Lightning Protection Systems

LIGHTNING ARRESTATION & PROTECTION

Lightning is one of nature's most powerful and destructive phenomena

Lightning discharges contain awesome amounts of electrical energy and have been measured from several thousand amps to over 200,000 amps - enough to light half a million 100 watt bulbs! Even though a lightning discharge is of a very short duration (typically 200 microseconds) it is a very real cause of damage and destruction.

The effects of a direct strike are obvious and immediately apparent - buildings damaged, trees blown apart, personal injuries and even death. However, the secondary effects of lightning - the short duration, high voltage spikes called transient overvoltages can, and do, cause equally catastrophic, if less visually obvious, damage to the electronic systems inside a building.

LIGHTNING PROTECTION

Lightning is a giant spark of electricity in the atmosphere or between the atmosphere and the ground. In the initial stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground; however, when the differences in charges become too great, this insulating capacity of the air breaks down and there is a rapid discharge of electricity that we know as lightning.

A lightning protection unit provides a specified path or redirection of the lightning potential to less volatile locations.

SURGE PROTECTION

A surge protector is an appliance or device designed to protect electrical devices from voltage spikes. A surge protector attempts to limit the voltage supplied to an electric device by either blocking or shorting to ground any unwanted voltages above a safe threshold.

The terms surge protection device (SPD) and transient voltage surge suppressor (TVSS) are used to describe electrical devices typically installed in power distribution panels, process control systems, communications systems, and other heavy-duty industrial systems, for the purpose of protecting against electrical surges and spikes, caused by lightning

TYPES OF LIGHTNING PROTECTION SYSTEM

There are four general types of commercially available lightning protection systems, as follows:

• Conventional air terminal systems – designed to collect strikes
• Early streamer emitting air terminal systems – designed to collect strikes
• Charge transfer systems – streamer delaying arrays that are designed to prevent all possible lightning strike collection
• Hybrid system - streamer delaying air terminals that collect strikes only when charge transfer capacity is exceeded by dissipation requirements.