What is the differences between passive and active lightning protection?

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WHAT IS THE DIFFERENCE BETWEEN PASSIVE AND ACTIVE LIGHTNING PROTECTION SYSTEMS?

We should understand the basics of Lightning strike formation first in order to understand properly these different systems and their mechanism fort he scope of Protection.

Clouds in the world atmosphere generally carry and consists of vast amount of humidious water particles in gas form. As well as any physical material has/may have electrical loads especially when these particles get potential loads generally by rubbing each others. This condition constantly loads these clouds with negative electrical charges. We are here talking about huge, namely hundreds of kA, and moreever free-spreading electrical charges in such states. Such amount of electrical charges cannot stand too much in cloud formations. Like any electrical charges, it also choose to discharge with opposite, positive in this example, location.

When these electrical fields find a proper positive opposite charge material it tends to discharge its load. We call this phenomenon as “Lightning”. In almost many occasions, direction of lightning is towards from clouds to ground, though, Lightning can also be derived from the ground to the air. It mostly up to intensity of the charges. In such discharge conditions, electrical field always choose the lest resistant path.

WHAT IS PASSIVE LIGHTNING PROTECTION SYSTEMS?

As the oldest and widest Lightning Protection systems, passive systems (conventional rods, simple rods, Franklin rods) have been used for almost 200 years around the world. Conventional rods is installed upon the buildings which is wanted to be protected from the heavy negative effects of the Lightning. However if conventional rods cannot be installed properly and at the right position their Protection capacity decreases as well. Because capability of such types of rods differs as to its mounting place height, rods direction, material, neighbour buildings and position as well.

For example; Lightning strikes can/may bypass a wrong installed conventional passive system to an antenna upon a building even if this passive Lightning rods was installed on a higher position than the antennta. In such condition we cannot talk about a full Protection area if passive systems is not properly and proffesionally installed on buildings.

Alternatively, building’s top surface can be covered with full copper or other passive systems to prevent avoiding any Lightning strikes discharges. This systems is generally called “mesh method” in Lightning Protection operations. This increases the Protection from unexpected damages and provides a better Protection.

Lightning rods generally do not avoid direct lightning strikes but instead “arrest” it. They kindly attract lightning strikes then transfers the energy discharges to the ground rather than to passing it to the building. Conventional lightning rods technically are able to re-route the direct lightning strikes away from the buildings. Becasue direct lightning strikes can/may cause huge fires and damages both to the buildings and people as well. 

 

 

WHAT IS ACTIVE LIGHTNING PROTECTION SYSTEMS?

There are different types of active and more advanced Lightning Protection systems. We will summarize some of them here;

1. Early Streamer Emission (ESE) Systems

Like conventional passive systems, Early Streamers also try to attract Lightning strikes to itself and conduct the immense charges to the ground. However, unlike passive systems ESEs also creates a inonized electrical fields in order to increase the probability of Lightning anticipation. An internal mechanism in ESEs allows these systems to generate positive IONs and empowers them to attract the negative heavy electrical loads in the clouds.

Thanks to these artificially generated inonized air around them, ESEs also able to create a safety dome within a particular Radius. This invisible dome is called as “Protection area”. ESEs commit to attract and conduct it to the ground any Lightning strike which can/may discharge in this area.

Protection areas of ESEs is determined by a parametre named as “advance time(DeltaT)” value. According to NFC 17-102/2011 ESE Standard, in order to be accepted as an ESE, an active Lightning Protection systems DeltaT value must be within the range of 10 to 60 microseconds. It means that an ESE can protect an area withing the range of up to 107 meters. See how protection areas are calculated here.

 

2. ​Charge Transfer Systems

Unlike ESEs, these systems promise to discourage the possible Lightning strikes rather than tring to attract it. Whereas ESEs produce an ionized air to create an artifical electrical field, CTSs try to dissolve such ionized area and transfer the possible Lightning strikes to a heavier electricity densed atmosphere.

In this sytems reduction of electricity zones is the main goal. Creation of these systems claim that basic mathematical and physics formulas tell us this is the best way to prevent the heavy negative effects of a Lightning strikes.

3. Dissipation Arraying

Like CTS, DA Systems also try to prevent Lightning strikes rather than anticipating them. Their core principle is creating a Lightning-free area upon the installed location by creating a negative electrical fields. As we examined in the Lightning strike formation, electrical charges in the clouds choose the lest resistant positive charged path to the ground. DA systems commit to dissolve the formation of this negative charged electrical fields and also Lightning strike discharge as well.

WHAT IS THE DIFFERENCE BETWEEN PASSIVE AND ACTIVE LIGHTNING PROTECTION SYSTEMS?

Breifly explaining, whereas passive Lightning protection systems only protects a small particular objects like building roof, chimneys and lighting poles provided that they are installed properly for intended position, active Lightning Protection systems try to increase their possibility to attract or discourage the Lightning strikes thanks to different technologies. Other particular differences can be summarised as below;

  • Passive systems are cheaper and easier to install. But if they are not installed properly their working performance can/may decrease up to 0%,
  • Perfomance of active systems are immensely higher than passive systems. Because these systems use different extra technologies, like ionization of the air in ESEs,
  • For active systems, grounding structure needs to be made better because the higher attraction possibility requires a more proper grounding systems as well,
  • Passive systems require less maintenance Operation

We as ORBITAL suggest

Passive systems to be used in;

  • Chimneys
  • Ligthing poles
  • Small house and depots
  • Tents
  • Water tanks

Active systems to be used in;

  • High-rise buildings
  • Nuclear and military facilities
  • Solar panels and wind turbines
  • Schools
  • Airports
  • Stations
  • Highways