Created by: Glen Zhu | Updated Date: June 20th, 2024
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. |
Insufficient assessment of lightning strike risk
(1) Assessment of lightning strike risk
– Complex evaluation process according to IEC61662
– 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
– 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
– Based on actual conditions
Conclusion of Lightning Risk Assessment
The previous board gives a quick indication of the risk but we can remind you that:
Relying solely on external lightning protection
Comprehensive lightning surge protection solution
Lack of understanding of direct lightning strikes
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:
The magnitude of the lightning current
International standards |
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| 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 |
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German standard | Iimp= 0.5 – 50 kA (10/350µs) |
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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 |
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Lightning protection component technology
Low-voltage surge protector surge protective device used in conjunction
– 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
Diversion Gap-type surge protective device products
3 major problems with traditional gap-type surge protective devices:
Rough protection – Protection against direct lightning strikes
Multi-layer graphite spark gap surge arrester
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
Solution
Communication room system solution
Communication base station system solution
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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