The development trend and anti-theft technology of theft of lighting cables

1 Background

1.1 Current status of stolen lighting cables

In recent years, the theft of lighting cables has become increasingly rampant. According to the online survey, the statistical data of cable theft losses reported by various cities over the years are shown in Table 1. It can be seen that the theft of lighting cables has caused huge economic losses to the country.

1.2 Social hazards caused by the theft of lighting cables

In addition to direct economic losses, the theft of lighting cables also brings great social harm to urban security.

(1) Public security and traffic safety are affected: Street lights are blacked out on a large scale, and cars will encounter darkness on average every few minutes. More than 90% of these blackouts are caused by stolen cables. When the street lights are not on, the probability of potential traffic accidents and thefts will increase, and the resulting social security problems are also emerging.

(2) Life safety is threatened: the cut of the street lamp cable and many exposed wire ends are live. If a passerby accidentally steps on or touches these wire ends, the possibility of electric shock is extremely high. In severe cases, it may even cause electric shock. .

(3) Self-safety is threatened: In addition to threatening the personal safety of residents, burglars may also be electrocuted and die during the theft process. Theft of transformer equipment and high-voltage wires has resulted in many cases of casualties.

1.3 Development trend of theft of lighting cables

In recent years, due to the price increase of non-ferrous metals, the scale of cities has expanded, the number of migrants has increased, and the theft of lighting cables has accelerated. According to statistical data, the total loss due to the theft of street lamp cables in Hangzhou in 2003 was 800,000 yuan, in 2004 it was 2.88 million yuan, and in 2005 the direct loss due to cable theft was as high as 5 million yuan. The trend of stolen lighting cables is shown in Figure 1. It can be seen that the loss caused by cable theft increases by more than 30% every year, becoming a huge heart disease in the mind of every lighting manager.

1.4 Take appropriate technical measures without delay

At present, the situation of stolen urban street lighting cables continues to deteriorate, and the management departments are helpless. They must take corresponding technical measures and measures as soon as possible to stop the spread of this trend, and use lighting cable anti-theft alarm technology to conduct real-time real-time street lamp cables Monitoring, finding anomalies in time, reducing or even preventing losses caused by cable theft, is a better anti-theft solution.

  2 Current technology and particularity of lighting cable

At present, some domestic manufacturers have produced corresponding lighting cable alarm systems, trying to solve this problem. These products use power carrier communication or cable characteristics to detect theft. However, due to the following characteristics of lighting cables, these technologies either have a high false alarm rate or are unreliable.

(1) The lighting circuit is energized after turning on at night and turned off after turning off during the day, requiring anti-theft alarms 24/7.

(2) Tens of microfarads of compensation capacitors are connected in parallel to each light source of the street lamp cable. The signal strength of the traditional power carrier decreases exponentially with the distance, which makes the power carrier communication very unreliable;

(3) The "self-extinguishing" phenomenon will occur before the end of the life of the high-pressure sodium lamp (it has been on and off for a few minutes), resulting in unstable cable current

(4) The lighting cable is buried in the ground, and after a long period of work, it will be affected by rain and humidity, resulting in leakage

(5) The failure of the lighting equipment itself often leads to local extinction, and the current changes greatly, and it is difficult to distinguish whether the cable is stolen or extinguished according to the current.

3 A new anti-theft technology for lighting cables

In order to solve these problems, we have designed a new lighting cable anti-theft alarm system. It is a combination of traditional anti-theft technology, wireless alarm technology, power electronics technology, computer data processing technology, multimedia technology and cable detection technology. Not only has the alarm function, but also has the line status detection function, the false alarm rate is extremely low, and at the same time, the remote alarm function is added.

The system is divided into two levels: monitoring front end and monitoring center.

Monitoring front end: includes several cable anti-theft hosts (referred to as "hosts"), and each host has several cable anti-theft terminals (referred to as "ends"). The host is set at the front end of the monitoring, and there is a wireless communication unit (the default is GSM communication). The host is connected to the low-voltage outlet of the power cable, and the number of terminals is determined by the number of outlets on the low-voltage side. The terminal is connected to the monitoring terminal host through a power carrier (the distance is not more than 3000m), and the single-channel detector is connected to one of the low-voltage outlets to detect the condition of the line. In Figure 2 only one host and one end are drawn.

Monitoring center: composed of communication processing front-end computer, computer host and related software. The computer of the monitoring center collects the working status of each point through a wireless network (public network) to realize data recording and management, and statistics of the data. Once an abnormal situation is found, the fault can be located in time, and the current status can be reported to the relevant personnel. The management personnel can Actively query the monitoring front-end operation information anytime, anywhere. The alarm signal has different forms (light, sound, mobile phone SMS alarm), and can be reported actively or according to the preset scheme. At the same time, the monitoring center has the function of sending short messages. After setting up the mobile phone numbers of the staff on duty, they can send alarm messages to these numbers during the alarm so that the relevant personnel can rush to the scene in time.

4 Comparison of this system with other programs

This system has the function of anti-theft when the lights are turned on and off. The comparison between this technology and existing domestic technologies is shown in Table 2 and Table 3. It can be seen from the table that this solution has the characteristics of moderate cost, high accuracy and low false alarm rate.

    5 Conclusion

The system has been tried in lighting and functional lighting systems. It has successfully issued a cable stolen alarm signal many times. After the staff arrived at the scene, they stopped the thieves' theft in time and saved huge economic losses for the country.