NEXO – FSD (Field Sensitive Device- ESE) Terminal NEXO – FSD (Field Sensitive Device- ESE) A super active wide area protection active lightning system is the only possible method to protect from direct lightning strikes. Because during the thunderstorm the lightning down-leader is approaching to ground, and the upward iron dissipation is created by any conductive surface. Nexo FSD lightning conductor is shaped by two Variable Impedance Units. One of them is connected to ground other at atmospheric potential.
During the thunderstorm produce great magnitude of the electric field and the Nexo FSD variable impedance units are separated by a very short distance, the difference of potential between the variable units create upward leader earlier during downward leader becomes considerable The streamer emission favours the upward leader formation, which will progress continuously till reaching the downward leader, forming then the discharge path and the Nexo FSD is the point where the upward leader was formed. It will be the receiver of the lightning strike. Nexo FSD Variable Impedance Unit working is regulated by the atmospheric field.
The principle of operation of an Nexo PSD terminal is to create an upward streamer earlier than conventional air terminals or other objects on the earth. Nexo PSD does this by collecting and storing ground charge during the initial phase of a thunderstorm development and emits strong and consistent upwards streamers earlier than conventional air terminals or any other objects on earth.
The triggering time AT (ps) is defined as the gain at the spark over instant obtained with an ESE terminal compared with a simple rod terminal exposed to the same conditions.
According to NF C 17-102, the triggering time instance gain △T is associated with a triggering time distance gain △L.
△L=V.△T where :
△L(m): gain in lead distanceof spark over distance.
V(m/µ): the average speed of the downward tracer.
△T(µ): gain in spark over time of the upward leader.
As a general rule for protection, the object to be protected shall be in the radius of protection of a lightning protection system whose electro magnetic characteristics are compatible with the capability of the object to withstand stress causing the damage (Physical damage, failure of electrical & electronic systems due to over – voltages)
Level I (D=20)
|H (m)||Nexo FSD HE||FSD 20 Rp||FSD 40 Rp||FSD 60 Rp|
|Level II (D=30)||2||11||15||28||35|
|Level III (D=45)||2||15||18||32||39|
|Level IV (D=60)||2||17||20||36||43|