Lightning and Surge Protection for Communication Station

Lightning and Surge Protection for Communication Station

Created by: Glen Zhu | Updated Date: June 20th, 2024

Misconceptions about lightning and surge protection

  • “We have no way to deal with lightning strikes!”: WRONG!
  • “Lightning arrester is like a fuse!”: WRONG!
  • “As long as there is good grounding, it can prevent lightning.”: WRONG!
  • “I already have protection against lightning… I installed a lightning rod.”: WRONG!
  • “My equipment is already protected… I installed UPS.”: WRONG!
  • “A lightning arrester has been installed in my switch power supply…”: WRONG!

The lightning strike is a type of surge voltage

Surge voltage

Lightning strike

A direct hit of thunder

Inductive Thunder

Line surge

Fault surge

System switch overvoltage

Electromagnetic induction

Electromagnetic interference/radio frequency interference

Electrostatic induction

Human static electricity, frictional static electricity, etc.

Common Issues in Lightning Surge Protection for Communication Station

  • Inadequate lightning risk assessment
  • Solely relying on external lightning protection
  • Lack of understanding of direct lightning strikes
  • Insufficient graded protection

Insufficient assessment of lightning strike risk

(1) Assessment of lightning strike risk

  • Lightning strike risk can be assessed

          – Complex evaluation process according to IEC61662

  • Principles for assessing lightning strike risk:

          – Historical basis – statistics on thunderstorm days

          – Terrain survey – risk coefficient

           – Lightning attraction effect and power supply mode of communication towers

          – Sensitivity of equipment

          – Economic benefits

Definition and statistics of lightning strike intensity

Thunderstorm Day Nk:

Nk < 25 days – low risk area

Nk > 25 days – medium risk area

Nk > 40 days – high-risk area

Nk > 90 days – very high-risk area

Number of thunderstorms per square kilometer – year

Statistical analysis of lightning intensity

(2) Assessment of lightning strike risk

  • Determination of risk coefficient

          – Generally set at 1

          – Buildings located in the isolated wilderness are set at 2

          – Brick and wood structures with metal roofs are set at 1.7

          – Buildings located near rivers, lakes, slopes, areas with low soil resistivity in mountainous regions, exposed groundwater, hilltops, valley wind gaps, etc., as well as particularly humid buildings are set at 1.5

(3) Assessment of Lightning Strike Risk

  • The lightning induction effect of communication towers and the method of power supply input

          – Based on actual conditions

  • Sensitivity of equipment
  • Economic benefits

Conclusion of Lightning Risk Assessment

The previous board gives a quick indication of the risk but we can remind you that:

  • There is no situation where the risk is zero.
  • The cost of installing surge protective device is minimal for the entire system.
  • The cost of installing surge protective device is much lower than the economic benefits generated when it first provides protection.

Relying solely on external lightning protection

  • Lightning rods cannot achieve comprehensive protection
  • Power supply is the main path of lightning strikes and a key focus of protection
  • Other possible intrusion paths must also be considered

Comprehensive lightning surge protection solution

Lack of understanding of direct lightning strikes

  • Revision of national standards
  • Selection of lightning waveforms 8/20µs ≥ 10/350µs
  • Energy difference of about 20 times

Definition of lightning surge current waveform

Comparison chart of lightning currents

IEC 61312-1: Diversion of lightning protection equipotential systems

A complete lightning current is discharged through the following paths:

  • 50% of the lightning current is discharged into the ground
  • The other 50% is discharged through other paths
  • Approximately 10% is discharged from water pipes (metal)
  • Approximately 10% is discharged through gas pipelines (metal)
  • Approximately 10% is discharged through oil pipelines (metal)
  • Approximately 10% is discharged through power cables
  • At most, approximately 5% or a current of 5kA is discharged through communication cables

The magnitude of the lightning current

  • Class I 25 kA @ 10/350µs
  • Class II 20~40 kA @ 8/20µs
  • Class III 10~20 kV @ 1.2/50µs

International standards

 

 

 

 

Installation location >  Line entrance

Distribution end

Equipment end

International standard

Iimp= 20 kA (10/350 µs)

In= 20 kA (8/20µs)

Uoc = 10 kV (1,2/50µs)

In= 10 kA (8/20µs)

French standard

In > 20 kA

In > 5 kA

 

German standard

Iimp= 0.5 – 50 kA (10/350µs)

 

 

American Standard

10 kA

3 kA

500 A

British Standard

10 kA

3 kA

500 A

GB50057-94 (2000 Edition)

condition

B

C

D

Type I lightning protection building

12.5 kA

10/350µs

Maximum 20 kA 8/20µs

Maximum 10 kA Mixed Wave

Type II lightning protection building

10 kA

10/350µs

Maximum 20 kA 8/20µs

Maximum 10 kA Mixed Wave

Type III lightning protection building

10 kA

10/350µs

Maximum 20 kA 8/20µs

Maximum 10 kA Mixed Wave

YD/T 5098-2001

condition

Entrance B-level protection

Distribution panel C-level protection

City – Thunder Zone (or Less Thunder Zone)

Nominal 20 kA 8/20µs

15 kA rated surge protective device with voltage limiting function

City – multiple thunderstorm areas, strong thunderstorm areas

Nominal 40 kA 8/20µs

15 kA rated surge protective device with voltage limiting function

Suburbs or mountainous areas – danger zone

15 kA 10/350µs or nominal 60 kA 8/20µs

15 kA rated surge protective device with voltage limiting function

High mountains – minefields

25 kA 10/350µs or nominal 100 kA 8/20µs

15 kA rated surge protective device with voltage limiting function

Suggestion: Enter the building/station power supply B level. The protection should use 10/350µs waveform surge protective device.

