Instalasi Penangkal Petir
The installation of the LPS using ESE air terminals must follow the relevant
standards (NFC 17102, UNE 21186 or similar):
- The radius of protection offered by an ESE lightning conductor is related
to its height (h) relative to the area to be protected, to its triggering
advance and to the protection level. The following table shows the DAT
CONTROLER® PLUS radii of protection.
- The air terminal must be installed at least 2 meters higher than any other
element within its protected area.
- Each air terminal must be connected to the earthing using two
down-conductors that will preferably be placed on different
external walls of the structure.
- The down conductor should be installed such that its routing is as
straight as possible and takes the shortest path to earth without sharp
bends or upward sections. Care should also be taken to avoid crossing
or running conductors in close proximity to electrical cables.
- When external routing is impracticable, the down-conductor may be
internally routed inside an insulating non-flammable duct with a minimum
internal cross-sectional area of 2000mm2. The project manager must
also be aware of the reduced lightning protection system effectiveness,
maintenance difficulties, and the risks resulting from the entry of voltage
surges into structures. (” Instalasi Penangkal Petir “)
- The number of fixings is determined considering 3 clips per meter.
- Down-conductors should have a cross-section of at least
50mm². Since lightning current is impulsional, flat conductors
(tape) are preferable to round conductors because they have
a larger surface for the same amount of material. On another
side tin-plated copper is recommended due to its physical,
mechanical and electrical characteristics (conductivity,
malleability, corrosion resistance and so on).
- Down conductors should be protected by installing guard tubes up to a
height of 2m above ground level.
- The installation of a Lightning Event Counter over the guard tube is
recommended in order to perform the verification and maintenance
operations which are essential for any lightning protection system.
- The down-conductor must always be at least 3 meters from external gas
- Each down-conductor must have an earth termination system.
- Earth terminations should be located externally to the building.
- The connection with the earth termination system must be done directly
at the end of each down-conductor, using a device that allows the
disconnection of the earth electrode and should be placed inside an
inspection pit marked with the earth symbol.
- The resistance of the earth measured by conventional means
must be lower than 10Ω when separated from other conductive
elements. (” Instalasi Penangkal Petir “)
- The inductance of the earthing must be as low as possible. The
recommended arrangement is vertical electrodes forming a triangle with
a minimum total length of 6m. The vertical electrodes must be bonded
with a conductor buried 50cm deep and separated at a greater distance
than their length.
- The use of a soil conductivity improver is recommended in high resistivity
- All the earth termination systems should be bonded together and to the
general earth system of the building.
- It is recommended to use a spark gap to connect the lightning earth
termination system to the general earthing, as well as the lightning air
terminal mast to any aerials.
- All elements of the earth termination system must always be at least 5
meters from any buried metallic or electrical service.
Working basis and main materials
The functioning of Early Streamer Emission Air Terminals is based on the electric characteristics of lightning formation. Lightning initiates with a downconductor, propagating in any direction. Once it approaches a close proximity to objects on the earth surfaces any of them can be struck. The objective of an external lightning protection system is to control the lightning strike point and provide the lightning current with a path to earth avoiding damage to the structure.
The main feature of Early Streamer Emission (ESE) Air Terminals is the generation of the continuous upward leader before any other object within its protected area. The standards define this characteristic using a parameter called advance time (Δt):” Average gain in upward leader triggering compared with a reference point having the same geometry. It is obtained by laboratory tests, and is measured in microseconds.”
The advance time determines the protection radius of each air terminal. If the triggering occurs earlier, then the distance at which the downward leader is intercepted increases, thus avoiding a lightning strike in a wider area. The advance time must be measured in a High Voltage laboratory, following the test procedure described in the ESE lightning protection standards.
The components for a Lightning Protection System using ESE Air Terminals are as follows:
External Lightning Protection System
- One or more air terminals.
- Two or more down-conductors.
- An Earth Termination System.
Internal Lightning Protection System
- A correct surge protection installation (see Overvoltage Protection
- Other measures minimizing the destructive effects of lightning
(equipotential bonding, screening, etc.)