Network camera is a traditional camera and network technology combined to produce a new type of camera, is an important part of the monitoring system, it can be captured audio and video information transmitted to the user through the network, simple and convenient, has been widely used in education, medical, public **** cause and other fields. However, network cameras are installed in the open air, vulnerable to lightning strikes. So, how to do the network camera lightning protection? junhe electronic for you to do the following detailed analysis.
One, the network camera suffered a lightning strike causes analysis
(a) the main form of lightning attack network camera
The main form of lightning attack has a direct lightning and induction of lightning in two forms.
1. Ray is a direct lightning attack on the network camera, resulting in mechanical damage, this damage is the most serious, but this form is less likely to occur in reality
2. Induction of lightning
Because of the rapid changes in the lightning current, around which a strong electromagnetic field is generated, in the magnetic field of the network camera and its transmission lines induced by the strong electric potential, that is, electromagnetic induction; at the same time, in the magnetic field, the network camera and its transmission lines induced by the strong electric potential, that is, the magnetic field, the magnetic field, the magnetic field, the magnetic field and its transmission lines. Electromagnetic induction; at the same time, in the magnetic field of the network camera and transmission lines will also be induced with the lightning opposite charge, the formation of electrostatic induction. Induced lightning will cause great damage to the monitoring system, more common in reality, is the focus of protection.
(ii) network camera is the front-end equipment of the security monitoring system, belongs to the weak equipment, its sensitive components of the degree of tolerance is low, more unable to invoke the impact of lightning current. At the same time, this type of equipment are distributed in the outdoor open air, become an important object of lightning attack. Once struck by lightning, lightning current in the bad camera at the same time, along the power and signal transmission lines into the terminal system, to the monitoring center causing serious damage.
(C) network camera suffered a lightning strike is an important reason for the building security system has not yet established effective lightning protection measures, as follows:
1. in the lightning protection zone PLZOA no effective anti-directive lightning measures;
2. overhead transmission cables do not take a good anti-lightning surge intrusion measures;
3. network camera The front end is not installed signal surge protector or surge protector failure;
In summary, because the network camera is an important, inseparable part of security monitoring, so only a good monitoring system integrated lightning protection, in order to comprehensively, systematically and effectively solve the problem of lightning protection network cameras.
Three, the main measures to monitor the lightning system
(a) front-end acquisition equipment (including network cameras) lightning
1. Direct lightning protection measures
When the monitoring system's front-end acquisition equipment (including network cameras) is in the direct lightning protection zone (LPZOA) within the scope of the direct lightning protection measures should be taken, specific are Installation of lightning rods near the network camera, strictly in accordance with the radius of the rolling ball to calculate the scope of protection.
When the lightning rod is installed on the camera mounting pole, the steel pipe of the mounting pole can be used as a lead wire; when installed next to the camera, the distance between the two mounting poles should be greater than 3 meters.
2. The camera's connecting cable should take shielding measures, that is, the connecting cable should be laid through the steel pipe, and placed in the camera mounting pole steel pipe;
3. Camera metal mounting pole should be grounded, grounding resistance value is not greater than 4 Ω.
4. Network cameras should be selected to the front-end of the monitoring signal surge protector, the general situation for the monitoring, network, power supply, and the camera should be installed in the front-end of the camera. Three-in-one surge protector KS-E3/24/M, the product features are as follows:
Discharge current, the use of multi-level protection;
Built-in fast semiconductor protection devices, fast response speed, low residual voltage;
Excellent core components, excellent performance;
Energy-saving, environmentally friendly, easy installation, suitable for a variety of standard interface types;
Low insertion loss to ensure smooth lines;
Small standing wave coefficient, wide operating frequency range.
(B) monitoring system transmission cable lightning
Monitoring system transmission cable should be protected against lightning wave intrusion, take the cable with shielding effect, or the whole process of laying metal pipe threading. Shielding layer to be electrically penetrating, the first and last ends should be grounded or connected to the equipotential. Through the (LPZOA) area of the part, should be laid underground. If it is not possible to bury the ground, should be used to lay reinforced concrete poles overhead.
(C) monitoring system terminal equipment lightning protection
1. Shielding measures
Monitoring system terminal equipment for non-metallic enclosure, shielding measures should be taken, and the distance between the structural columns of the outer wall should not be less than 1 meter.
2. Equipotential connection
Terminal equipment to be taken to equipotential connection and grounding, and with the building's lightning grounding, protective grounding and other *** with the grounding system.
Electronic equipment exposed conductive parts, electronic systems, such as working ground should be connected through the conductor conductor equipotential connection network.
3. Reasonable wiring
Monitoring system to meet the requirements of the technical specifications of the integrated wiring.
In summary, the network camera lightning protection is a systematic and comprehensive lightning protection project, only comprehensively, in order to play a good protective role.