Lightning protection for video surveillance system
Dated on July 23, 2011, Lightning strikers damaged the signal lighter and made two high-speed trains rear-end accident, 40 people death, hundreds injured.
In security field, most of equipment are installed outside for video surveillance system and perimeter security system. Thunder lightning frequently happen in summer season, there is great potential for video surveillance systems that damaged by thunder lightning. The result would be destroying the equipment and lost the money; also let the system can not work. For the safety of video surveillance system and keep the surveillance working properly, adopts effective thunder lightning protection, firstly should know the major reason of surveillance system damaged by thunder lightning and the possibility of access sources, especially for the damaged surveillance equipment. On the basis of analysis damage reason, choose and install correct thunder lightning protection equipment for surveillance system, research the BNC cable and power cable laying design, shield and connect to ground method...etc, to improve the capability of anti-lightning for the surveillance system. Video surveillance systems consist of front-end equipment, transmission equipment, terminal equipment, and Video Surveillance camera's anti-thunder lightning protection is the key factor for the whole anti-thunder lightning protection design.
Thunder Lightning Protection 4 steps:
Firstly, front-end equipment- video surveillance camera should be installed in the effective area of lightning rod; In addition, prevent the lightning invasion via the cables to front-end equipment, so the camera should install suitable lightning arrester (Anti-surge device).
Secondly, In the summer thunder raining days, signal transmission should adopt shield layer cable or cable go through the steel tube, also prevent Electromagnetic interference and electromagnetic induction are effective; For the terminal equipment, due to 80% lightning high potential is coming from power supply, so the video transmission cable, control cable, alarm input cables need to add thunder lighting protection device before connect to front-end equipment or to central surveillance station.
Application told us that using lightning arrester should be in high priority for whole thunder lighting protection layout.
Thunder Lightning Protection for surveillance central room is important.
People often neglect the surveillance central room for the thunder lightning protection, lightning protection for central room is the last procedure for the whole protection design. Video surveillance system through signal transmitter to receiver, signal transmit from outside to inside will bring the threat, so surveillance central room building should be with lightning rod, Lightning protection zone or lightning protection net. All the buildings should be set with Grading ring, all the down-conductors and metal material constructs and objects should be connect with grading ring.
From interview we get the clear idea that above stated thunder lightning protection solution are for the downward lightning strokes. Direct lightning is inevitable, An lightning safety analysis should be done before begin the surveillance project, especially for outside project.