Anti-theft detection method for road lamp cable

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.