Why Should Lightning Protection Systems Be Grounded?

We assume most people have a basic understanding of lighting protection system grounding, however, you may not be clear about why we have to use the lightning protection system grounding in the lighting protection system engineering, you also may not understand the specific effect a lighting protection grounding system provides. Techwin will introduce these concepts to everyone in the below article:

1. Why should lighting protection system to be grounded

Grounding technology was originally introduced as protective measure to prevent electricity or electronic equipment from getting damaged during a lightning strike. The lightning protection system is designed to direct lightning current generated by lightning into the ground through a lightning rod, therefore protecting the building. At the same time, the lightning protection system grounding is also a kind of effective way to protect the personal safety. Personal safety can be affected when there is an event that causes the phase line (such as poor wire insulation, line aging, etc.) to touch the electrical/electronic equipment shell, that will cause a potentially dangerous condition for equipment shell.

Generated voltages, the resulting fault current will flow through PE line to the ground, therefore it will play a protective role. With the development of electronic communications within the digital domain to only consider the lightning protection and security in grounding system, it has been far from meeting the requirements for the future. Such as in communication system, the interconnection of signals between a large number of devices requires every equipment to have a standard "ground" as the reference point of the signal. And with complexity of electronic equipment, the signal frequency is getting higher and higher, therefore, in the lightning protection grounding system design, it needs to be given special attention to the problems of interference between signals and electromagnetic compatibility, otherwise, improper grounding will seriously affect the reliability and stability of the system operation. Recently, high-speed signals in the signal flow technology is also introduced within the concept of "Ground".

2. The common grounding symbols of lightning protection system

(1) PE,PGND,FG－Protection ground or cabinet

(2) BGND or DC-RETURN－Direct current－48V(+24V)Power supply（Battery）Backflow

(3) GND－Working ground

(4) DGND－Digital ground, also called logical ground, it is the zero potential of various switching (digital) signals.

(5) AGND－Analog ground, it is zero potential of various kinds of analog signal.

(6) LGND－Lightning protection sites

GND usually will be used as a voltage reference basis points in the circuit. From the electrical stand point, the lightning protection system GND is divided into the power supply ground and signal ground. PG is the abbreviation of Power Ground (Power location). The other one is Signal Ground. In fact they may be joined together. The two names are mainly to analyze of the circuit. Furthermore, there are also two kinds of "ground" that must be differentiated by different circuit forms: digital ground and analog ground.

Both the digital ground and analog ground have signal ground and power ground. Between the digital ground and analog ground, some circuits can be connected directly, and some circuits need to connected with an electric reactor, some circuits can not be connected

3. The definition of lightning protection system grouding

In the modern concept of lightning protection grounding system, for the line engineers, the meaning of this term usually is "The line voltage reference point"; for the system designers, it's usually a cabinet or rack; for the electrical engineer, it means green safety ground wire or earth ground. There is one more general definition, "Grounding is a low impedance channel which current returns back to its original place." Please kindly notice that the requirement is "Low impedance" and "Channel".

All above are related introduction to everyone about why lightning protection system needs to be grounded. If you want to learn more knowledge about lightning protection or any demands about lightning protection, please kindly consult with Techwin. We have many years of experience in the lightning protection industry, we are specialized manufacturer in lightning protection detecting, lightning protection engineering, intelligent lightning protection,etc., as well as the  relevant projects. We could provide the professional lightning protection solution plan for your reference.