(1) Find out the cause of the fault and the basic condition of the cable, such as whether there is a fault or a fault during the trial operation, a new cable or a long-running cable, the approximate length of the cable, whether there is a joint in the middle of the cable, whether the cable has been previously There has been a failure, whether the cable is directly buried or laid in the cable trough, the type of cable, etc.
(2) Both ends of the cable must be disconnected from other lines to ensure that the cable has no power. The environment around the cable is in a safe state.
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(3) Before connecting the cable, the tester must note that each phase of the cable is connected to the ground with a short-circuit wire, and one end of the short cable must be grounded, and the other end must be connected to the discharge of each phase of the cable. Other electrical appliances, such as capacitors, test transformers, etc., should be discharged before wiring. In a word, it is necessary to develop the operating habit. Before each operation, pay attention to the operation and circuit connection of the electrical appliance, put it out first, and then operate it.
(4) During the test, first use the low-voltage pulse function of the flashmeter to test the total length of each phase of the cable to see if the waveforms of the three-phase armor test are consistent; for most high-resistance faults, the test waveforms of each phase are consistent. For low-resistance faults and high-blocking phase faults, the test waveform of the fault phase is inconsistent with the total length of the cable under test, and the distance to the fault can be directly measured with low-voltage pulses.
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