Strictly speaking, the monitoring system needs to install lightning protection equipment, whether it is indoor monitoring or outdoor monitoring, but due to the different economic conditions of each industry and even each unit and the different security levels of monitoring requirements, the integration of lightning protection equipment depends on the situation Different, usually need to consider the following lightning protection factors:

1. Lightning protection of front-end equipment

The front-end equipment is installed in both outdoor and indoor situations. The equipment installed indoors is generally not subject to direct lightning strikes, but it should be considered to prevent lightning overvoltage from damaging the equipment, while outdoor equipment must also be considered to prevent direct lightning strikes, such as front-end equipment The camera should be placed within the effective protection range of the lightning receptor (lightning rod or other lightning conductor). To prevent electromagnetic induction, the power cable and signal cable of the camera along the pole should be shielded through the metal tube. The signal line has a long transmission distance and a low withstand voltage level. It is easy to induce lightning current and damage the device. In order to transfer the lightning current from the signal transmission line to the ground, the signal overvoltage protector must respond quickly. When designing the protection of the signal transmission line, the signal must be considered Parameters such as transmission rate, signal level, starting voltage and lightning flux.

2. Lightning protection of transmission lines

The transmission line of the monitoring system is mainly the power line of the transmission signal line. The control signal transmission line and the alarm signal transmission line generally use copper core shielded flexible wire, which is erected (or laid) between the front end and the terminal. From the perspective of lightning protection, the direct-buried laying method has the best protection effect, the overhead line is most vulnerable to lightning strikes, and is destructive and has a wide range. To avoid damage to the head and tail end equipment, the overhead line should be done on each pole For grounding, the suspension wire of the overhead cable and the metal pipe in the line should be grounded. The signal source and power supply at the input of the intermediate amplifier should be connected to suitable lightning arresters respectively.

3. Lightning protection of terminal equipment

In the monitoring system, the lightning protection of the monitoring room is the most important. It should be carried out from the aspects of direct lightning protection, lightning wave intrusion, equipotential connection and surge protection. Since 80% of the high lightning strike potential is invaded from the power cord, in order to ensure the safety of the equipment, a three-level lightning protection should be set on the general power supply. Before the video transmission line, signal control line and intrusion alarm signal line enter the front-end equipment or enter the center console, corresponding lightning protection devices should be installed.