NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
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NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–CCTV Tester
Four methods to identify the fault of the cable identification instrument, how many do you know! 1. Sound measurement method The so-called sound measurement method is to search according to the sound of the faulty cable discharge. This method is more effective for the flashover discharge of the high-voltage cable core wire to the insulation layer. The equipment used in this method is the four major methods of judging the fault of the cable identification instrument, how many do you know! 1. Sound measurement method The so-called sound measurement method is to search according to the sound of the faulty cable discharge. This method is more effective for the flashover discharge of the high-voltage cable core wire to the insulation layer. The equipment used in this method is a DC withstand voltage tester.
Be sure to pay attention to safety when using this method, and special personnel should be set up to monitor the end of the test equipment and the end of the cable. 2. The bridge method is to measure the DC resistance value of the cable core wire by the double-arm bridge, and then accurately measure the actual length of the cable, and calculate the fault point according to the proportional relationship between the cable length and the resistance. This method is suitable for direct short-circuit between cable cores or short-circuit point contact resistance less than 1ΩThe fault of the fault, the judgment error is generally not more than 3m, and the contact resistance of the fault point is more than 1ΩIf the fault occurs, the resistance can be reduced to 1 by adding a high voltage to burn through.ΩHereinafter, measure again according to this method.
3. Capacitance current measurement method During the operation of the cable, there is capacitance between the core wires and between the core wires to the ground. The capacitance is evenly distributed, and the capacitance is linearly proportional to the length of the cable. The capacitance current measurement method is based on this principle. The measurement is very accurate for the measurement of the cable core wire disconnection fault. 4. The zero-potential method is also the potential comparison method. It is suitable for the ground fault of the cable core with short length. Using this method is simple and accurate to measure, and does not require precise instruments and complex calculations.
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