges travel along the cables connecting the tower’s top and bottom, affecting delicate equipment at both ends.

To prevent further damage, industrial surge protection can be placed strategically to divert surges away from sensitive gear, limiting the impact area.

By integrating surge protection devices into wireless cell sites, operators can reduce downtime and repair expenses during lightning incidents.

This boosts network functionality for customers and enhances the companies’ profitability. The installation of surge protection devices within cell sites is a beneficial move for everyone involved.

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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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