The main and most effective measure for protection of structures against
physical damage is considered to be the Lightning Protection System
(LPS). It usually consists of both external and internal lightning
protection systems.
An external LPS is intended to:
-
Intercept
a direct lightning flash to the structure (with an air-termination
system):
-
conduct
the lightning current safely towards earth (using a down-conductor
system):
-
disperse
the lightning current into the earth (using an earth-termination
system).
Main
protection measures against injury to living beings due to touch and
step voltages are intended to :
-
Reduce the dangerous current flowing through bodies by insulating
exposed conductive parts, and/or by increasing the surface soil
resistivity.
-
Reduce the occurrence of dangerous touch and step voltages by
physical restrictions and/or warning notices
The
type and location of an LPS should be carefully considered in the
initial design of a new structure, thereby enabling maximum advantage
to be taken of the electrically conductive parts of the structure.
By doing so, design and construction of an integrated installation
is made easier, the overall aesthetic aspects can be improved, and
the effectiveness of the LPS can be increased at minimum cost and
effort
Access
to the ground and the proper use of foundation steelwork for the purpose
of forming an effective earth termination may well be impossible once
construction work on a site has commenced. Therefore, soil resistivity
and the nature of the earth should be considered at the earliest possible
stage of a project. This information is fundamental to the design
of the earth-termination system and influence the foundation design
work for the structure.
Regular consultation between LPS designers and installers, architects
and builders is essential in order to achieve the best result at minimum
cost.
If lightning protection is to be added to an existing structure, every
effort should be made to ensure that it conforms to the principles
of the standard. The design of the type and location of an LPS
should take into account the features of the exiting structure.
Click Here to View
Our Range Of External Lightning Protection
Devices
Even small over voltages can disable sensitive
electronic equipment, computer networks and computer-controlled production
systems in fractions of a second. For protection against over voltages
which can result from lightning or switching processes in electrical
supply networks, OBO offers a wide range of surge and lightning arresters
for the German and international markets. These include not only devices
to protect AC networks of various voltage levels, but also special
systems for data lines and telecommunication devices, and protective
modules for process measurement and control systems.
Electrical and electronic systems are subject
to damage from the Lightning Electro Magnetic Impulse (LEMP).
Therefore LEMP protection measures need to be provided to avoid failure
of internal systems.
Protection LEMP is based on the Lightning
Protection Zone (LPZ) concept: the volume containing systems
to be protected shall be divided into LPZ. These zones are theoretically
assigned volumes of space where the LEMP severity is compatible with
the withstand level of the internal systems enclosed.
Successive zones are characterized by significant changes in the LEMP
severity. The boundary of an LPZ is defined by the protection
measures employed.
Design of an LPMS (Lightning Protection Measures System)
LPMS can be designed for protection of equipment against surges and
electromagnetic fields.
-
an LPMS employing spatial shields and "coordinated SPD protection"
will protect against radiated magnetic fields and against conducted
surges. Cascaded spatial shields and coordinated SPDs can reduce magnetic field and surges to lower threat level
-
an LPMS employing a spatial shield of LPZ 1 and an SPD at the
entry of LPZ 1 can protect apparatus against the radiated
magnetic field and against conducted surges
Note 1 The protection would not be sufficient, if the magnetic field
remains too high (due to low shielding effectiveness of LPZ 1) or
if the surge magnitude remains too high (due to high voltage protection
level of the SPD and due to the induction effects onto wiring downstreams
of the SPD)
-
An LPMS created using shielded lines, combined with shielded equipment
enclosures, will protect against radiated magnetic fields.
The SPD at the entry of LPZ 1 will provide protection against
conducted surges. to achieve a lower threat
surge level, a special SPD may be required (e.g. additional coordinated
stages inside) to reach a sufficient low voltage protection level)
An LPMS created using a system of "coordinated SPD protection",
is only suitable to protect equipment which is insensitive to radiated
magnetic fields, since the SPDs will only provide protection against
conducted surges. a lower threat surge level
can be achieved using SPDs.
ALL OUR SPDs ARE AUTO-RESETTABLE TYPE. It means, once Surge is
conducted to earth, there is no manual intervention required to reset
them. they restore automatically.
Click Here to View Our Range
Of Internal Lightning Protection Devices
Site Survey, Recommendation, Selection, Installation and Commissioning
support of Both External and Internal Lightning and Surge Protection
Systems. As this is a new concept getting popularized in India, we
conduct many presentations, Seminars, Participating in Exhibitions,
writing articles in leading electrical, Telecom, and Instrumentation
Magazines, Also Involving Advertisement on various Applications.
