The perimeter alarm system employs advanced technologies such as microwave, active infrared, and electronic fences to create a protective barrier—visible or invisible—at the boundary of the protected area. When an unauthorized intrusion occurs across this boundary, the corresponding zone detector triggers an alarm signal, which is then transmitted to the central alarm control unit. Along with sound and light warnings, the system also identifies the exact location of the incident. In addition, it can integrate with perimeter electronic screens, surveillance cameras, access control systems, and even high-intensity lighting for enhanced security response.
In recent years, perimeter defense systems have become a fundamental and essential part of modern security infrastructure. These systems are widely deployed not only in high-security environments like military facilities, barracks, airports, ports, and government buildings but also in residential communities. The demand for such systems has been growing rapidly, driven by increasing concerns over theft and vandalism. One common threat is cable theft, which poses a serious risk to power and communication networks.
Several common anti-cable theft technologies are currently in use:
1. **Power Carrier Communication Monitoring System**
This method leverages the concept of power carrier communication, which combines electrical and communication technologies. The system transmits a detection carrier signal along the monitored cable, and the monitoring center receives this signal. If the cable is cut or tampered with, the signal transmission is interrupted. When the system fails to receive the signal, it automatically triggers an alarm. This technique is widely adopted due to its ease of installation, concealment, and broad coverage (often several kilometers). However, it cannot prevent theft in real time, nor does it support video evidence collection. Additionally, integration with other systems remains a challenge.
2. **Capacitance Detection and Monitoring System**
This method uses a pair of empty cables connected at one end and linked to an oscillator at the other. Under normal operation, the oscillator remains inactive. However, if the cable is cut, the open end acts as a capacitor, causing the oscillator to generate a signal and trigger an alarm. The frequency of the output signal changes depending on how the cable is disconnected. This approach provides a simple yet effective way to detect cable tampering.
3. **Current Detection Monitoring System**
This system monitors the presence of current in the cable loop to determine the integrity of the system. If no current is detected, the system activates an alarm. However, this method is ineffective for voltage-based systems where there is no current, such as in subway tunnels or road tunnel ventilation cables. Moreover, the system only triggers an alarm when all branches of the circuit are cut, which means that partial damage may go undetected, posing potential risks.
302 Slot Type Thread Insert,302 Self Tapping Threaded Inserts,302 Stainless Steel Inner Thread Inserts,302 Self-Tapping Threaded Inserts
Shenyang Helisert Technology Co., Ltd , https://www.helisert.com