Use of A.G Surge Arrester in Information, Security and Automation Systems
Weak current systems are very important for the continuity of sustainable and uninterrupted operation in our daily life. CCTV camera, security and automation systems are the most frequently disabled systems in the face of lightning and mains strikes.
Do you know how often the MOBESE systems that monitor every point of a city fail?
Or that the automation system, which is the most strategic point of a factory or plant, can be disabled by a nanosecond pulse?
Economically very expensive systems are repeatedly disabled due to sudden overvoltage pulses, causing irreparable damage. In line with the data obtained from insurance companies, 80% of "Automation" system damages are the result of sudden overvoltage.
Leaving aside the economic dimension, when we evaluate the situation from the perspective of human life, facility and occupational safety, it must be ensured that these systems are sustainable. For this reason, we must protect data, coaxial and power lines with surge protectors.
After the lightning strike falls on our structure, 50% of it is damped in the ground, while the remaining 50% (approximately 100kA) is directed to the electronic systems inside the building.
In the emergence of the need for protection; unfortunately, there is an inversely proportional process with technological developments. The reason for this phenomenon is that the operating voltages of electronic devices, whose dimensions have become much smaller in parallel with technological developments, have also decreased to the order of smaller voltages.
According to the historical development sequence, it is known that during the transition from vacuum tube lamp devices to transistorised structure and integrated circuits, the operating voltages of the components used in the electronic cards of the devices decreased from 3000 VDC to 24 VDC and 5 VDC voltage values. Therefore, there is a transition towards electronic devices with increased sensitivity in the process.
Since there are no reductions or reductions in the voltages that occur depending on the type of load (inductive loads) at the time of switching electrical energy or in natural events, lightning discharge (200 kA) in parallel with this technological development, we have to equip our systems and equipment with the necessary protection elements to protect our systems and equipment from these negative effects.
While a camera system or an automation system operates with 24V and 48V voltage, all systems may be disabled due to sudden pulses at 20 times these values.
Data Centre is the brain of a facility. At a point where data is extremely important, it is a great loss if the entire system is disabled due to overvoltage pulses.
So how should we protect our systems?
Our known pulse characteristics; There are basically 2 types, 8/20 micro seconds and 10/350 micro seconds.
Selection and classification of internal lightning systems according to TS EN / IEC 62305 standards
► In the light of TS EN 62305 and IEC 61643 standards, Class (Type) 1,2,3 protection must be provided gradually at appropriate test values.
In all systems, energy, data and coaxial lines must be protected bidirectionally.
► While energy protections are connected in parallel to the system, data and coaxial protections shall be integrated into the system in series.
Protection of Camera Systems from Overvoltage
If we consider the camera system, at first, the panel from which the camera system is energised is usually single-phase systems. We must place products with Spark Gap technology with min 50 kA protection capacity in the camera main energy panel, which provides protection in Class 1 + 2 10/350 + 8/20 curves.
Sabit CCTV sistemlerini aşırı gerilim darbelerinden korunmak için yukarıdaki gibi C ve D sınıfı ürünler kullanılır.
Class C and D products are used as above to protect fixed CCTV systems from overvoltage pulses.
Our connection at this point min. 16 mm2 cross-section cable. Then we need to make sensitive energy protection in the camera end point box next to the camera. After energy protection, we must protect our camera by adapting the appropriate protection product to CAT or BNC inputs according to the type of camera and providing serial connection.
Protection in Automation Systems
In automation systems, we are obliged to select the appropriate product first, based on the system continuous voltage and by determining the "Upper Protection" level. There are sensitive energy protection classes as 5V, 12V, 24V, 48V, 230V. For example, if we are going to protect a PLC, a lightning barrier must be integrated in series before all lines entering the PLC. Here, the current characteristics of the products and the characteristics of the PLC are important in product selection.
Protection in Data Centres
In Data Centres, we must protect every CAT6 data line. According to the system structure, the product suitable for the transfer speed of the cables should be selected. Main energy panel, CAT5-6, RJ45 Lines, socket outlets, telephone switchboards must be protected.
The main energy panel, CAT5-6, RJ45 lines, socket outlets, telephone exchanges must be protected by internal lightning systems.
In addition, all card access systems, communication modules, DVR systems, image monitoring centres can be protected against overvoltage and lightning. What needs to be done is to select devices and methods suitable for the system structure. Expert engineer support is very important in this regard.