The Method of Clamp Ammeter Checking Low Voltage Line Leakage
For the method of clamp Ammeter to check the leakage of low-voltage lines, how to use clamp Ammeter to check the leakage and stealing of low-voltage lines, and whether there is a problem with the residual electricity or the maintenance device itself.
The Method of Clamp Ammeter Checking Low Voltage Line Leakage
The clamp Ammeter is used for single-phase power supply to clamp the neutral line and live line at the same time. If there is indication, there is leakage. Three phase neutral free power supply uses clamp Ammeter to clamp three live wires at the same time. If there is indication, there is leakage. Three phase four wire power supply uses clamp Ammeter to clamp four wires at the same time, and there is leakage when there is indication.
How to use clamp Ammeter to check the leakage and theft of low-voltage lines?
Clamp Ammeter is composed of current transformer and Ammeter. The iron core of the current transformer can be opened when the wrench is tightened; The wire through which the measured current passes can pass through the open gap of the iron core without cutting it, and when the wrench is unfolded, the iron core closes.
The tested circuit wire passing through the iron core becomes the primary coil of the current transformer, and the current passing through it induces a current in the secondary coil. Then the Ammeter connecting the secondary coils will have an indication - measuring the current of the line under test.
Clamp type Ammeter can change different range by shifting the change-over switch. But it is not allowed to operate with power when shifting gears. The precision of clamp shaped watches is not high in general, ranging from 2.5 to 5 levels.
For convenience of use, there are also conversion switches with different ranges in the meter for measuring different grades of current and voltage.
When measuring the current with a popular Ammeter, it is necessary to cut off the circuit and shut down the machine before connecting the Ammeter for measurement. This is very troublesome, and sometimes the normal operation of the electric idea does not allow this.
At this point, it is much more convenient to use the clamp Ammeter, which can measure the current without cutting the circuit. Clamp on Ammeter is the best thing to reflect on the leakage of low-voltage lines or check the theft of electricity.
1. Identify whether there is a problem with the residual electrical activity maintenance device itself
Method: At the distribution transformer, disconnect the fuse on the phase line of the AC contactor on the output side of the low-voltage line. If the residual power action maintenance device can be put into operation normally at this time, it is confirmed that the residual power action maintenance device is good. Otherwise, it is necessary to check and modify the maintenance device for replacing residual electrical activities.
2. Reflect on which phase line is causing leakage
Method: At the distribution transformer, disconnect the neutral line at the outgoing line side of the AC contactor that controls the low-voltage line, install the removed fuse core on one of the phases, and measure the phase with a clamp Ammeter. The measured current is the leakage current of the phase. Measure the leakage current of other leakage phases in sequence using the same method.
3. After determining the phase line with leakage, determine the status of leakage
Method: At the distribution transformer, insert the phase line to be introspected into the fuse core, disconnect the neutral line and the fuses of other two phases, and use clamp Ammeter to detect the live phase line to determine the leakage status. To improve efficiency, the pole climbing position can be selected in the middle of the line. After testing, it is determined whether the leakage position is in the first half or the second half of the line, and then it is detected in the suspected leakage section of the line. By analogy, reduce detection limitations.
Finally, the phase line post insulators within the determined small limits will be tested and
