How to quickly locate leakage points using high and low voltage clamp-on ammeters
The new method for quickly locating leakage faults is the four wire single flame clamp meter method. The search steps are as follows: First, disconnect the main circuit breaker in the substation area, connect the low-voltage four line output (including the zero line) in parallel, then connect a phase power supply, and use a high and low voltage clamp ammeter to measure and determine the leakage fault point phase by phase. The four wire single flame clamp meter method has a small workload, fast fault point identification, and low safety risks.
1. First end measurement judgment. Firstly, power off the leakage circuit in the distribution room (box). After verifying that there is no voltage, remove the three-phase fuses of circuit A, B, and C and disconnect the neutral wire (N) (if there is no fuse, disconnect the circuit output, including the neutral wire, and mark the phase sequence of the neutral wire and other phase wires). Connect four wires in parallel, take any one of the live wires and power on them, so that all four wires are powered on by a single fire. At this time, high and low voltage clamp ammeters can be used to measure the four wires separately. If the Gan line shows a high current value while the other three lines have very low or zero values, it indicates that a serious leakage fault has occurred with a high current value. If there are significant readings in all four line measurements, it indicates that each phase has varying degrees of leakage. Regardless of the situation, gradually search for the leakage fault point based on the principle of increasing current value first and then decreasing it.
2. Confirm the first shot again. After confirming the leakage fault phase at the front end of the distribution room (box), use an insulated rod clamp ammeter on the safety base outgoing pole to confirm the severe leakage fault phase with a high value again, and firmly remember the fault phase. Follow the faulty phase and gradually measure and search towards the receiving side.
3. Search for T-branch. When encountering the T-branch line measurement and search, use the T-branch pole as the reference, first measure the main line A1 point (in the direction of the receiving side), and then measure the branch line A2 point. If the leakage value at the measurement point A1 is high, while there is no leakage display at point A2. It indicates that the leakage fault point is still in the rear section of the main line, rather than on the T-branch line.
4. Search for cross branches. When encountering cross branch line measurement and search, take the cross branch pole as the reference and first measure the main line A1 point (in the direction of the receiving side). If there is no leakage display, it indicates that the fault point is at point A2 (on the "ten" side of the branch line) or point A3 (on the "one" side of the branch line). If there is leakage current at points A2 and A3 simultaneously, it indicates the presence of multiple grounding faults. The leakage fault point should be gradually identified based on the principle of increasing current value first and then decreasing current value. By following this and gradually, serious leakage faults or users can be quickly identified. This method is also very fast and accurate for detecting electricity theft on the front line and in one location.
