Cable fault tester field test method

The basic steps of the cable fault tester :

1) Find out the cause of the fault and the basic condition of the cable, such as whether the fault is caused by the operation or the pre-test. Is it a new cable or a long running cable? The approximate length of the cable? Is there any connector in the middle of the cable? There have been failures, whether the cable is buried directly or in cable trenches, cable types, etc.

2) It must be clear that both ends of the cable must be disconnected from other lines to ensure that the cable is not charged and the environment surrounding the cable is in a safe state.

3) The tester must pay attention to, each time before connecting with the cable, connect the phase wire of the cable to the ground with a short-circuiting wire. When the power is switched on, one end of the short-circuit wire must be grounded first, and the other end should be connected to each phase of the cable. *Electricity. For other electrical appliances, such as capacitors, test transformers, etc., before wiring and removing the connection cable, it is also necessary to pay attention to the first power and then the wiring. In short, to form operating habits, not afraid of trouble, before each operation, first pay attention to whether the operation of electrical appliances and the circuit connection, first put * electric operation.

4) When testing, first use the low-voltage pulse function of the flash tester to perform full-length test on each phase of the cable to see if the test waveforms are the same when using the three-phase armored test. For most high-impedance faults, the test waveforms for each phase are the same. For low-impedance faults and high-impedance faults with open-phase faults, the fault phase test waveform does not match the full length of the test cable, so that the fault distance can be directly measured with low-voltage pulses.

5) When using the high-voltage flashover test, whether the cable fault is a high-impedance fault or a low-impedance fault, the high-voltage flashover method can be used for testing. For low-resistance or disconnection faults that can directly measure the fault distance with low-voltage pulses, high-voltage flashovers are usually used for verification tests and precise determination of fault points.

During the high-voltage flashover test, it should be noted that no matter whether the cable is single-phase fault or multi-phase fault, when testing one fault phase, other cable phase lines should be short-circuited with the cable armor to reduce the interference of other cables and improve Test accuracy.

6) After the high-voltage flashover test is completed and the fault distance is determined, fault fine point determination can be performed. When the sound-magnetic synchronous fixed point instrument is used, fault fixed point and path detection work can be performed synchronously.