In Article " 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.
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:
2- Step potential:
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
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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
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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.
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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.
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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.
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