Lightning is a powerful atmospheric electrical discharge that can pose a great danger depending on where it strikes. Without proper protection and prevention, these discharges pose a risk to people, animals, buildings and electrical and electronic equipment, as well as causing environmental disasters. Although they cannot be prevented, there are storm detectors that issue the necessary alarms to take action to take preventive measures.
The implementation of lightning prevention and protection measures has continuously reduced the number of people killed or injured by lightning strikes. Preventive measures are temporary actions that are put in place when a lightning risk warning is received and are deactivated once the danger has passed. These measures, in addition to improving occupational risk prevention, help to protect assets and reduce costs. However, not all storm detection systems are the same: the implementation of Smart features, the number and technology used by the sensors or the remote operation by experts are clear differentiating elements that mark the efficiency of the alarms.
From the effectiveness of dual-sensor technology to why a prior study of the terrain should be carried out, these are the five most frequently answered questions by Aplicaciones Tecnológicas’ specialists on local thunderstorm detection.
1. What is the difference between measuring the electrostatic field and the electromagnetic field in storm detection?
Electrostatic field sensors measure the variation of the ambient electrostatic field, which is the only direct and unambiguous indicator of the real risk of a thunderstorm. Therefore, according to IEC 62793:2020, they are the only sensors that detect all phases of a thunderstorm, from its formation over the area to its dissipation. Thus, they issue the risk alarm with adequate lead time to take preventive actions.
Electromagnetic field-based storm detectors measure the electromagnetic radiation produced by lightning. In other words, they need a first discharge to issue a warning. Therefore, these systems are useful for the analysis of past events, but are not always suitable for preventive measures, such as when the first discharge occurs directly on the target. In this particular case, electromagnetic field-based detectors will not issue a hazard warning, whereas electrostatic field-based sensors will have issued a warning well in advance.
On the other hand, electromagnetic field-based detectors base their no-risk warning on a predetermined time after the last discharge. However, it is possible that the risk is still present and a discharge occurs immediately afterwards. The opposite may also be the case, i.e. the shutdown time may have been too long, because the storm has moved away or dissipated earlier.
In contrast, the objective measurement of the electrostatic field allows stopping only for as long as necessary, as the variations in the ambient electrostatic field correspond to the actual risk of a thunderstorm in the area.
2. How far away does lightning have to strike for a storm detection system to give a warning?
The ATSTORM® system has an electromagnetic field-based sensor as a complement to the electrostatic field sensor on which the lightning risk warnings are based. This electromagnetic field-based sensor makes it possible to monitor the approach of active thunderstorms up to a radius of 40 kilometres. In this way, the monitoring area is extended and a pre-alert status warning can be defined for distant active storms approaching the target to be protected.
However, according to IEC 62793:2020, the measurement of the electrostatic field is the only direct and unambiguous indicator of the actual risk of lightning strike before a discharge occurs. In the 20 km area, the ATSTORM® storm detection system measures the ambient electrostatic field, determining the risk based on this measurement and not on the distance at which lightning strikes have occurred. Distance is not a factor in determining the risk in the area to be protected.
However, before installing a storm detection system, it is essential to carry out a preliminary study of the location in order to offer a suitable solution.
3. Why are multiple detection units necessary?
With a single sensor we would have information from a single point, with a system based on the reading at specific points it is possible to obtain a valid alarm for the entire area to be protected.
The reading of environmental sensors, based both on electromagnetic field and electrostatic field, can be interfered by any external element outside the parameter to be measured. The installation of redundant detection units is necessary to minimise these interferences and increase the accuracy and reliability of the measurements. Furthermore, as in the case of the ATSTORM® storm detection system, the redundancy of units is used to improve the warning criteria in terms of both precision and accuracy.
Therefore, the installation strategy of the ATSTORM® system consists of multiple detection units, the number and location of which is determined according to the location to be protected considering its dimensions and the risk calculation. The redundancy of ATSTORM® detection units makes it possible to obtain a homogeneous alarm that is valid for the entire target area, thanks to the balanced auto-compensation of the values obtained, which guarantees exceptional accuracy.
4. Why is it necessary to carry out a preliminary study before installing a storm detection system?
the area to be protected in order to determine the number of sensors and their locations, which will depend on different factors such as:
- Dimensions of the area
- Infrastructures present
It is also necessary to know the necessary preventive actions to adapt the adjustment of the equipment, as well as the necessary warning systems.
5. Where should the sensors be installed?
The sensors of a storm detector should be installed in an elevated location, away from anything that may distort the electrostatic field.
If there are higher nearby elements, it is necessary to move away twice the difference in height. In case of installation in buildings, the corners of the building should be avoided.
Remotely operated sensors via IoT
In addition to dual sensor technology, the ATSTORM® expert local storm detection system from Aplicaciones Tecnológicas is operated remotely by experts via IoT (Internet of Things) and is part of the Smart Earthing and Lightning Solutions range.
By sending data to a centralised server, it allows alarm algorithms to be modified to improve alarm performance, cross-reference data with other sources to improve the system, adapt algorithms to changes that may occur at the site and monitor the status of equipment for predictive maintenance.
If you want to learn more about local storm detection and how ATSTORM® works, please contact us at the following link and download the free ebook Advanced lightning risk management.
You can also attend any of our storm detection webinars by clicking on the link below.