Anti-theft detection method for road lamp cable

Abstract

The invention discloses an anti-theft detection method for road lamp cables. The method comprises the following steps: accessing a variable frequency current source connected with a reactor, a fixed resistor and a rotary switch in series between a neutral point of a road lamp transformer and a three-phase low voltage busbar; changing injected signal frequency of the current source, measuring current and voltage output from the current source, finding out resonance frequency of a single-phase road lamp circuit, and measuring the number of road lamps and total equivalent capacitance of road lamps connected with the measured road lamp circuit; judging the circuit cable to be stolen if the number of measured road lamps is unequal to the number of actual road lamps, locating the stolen road lamp cable, and sending alarm signals. The method is not affected by transformer type or circuit length, can help accurately determine the position of the stolen cable without adding equipment at ends of the cable, has the advantages of being safe, fast and widely applicable, and completely solves the problem of disconnection alarming for circuit cables which are stolen in a shutdown period of road lamp systems.

Description

technical field [0001] The invention relates to an anti-theft detection method for a street lamp cable, in particular to an anti-theft detection method for a street lamp cable when the street lamp system is turned off. Background technique [0002] At present, there are three main anti-theft methods for street lamp cables in China: leakage current measurement method, voltage and current detection method and power carrier method. [0003] The literature [Cao Bin, Analysis on the Application of Cable Anti-theft Alarm Technology, Industrial Control Computer, 2009, 22 (5)] proposed the method of measuring leakage current, which creates an artificial leakage between the end of the cable and the earth, and detects it in the switch box. This leakage current, once the cable is stolen and cut off, the leakage current will be significantly reduced, and it can be judged whether the cable has been stolen and cut by the magnitude of the leakage current; however, due to the influence of t...

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Problems solved by technology

For this reason, the document [Zhang Neng, based on power line carrier low-voltage cable anti-theft scheme, electronic testing, 2009, 45 (6)] proposed a power carrier method, which transmits a power carrier signal at the head end of the cable, and installs a power carrier receiving device at the end of the cable. If the power carrier device cannot receive the power carrier signal, it is considered that the cable has been stolen and cut off; this method needs to install a carrier receiving device at the end of the line, which is expensive, and is affected by the capacitance of the street lamp and the cable, the carrier signal attenuation is large, and it is difficult to use for long-term Anti-theft detection of cables

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