Multi-level protection of power supply system

The level of withstand voltage for different devices is different

 

Electromechanical equipment

Common electronic equipment

Sensitive electronic equipment

Highly sensitive electronic devices

Protection Level Up

2,5 kV

1,8 kV

1,0 kV

0,5 kV

Example

  • Electric motor
  • Power distribution equipment
  • Electronic control equipment
  • Household appliances: washing machine, refrigerator
  • Office equipment: printer, microcomputer
  • Industrial control System, PLC
  • Hi-Fi, TV, VCD etc.
  • Computer system
  • Alarm system
  • Banking equipment
  • Home automation equipment
  • EDP
  • Remote control equipment
  • Alarm system
  • Professional electronic weighing equipment
  • Armarium
  • UPS

Lightning protection component technology

Low-voltage surge protector surge protective device used in conjunction

Solution for lightning protection of communication equipment room

  • The Importance of Survey and Design
  • Accurately Assessing Lightning Strike Risks
  • Considering Protection for Key Equipment
  • Defense Measures against Direct Lightning Strikes
  • How to Minimize the Impact on Power Supply Systems

          – Comprehensive Solutions for the Overall System

Principles and methods of lightning protection

How to choose a lightning surge protection device

surge protective device Installation Instructions

The installation of a lightning arrester needs to be carried out according to the requirements of IEC 61312.

Protected lines should not be parallelly protected with unprotected lines during wiring to avoid the reoccurrence of induction phenomena on the protected lines.

The length of the connecting wire of the lightning arrester should be less than 0.5m. Otherwise, an excessively long connecting wire may cause additional voltage drops, which could still damage the equipment.

The lightning arrester needs to be well connected to the grounding system. If the lightning arrester is installed inside the distribution box, a wire of 16 mm2 or more should be connected from the ground busbar of the distribution box to the grounding system.

Installation Principles of surge protective device

The voltage of the cable

Installation Principles

The right surge protection device (surge protective device) connection

If the length of the connecting line of the lightning arrester cannot be less than 0.5 meters due to on-site conditions, a V-shaped connection method is required.

Note that when using a V-shaped connection for the lightning arrester, the distance between the input and output lines should be separated as much as possible during deployment.

Selection of Isolation Switch

Switch component connected

The importance of the distance between equipment and surge protective device (surge protective device)

10/350µs Lightning surge current protection

  • External lightning protection measures – Conduction, grounding
  • Internal lightning protection measures – Conduction, diversion, grounding

Diversion Gap-type surge protective device products

3 major problems with traditional gap-type surge protective devices:

  • Arc leakage – combustion
  • Electrode oxidation – changes in conduction voltage
  • Continuity interruption – power supply short circuit

Rough protection – Protection against direct lightning strikes

Multi-layer graphite spark gap surge arrester

1. Extremely low starting arc voltage – limiting voltage is very low.
2. Reliable arc extinguishing technology – no power frequency follow-up current.
3. Flame-retardant sealed packaging – no need for isolated installation.
4. High-energy current capacity – used for direct lightning protection.
5. Ultra-long service life – saving usage costs.

B+C type power surge protector for small data centers

Main Technical Indicators

1. Surge protector component B+C level

2. Rated voltage (V) 220/380VAC

3. Maximum safe continuous operating voltage 385VAC, single phase

4. Rated power (kW) 20KW

5. Impulse current (10/350μs) 25kA per line

6. Nominal discharge current (8/20μs) per line100kA

7. Response time (ns) ≤25ns

8. Residual voltage at rated discharge current (100kk/8/20μs) ≤1.2kV

9. Operating temperature (℃) -40 to +80℃

10. Audible noise None when no alarm is triggered

11. Remote signaling contact(A/V): Dry contact type

12. Leakage current: ≤10uA, total leakage current

13. Frequency (Hz): 40~60Hz

14. Single/three-phase operation indicator Three-phase LED indicator

15. Surge counter function: 4-digit LED counter

16. Nominal conduction voltage(V): ≥2.2U (484V)

17. Highest conduction voltage(V): 647V

18. Applicable altitude (m): ≤10000 above sea level

19. Grounding requirement (Ω): ≤10Ω (Impact grounding resistance)

20. Wire cross-section(mm²): 16 to 35mm² (Multi-strand copper core wire)

21. Wiring method: Terminal block

22. Protection mode:3+1 or other methods

23. Connection method: Series connection

24. Lightning protection box status display Sound and light alarm, remote signaling interface

Complete product line

  • Overall solution
  • Full range of surge protectors (surge protective device)
  • All products are inspected by the Ministry of Information Industry’s Communication Product
  • Protection Performance Quality Supervision and Inspection Center and Beijing Lightning Protection Testing Center.

Solution

Communication room system solution

Communication base station system solution

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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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