Street lamp cable fault detection method

First, use the megohmmeter to detect

This method is a traditional street lamp cable fault detection method. The power supply radius of the street lamp line is generally between 0.4-0.6km, and the street lamp spacing is 30-40m. The whole line is like a trunk, and the load is relatively scattered. To detect the phase-to-phase and ground-to-ground insulation resistance of the cable, the street lamp load must be cut off first, then the intermediate point is disconnected, the phase-to-phase and ground-to-ground insulation tests are performed phase by step with a megger, and the troubleshooting method is used to determine the direction of the fault point. Since the method can only detect the gear distance of the fault point, the accurate position cannot be detected, and the cable break point is more, it needs to be re-clamped and restored, and the workload is large, which also adds a new fault hidden point to the future maintenance work. . Therefore, this method is now basically not used.

Second, with a clamp-type ammeter test

Because the existing street lamp power distribution cabinet is equipped with safety protection measures such as circuit breakers and fuses of corresponding capacity, the cable short circuit and leakage fault will not cause extensive damage to the cable. Generally, as long as the cable fault point is found, Cut and re-clamp the cable to continue using.

The principle of using a clamp-type ammeter to detect a street light cable is to instantaneously (2-3 seconds) power the street light cable by resuming the burnt fuse (Note: a short-term instantaneous current does not cause the street light cable to heat up rapidly, ie It will not cause new damage to the street lamp cable. According to the fault point to the power supply, the fault current is very large, and the current at the fault point is small. When the detected current value becomes normal, the current value is normal. The previous gear of the lamp position is where the fault point is. The order of detection is: first open the access door (or maintenance well) at each lamp, expose the street lamp cable and separate each share, so as to check the current with the clamp meter (the clamp meter needs to hit the highest level of the current file) Bit); starting from the first xenon lamp to detect the current according to the file, the sending and discharging operators at the control cabinet and the on-site detection current personnel should be equipped with walkie-talkies for timely contact. In the case of step-by-step detection, the clamp ammeter must be clamped to the cable before it can be ready to inform the power transmission personnel to instantaneously transmit power. The method does not need to manually cut off the main cable and the street lamp load, and does not bring new troubles to the street lamp cable. Through years of practice, we believe that the detection method is convenient and fast, and the testing instrument is a standing meter for us, without the need to purchase testing instruments.

Third, the use of street lamp cable fault tester detection

At present, there is a three-in-one instrument for collecting road cable path detection, buried depth measurement and fault point positioning. The detector is small in size and placed in a portable toolbox. It is light in weight and easy to operate by a single person. It is powered by a battery and does not require a 220V power supply. It is suitable for field operations. Cable path finding, buried depth, and fault location are simultaneously completed. High, free from external interference; not affected by cable underground conditions (bifurcation, joint distortion, winding), like mine detection, point-to-point to find fault points, the error is in centimeters; not affected by ground conditions, such as floor tiles, greening Belt, cement surface, etc. The detector is composed of a transmitter and a receiver, and the transmitter can adopt single-frequency transmission or radio frequency transmission according to the situation on the spot (the audio is suitable for long distance, the radio frequency is suitable for close range and interference); the receiver passes the induced magnetic The bar sensing signal determines the path and fault point of the street lamp cable, and is easy to operate, and accurately locates the fault point of the street lamp cable.