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The high rise buildings lightning protection design has become a growing issue for two decades. Firstly, the designers and contractors are facing an increasing demand for high rise buildings, especially in the fast-developing countries: investors are requiring higher and higher structures, either to cope with the high price of land or for “prestige” and marketing purposes.
Introduction to Lightning System Design- Part One ', I listed all terms, abbreviations and Symbols used in lightning field and which will be used throughout Course EE-5: Lightning Protection Systems Design Calculations.Also, in Article ' Introduction to Lightning System Design- Part Two ', I answered the following questions:
- What is Lightning?
- What are the types of Lightning flashes?
- What is the shape of The Lightning Waveform?
- How Lightning strikes can affect the electrical and/or electronic systems of a building?
- What are the main effects of Lightning?
Today, I will explain the different Types of Lightning Protection Systems LPS.
What is the Lightning Protection Systems LPS?
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Why Using the Lightning Protection Systems LPS? Lightning protection is essential for the protection of humans, structures, contents within structures, Transmission lines, and electrical equipment by controlling a variety of risks resulting from thermal, mechanical, and electrical hazards of the lightning flash current. These risks can be categorized as follows:
1- Risk to persons (and animals) include:
2- Risk to structures & internal equipment include:
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Popular Risks Definitions 1- Side flash: All down-conductors have a resistance and, more importantly, inductance. During the lightning flash the rapid rate of current rise can cause the inductive voltage rise of the conductor to reach a magnitude where sufficient voltage exists for the conductor to flashover to a nearby conductive and earthed object. Side flashing can be controlled by:
The hazard is considered to be reduced to tolerable level if:
3- Touch potential:
The hazard is considered to be reduced to tolerable level if:
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What is The Effective Lightning Protection System? The effective lightning protection system which eliminates the above risks must be designed to:
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Types of Lightning Protection Systems LPS |
Types of Lightning Protection Systems LPS Lightning protection systems for buildings and installations may be divided into three principal types as follows:
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First: LPS for Protection for buildings and installations against direct strike by lightning This type of LPS protects the building from damage by direct strike lightning but doesn’t prevent the lightning striking the building. This type of LPS can be divided into:-
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1- Types of Conventional Lightning Protection System The Conventional Lightning Protection System includes (2) different types as follows:
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2- Types of Non-Conventional Lightning Protection System The Conventional Lightning Protection System includes (2) different types as follows: 1- Active Attraction LPS, which includes:
2- Active Prevention/Elimination LPS, which includes:
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Notes on different Types of Lightning Protection Systems LPS Each system’s design requires the following:
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1- Conventional Lightning Protection System |
Conventional Lightning Protection System Properly designed conventional lightning protection systems for ground-based structures serve to provide lightning attachment points and paths for the lightning current to follow from the attachment points into the ground without harm to the protected structure.
Such systems are basically composed of three elements:
The three system components must be electrically well connected. Notes:
Other names for Conventional Lightning Protection System: 1- Passive Neutral Systems: The Conventional Lightning Protection System is labeled as Passive Neutral Systems since the air terminal or strike termination devices themselves aren’t considered to be any more attractive or unattractive to the lightning stroke then the surrounding structure. They are positioned where they should be the first conductor in any path that the lightning strike takes to the structure. 2- Traditional Lightning protection systems: The Conventional Lightning Protection System is labeled as Traditional Lightning protection systems since these systems are the used ones in industry over 200 years ago. |
Types of Conventional Lightning Protection System The Conventional Lightning Protection System includes (2) different types as follows:
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1- Franklin Rod LPS Other names for this type of Conventional Lightning Protection System are:
Note: This system is generally limited to buildings less than 20 m high. |
2- Franklin/Faraday Cage LPS A faraday cage is an enclosure fixed to the outside of the building made of conductors laid out on a grid pattern to produce an external mish. If the building is steel formed, the job can be made considerably easier as the steel frame itself can be used as part of the cage, but air termination devices are needed if the upper external surface of the roof is not metal and continuous with the steel frame.
Advantages of The faraday cage LPS:
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In the next Article, I will explain the Conventional Lightning Protection System LPS Components. Please, keep following.
Course Lightning-1: Introduction to Lightning Protection System Design |