Industry news
Attention to use of cable fault tester
Source：Shandong Ketong Author：Shandong Ketong Date：2020-03-25 Visits：693
Precautions for use of cable fault tester
According to the manufacturer of the withstand voltage tester, according to the fault detection principle, when the instrument is in the flashover triggering mode, the flashover echo formed by the instantaneous breakdown discharge at the fault point is a random single transient waveform, so the tester shall have the function of storing the oscilloscope, which can capture and display the single transient waveform. The instrument adopts digital storage technology, uses high-speed A / D converter to sample, converts the input transient analog signal into digital signal in real time, stores it in high-speed memory, processes it by CPU microprocessor, sends it to LCD display control circuit, turns it into sequential dot matrix information, then displays the current sampling waveform parameters on LCD screen.
Common faults and precautions in use
1. When testing with pulse method, pay attention to shake off all equipment in the station and measure on the outermost line.
2. When the flashover method is used for testing, the trigger working mode switch must be placed in the "flashover" position.
3. Pay attention to personal safety and equipment safety when using direct flash method or impulse flash method for testing. The ground wire must be connected.
4. After the flashover test of the cable fault tester, cut off the power supply, remove the connecting wire between the instrument and the high-voltage test device, and discharge the stored charge of the high-voltage capacitor and cable. When discharging, the current limiting resistor R should be added first to limit the discharge current to make the current discharge slowly. After the voltage on the capacitor is reduced, the resistance in the discharge circuit directly to the ground is zero, and the instantaneous discharge current can reach several hundred amperes, which will cause serious equipment or personal accidents.
5. In the process of direct flash test, it is necessary to monitor the leakage current of the fault. If the current suddenly increases and the fault flashover does not occur, immediately reduce the test voltage and use the flash test instead.
According to the manufacturer of the withstand voltage tester, according to the fault detection principle, when the instrument is in the flashover triggering mode, the flashover echo formed by the instantaneous breakdown discharge at the fault point is a random single transient waveform, so the tester shall have the function of storing the oscilloscope, which can capture and display the single transient waveform. The instrument adopts digital storage technology, uses high-speed A / D converter to sample, converts the input transient analog signal into digital signal in real time, stores it in high-speed memory, processes it by CPU microprocessor, sends it to LCD display control circuit, turns it into sequential dot matrix information, then displays the current sampling waveform parameters on LCD screen.
Common faults and precautions in use
1. When testing with pulse method, pay attention to shake off all equipment in the station and measure on the outermost line.
2. When the flashover method is used for testing, the trigger working mode switch must be placed in the "flashover" position.
3. Pay attention to personal safety and equipment safety when using direct flash method or impulse flash method for testing. The ground wire must be connected.
4. After the flashover test of the cable fault tester, cut off the power supply, remove the connecting wire between the instrument and the high-voltage test device, and discharge the stored charge of the high-voltage capacitor and cable. When discharging, the current limiting resistor R should be added first to limit the discharge current to make the current discharge slowly. After the voltage on the capacitor is reduced, the resistance in the discharge circuit directly to the ground is zero, and the instantaneous discharge current can reach several hundred amperes, which will cause serious equipment or personal accidents.
5. In the process of direct flash test, it is necessary to monitor the leakage current of the fault. If the current suddenly increases and the fault flashover does not occur, immediately reduce the test voltage and use the flash test instead.
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