There’s no reason for sparks to fly in engineering – sound lighting protection, and keen earthing keeps everyone and their electronics safe.
To start, it’s important to note the damage lightning can cause, not just as a natural phenomenon, but as one observed in the human world.
This gives insight into why Earthing and Lightning protection are so important.
Lightning can cause deaths, injuries, damage, and significant costs and losses to businesses, buildings or the electrical systems associated with the built environment.
The global lightning flash rate is estimated to be in the range of 40 to 100 lightning flashes per second. Of these around 30% of flashes are cloud-to-ground flashes.
Power transmission and distribution lines around the world are often located in areas with high ground flash densities – and these lines are then susceptible to lightning-caused power interruptions.
This makes it an interesting area to study since the use of electronic devices that are considered sensitive to surges and interruptions has increased, coupled with the demand for a stable power supply.
In short, climate change. While lightning protection has long been part of electrical and electronic engineering curriculums – there’s a larger need for it to be driven home more effectively for engineers to better understand how the world of tomorrow may be impacted due to climate change.
According to the paper Project Management of Lightning Protection Innovative Design lightning protection is becoming more important because the climate has changed, and lightning occurs more frequently than ever before.
The paper notes that lightning accidents increased, but the adoption of new lightning protection devices and increased deployment of lightning arresters has been able to maintain supply and also protect devices that could have been susceptible due to the increase of lightning.
Statistics about the application of the system in an oil production plant, for instance, have shown that the system has improved the plant’s economic gains because lightning protection is considered in the microcosm of the plant. It also points to the fact that lighting protection and earthing are very important, not only for protection but to ensure economies stay afloat.
Earthing and Lightning protection are important for everyone that uses electrical equipment and that includes the large majority of the world.
Earthing, Lighting Arrestors and Surge Protection Devices are the leading devices that protect devices against current shock.
Here’s how these factor into lightning protection and earthing when we look at grounding (or earthing).
The importance of this is due to systems in any electrical network providing an alternative route for the electrical flows of leakages, or that accidents or shocks cannot cause any harm or failures.
Earthing is important in homes and big buildings, and earthing is required for any electrical and electronic device you find in a building.
Well, earthing works in tandem with Lightning Arrestors.
An Arrestor is a conductive device that grounds lighting quickly and then allows grounding to do its job. When lighting strikes a building for instance it will damage the structure of the building.
Then, lighting needs an easy path to discharge when the current is disrupted and discharges to the weakest point of a structure.
To avoid damage arresters are installed to provide a protection radius for a building.
If you enter a course with EIT with a unit or module focused on Earthing and Lighting Protection, students need to understand lightning.
Lightning is the sudden draining of charge built up in cloud systems. Lightning may occur between two cloud systems, within a single cloud system or between a cloud system and the ground.
Most lightning is within the cloud or between cloud systems. Only about 15% are cloud-to-ground discharges, also called ground flashes, these being responsible for the bulk of the damaging effects of lightning.
Cloud-to-cloud discharges can generate radio interference, often heard as clicks and bangs from nearby storms, or whistles and howls from storms on the other side of the planet. The discharges to the ground are far more destructive than the discharge between clouds.
This is because a direct lightning strike may involve a living being or other objects which are subjected to extremely high-magnitude short-duration current pulses that happen during the sudden transfer of charge from the cloud to the ground.
The incidence of lightning strikes at any given location depends on both atmospheric and geographical factors. It is usually associated with areas having convection rainfall. It requires the presence of high moisture levels in the air and high surface temperatures on the ground.
For example, the incidence of lightning is very high in Florida whereas colder locations such as Canada, where moisture levels in the atmosphere are equally high, are much less prone to lightning.
Since the lightning protection measures to be taken for an installation will depend on the probability of a lightning strike at that location, the frequency of lightning occurrence has been extensively studied and the results are published in the form of Annual Isoceraunic maps for different world regions.
These are contour maps, which show the mean annual thunderstorm days in the region involved. A thunderstorm day for this purpose is defined as one when thunder is heard at the point where it is measured.
This obviously cannot indicate whether it is a result of inter-cloud or cloud-to-ground discharge. It does not also show the frequency/number of instances or severity of cloud-to-ground flashes.
A lightning strike is primarily a series of current pulses (strokes) of very high magnitude. Being analogous to a current source, the magnitude of the current of a lightning discharge is not affected by the impedance of the path through which it flows.
In other words, assuming that the current path has an overall impedance Z, the effect of lightning discharge will be to cause a voltage rise across the path through which it flows; the more the impedance, the higher the voltage. It must be remembered that even a short length of copper or galvanized steel strip can offer substantial impedance, mainly as a result of the steep rise time of the lightning current wave and the inductance of the strip.
Some of this voltage appears across parts of the structure through which the discharge takes place. Part of it may appear in the layers of soil along which the discharge takes place. Especially in the case of a lightning stroke terminating directly on the ground, a substantial potential difference can develop in the form of equipotential concentric rings with the point of stroke as the centre. It, thus, puts the personnel and livestock who are in the vicinity at risk. Sometimes, such potentials can be transferred to points much farther away by metallic piping or other conducting parts running between these points.
As a result…
In assessing the risk, the following are the considerations for engineers to paint a picture of why buildings need proper earthing and lightning protection.
Type of loss due to lightning:
Losses due to lightning can be classified as:
The extent of loss will depend on the number of people normally present within a building, the type and importance of the service provided to the public, the value of contents in the building, and the possible loss of revenue as a result of damages sustained.
Lightning can result in loss due to the following basic causes:
Types of damage due to lightning strikes are:
A comprehensive lightning protection system must address the prevention of all three types of damages listed above.
While lightning protection of the structure itself addresses the prevention of damage due to direct strike, prevention of the indirect strike damage, such as failure of electrical and electronic equipment by overvoltage, will require the installation of various surge protective devices in power, control and signal circuits and also at their points of termination at the vulnerable equipment.
The type and extent of damage to a structure will depend on the following factors:
A lightning strike on a building or facility carries the following risks:
This also gives the role of maintenance engineers and technicians, who have a very important role in protecting structures and also ensuring that no lives are in danger.
Repairs involve the following:
The maintenance of a lightning protection installation is similar to that of any other electromechanical installation and broadly consists of the following activities:
In the case of lightning protection installations, the inspection normally involves:
Well, the first step is gaining ground and thorough knowledge of lightning protection and earthing.
For anyone working in the industry, a Professional Certificate of Competency in Earthing and Lightning Protection could assist in aligning with the latest standards and procedures.
The three-month Certificate of Competency course covers:
For students that want to know the industry better, and gain a practical understanding of lightning protection and earthing, a 52894WA Advanced Diploma of Applied Electrical Engineering (Renewable Energy) is a great option.
The 24-month diploma aims to equip students to adapt and evolve with the new technologies in the energy sector. Upon completion of this program, you will gain skills and knowledge in electrical engineering fundamentals, electrical machines, transformers and switchgear, power system protection, power quality, energy efficiency, renewable energy sources and generation, smart grids, distributed generation and energy management.
Course Benefits include:
Can you study more in-depth?
Of course! The pathway to becoming an electrical engineer is an exciting one. To find out how to complete a Bachelor’s degree here.
This is a helpful guide to show how this kind of engineer fits into lightning protection and earthing, and why it is so important.
