Use a clamp ammeter to check for low-voltage leaks and power theft
1, to determine whether the residual current action protector itself has a problem
The method is: in the distribution transformer, the control of low-voltage line AC contactor out of the phase line on the side of the fuse is disconnected, if the residual current action protector can be put into operation normally, it proves that the residual current action protector is good. Otherwise, the residual current action protector should be overhauled and replaced.
2, check to determine which phase of the phase line leakage
The method is: in the distribution transformer, the control of low-voltage line AC contactor outlet side of the neutral line disconnected, and then has been removed from the fuse core installed in one of the phase, with a clamp-on ammeter to measure the phase, the measured current is the leakage current of the phase. According to the same method in turn measured the leakage current of the remaining leakage phase.
In order to prevent the existence of phase grounding on the line (such as a line of people using a ground method of electricity theft, etc.) occurring large current damage to the instrument, the detection of the first clamp-on ammeter block on the large current block; if the detection value is very small, and then the clamp-on ammeter block converted to milliampere block detection.
3, after determining the existence of leakage phase line, determine the location of the leakage
Method is: in the distribution transformer, the phase line to be checked inserted fuse core, neutral line and the remaining two phases of the fuse are disconnected, boarding pole with a clamp-on ammeter to detect charged phase line to determine the location of the leakage. In order to improve efficiency, the boarding position can be selected in the middle of the line, through the detection of leakage parts in the first half of the line or the second half, and then to the suspected leakage of the line section detection. And so on, to narrow the detection range. * Afterwards, the insulator of the pillar of that phase line within the smaller range determined is tested, and the phase line of the user connection line connected to that phase line within the range is tested (either on the ground or at the same time when the insulator is tested), in order to determine the specific part of the leakage.
In the case of low-voltage line power supply, can also be identified within the scope of suspicion of low-voltage users connected to the household line with a clamp-on ammeter for detection. Detection, single-phase users of the phase line and the neutral line should be placed in the jaws of the clamp-on ammeter at the same time, three-phase power users of the three phase line and the neutral line should also be put into the jaws at the same time. If there is no leakage fault, the load current flux of the phase and zero, clamp ammeter indication is also zero; such as leakage current, clamp ammeter can detect leakage current to.
4, check the user's internal lines and equipment with or without leakage
Method is: the user's power supply into the house line with a clamp-on ammeter to measure leakage current, while the user's power equipment, lamps and lanterns one by one into the exit, by looking at the clamp-on ammeter to detect changes in leakage current to find leakage equipment and lamps and lanterns. If all the equipment lamps and lanterns are good, or there is a leakage of equipment have been withdrawn, but the clamp-on ammeter shows that the user still exists leakage current, it may be the user's low-voltage line leakage, should be dealt with on a case-by-case basis. For pre-buried concealed pipeline leakage fault, can only be taken to change the line or rewiring of the treatment method.
