Selection and use of detectors in perimeter security

When considering the requirement of perimeter protection for a particular site, the relevant user or design unit will encounter a choice of detector type.

At present, the sensors that can be used for perimeter detection on the market mainly include the following categories:
(1) Active infrared beam detector.
(2) Microwave radiation detector.
(3) Doppler microwave detector.
(4) Vibration detection sensor.
(5) Proximity magnetic field sensor.

The magnetic field detector is divided into visible (such as electrostatic induction) and invisible (such as buried RF radio frequency magnetic field and buried pressure detector).

Due to their different applicability, price ratio and performance, the above sensors can be left to the security system designer with a lot of options, and also make it possible for a specific site solution to be optimized.

In order to expound the above points conveniently, I will explain the security system of the physical protection of a nuclear power plant below:

The physical protection of nuclear power plants is mainly divided into the following two parts:

(1) The perimeter protection of the overall facility of the nuclear power plant consists of two fences

In Fig. 1, the fence a is composed of multiple wires of YAEL pressure sensor with intrusion detection function. The wires are horizontal, with an interval of 10 to 15 cm, and are densely spaced. The fence is provided with a detector every 50 meters. Any climbing or shearing intrusion on the barbed wire can be detected by the detector and converted into a corresponding electrical signal. The signal is transmitted to a signal processor configured one-to-one with the detector. The processor based on microprocessor technology, through the logical analysis of the signal, and then give RS-485 serial communication alarm or a simple switch normally closed contact alarm. The power supply of the whole system is 12VDC.
Using this detector, a closed perimeter alarm system is formed at the periphery of the nuclear power plant. Of course, the corresponding access control system should also be used at the entrance and exit of the nuclear power plant, thereby forming a perimeter alarm system without gaps.

(2) In order to ensure the safety of nuclear power facilities, a microwave radiation system is adopted between two fences 6 meters wide

The system sets up a microwave transmitter / receiver every 60 meters between the two fences.

The design concept of the system is: when there is an intrusion, the a-layer fence can generally give an alarm at the first time. If it crosses the first-layer fence, the system also has a second-layer microwave detection and alarm system. The b-layer fence does not have an alarm function. General physical fence.

By using a double-layer alarm system, the alarm detection rate of the system can be greatly improved, and a site with a high security level such as a nuclear power plant can be ensured under relatively safe protection monitoring.

The microwave receiver can also give a normally closed switch alarm and RS485 serial alarm in the alarm state.

In some blind areas, the system uses Doppler microwave detectors to cover small areas.

The alarm signals of all on-site detectors are introduced into the central processing center of the central monitoring center. Of course, the entire large-scale security system also needs to have CCTV video surveillance image review, so that the personnel on duty at the monitoring center can monitor the entire site 24 hours a day .

The above simple description is just a perimeter protection scheme for a specific site. For different security levels, different site appearances, installation sites, and customer budgets, by using different detectors, we can always provide customers with more satisfactory Program.