Intelligent DC high voltage generator operation steps:
4.1 Preparation before use
4.1.1 The tester should be inspected for its integrity before use. The connecting cable should be free of open circuit and short circuit, and the equipment should be free from damage such as cracks.
4.1.2 Take the voltage doubler out of the chassis and place it in a suitable safe position. Connect the power cable, cable and ground wire respectively. The protective grounding wire and the working grounding wire and the grounding wire of the discharge bar are separately connected to the ground wire of the test piece (ie, one point is grounded). It is strictly forbidden to connect the grounding wires in series. For this purpose, a dedicated ground wire should be used. (See Figure 4).
Figure 4 Schematic diagram of the test loop grounding line
4.1.3 Place the power switch in the off position and check that the voltage regulator is in the zero position. Overvoltage and overcurrent protection are set at appropriate positions, typically 1.15 - 1.20 times the test voltage value.
4.2 No-load boost test and verification of overvoltage protection setting
4.2.1 Turn on the power switch, then the green light is on, indicating that the power is on.
4.2.2 Press the red button, the red light will be on, indicating that the high voltage is on.
4.2.3 Adjust the voltage regulator gently in the clockwise direction, and the output will start to boost from zero. After rising to the required voltage, record the ammeter reading for the specified time and check the control box and output cable for abnormalities and sounds. If necessary, calibrate the DC high voltage indication on the control box with an external high voltage divider.
4.2.4 Raise the voltage to the overvoltage protection setting value, the internal protection circuit should be activated, the green light is on and the red light is off.
4.2.5 Return the voltage regulator to zero and turn off the power switch.
4.3 Leakage and DC withstand voltage test on the test sample
4.3.1 After the 5.1 – 5.2 inspection test is carried out to confirm that there is no abnormality in the test, the leakage of the test sample and the DC withstand voltage test can be started. Connect the test sample, ground wire, etc., and turn on the power after checking.
4.3.2 Boost to the required voltage or current according to steps 5.2.1 – 5.2.3.
The boosting speed is preferably 3 - 5 kV per second. It is also necessary to monitor the current meter charging current not to exceed the maximum charging current of the tester when boosting the large capacitance sample.
For small capacitor samples such as zinc oxide surge arresters, magnetic blow arresters, etc., first rise to 95% of the required voltage (current), and then slowly rise to the required voltage (current). The voltage (current) value is then read from the digital display. To perform a 0.75 UDC-1 mA measurement on a zinc oxide surge arrester, first rise to the UDC-1mA voltage value and then press the yellow button. The voltage is then reduced to 75% and remains in this state for one minute. The microamps can be read at this time. After the measurement is completed, adjust the voltage counter to return to zero counterclockwise and press the green button. Press the red button when you need to boost again. Select automatic zinc oxide arrester and oil immersed transformer measurement function, you can directly test automatically.
4.3.3 After the test is completed, turn the voltage regulator counterclockwise back to zero, press the green button to turn off the power switch.
4.4 Several measurement methods
4.4.1 During general measurement, after connecting the line, first suspend the line connecting the sample, and after rising to the test voltage, read the corona and stray current I' during the empty test, and then connect the test sample to the test. The voltage reads the total current I1.
Sample leakage current: I0 = I1 – I'
4.4.2 When it is necessary to accurately measure the leakage current of the test article, the GL type high-voltage micro-ampere meter should be connected to the high-voltage side (see Figure 5a).
Figure 5 a Micro-ampere meter access sample Cχ high-voltage side wiring diagram Micro-ampere meter must have metal shielding, shielded wire should be used to connect with the sample. The shield lead of the high voltage lead should be tightly connected to the shield at the instrument end. If the effect of the surface leakage current of the sample is to be excluded, it can be connected to the shield of the high-voltage lead after a few turns of the bare metal cord at the high potential end of the sample (see Figure 5b).
b Excluding sample Cχ surface influence wiring diagram
4.4.3 For the case where the grounding ends of the test pieces such as zinc oxide and magnetic blower are separable, the method of measuring the current meter at the bottom (ground potential side) of the sample may be used. However, shielded wires must also be used (see Figure 6a). When the influence of the leakage current on the surface of the sample is to be excluded, a soft bare copper wire may be wound around the ground potential of the sample for several turns and connected to the shield of the shield wire (see Figure 6b).
4.4.4 After the test is completed, turn the voltage regulator counterclockwise back to zero, press the green button to turn off the power switch.
4.4.5 Small capacitors such as zinc oxide surge arresters are generally discharged through the internal pressure measuring resistor of the double pressure cylinder. For large capacitance samples such as cables, the voltage of the test sample is generally self-discharged to less than 20% of the test voltage, and then discharged through the matched discharge rod. After the test sample is fully discharged and the ground wire is hung, the removal of the high voltage lead and the replacement of the wiring work are allowed.
4.5 Operation after protection action During the use, the red light is off, the green light is on, and the DC high voltage is lowered, which is the relevant protection action. In this case, follow the steps below.
4.5.1 Turn off the power switch and the panel indicators are off.
4.5.2 Return the voltage regulator to the zero position.
4.5.3 After one minute, the low-voltage capacitor is fully discharged after standby, and then the power switch is allowed to be turned on again. After the no-load test is repeated and the situation is ascertained, the test can be boosted again.
4.1 Preparation before use
4.1.1 The tester should be inspected for its integrity before use. The connecting cable should be free of open circuit and short circuit, and the equipment should be free from damage such as cracks.
4.1.2 Take the voltage doubler out of the chassis and place it in a suitable safe position. Connect the power cable, cable and ground wire respectively. The protective grounding wire and the working grounding wire and the grounding wire of the discharge bar are separately connected to the ground wire of the test piece (ie, one point is grounded). It is strictly forbidden to connect the grounding wires in series. For this purpose, a dedicated ground wire should be used. (See Figure 4).
Figure 4 Schematic diagram of the test loop grounding line
4.1.3 Place the power switch in the off position and check that the voltage regulator is in the zero position. Overvoltage and overcurrent protection are set at appropriate positions, typically 1.15 - 1.20 times the test voltage value.
4.2 No-load boost test and verification of overvoltage protection setting
4.2.1 Turn on the power switch, then the green light is on, indicating that the power is on.
4.2.2 Press the red button, the red light will be on, indicating that the high voltage is on.
4.2.3 Adjust the voltage regulator gently in the clockwise direction, and the output will start to boost from zero. After rising to the required voltage, record the ammeter reading for the specified time and check the control box and output cable for abnormalities and sounds. If necessary, calibrate the DC high voltage indication on the control box with an external high voltage divider.
4.2.4 Raise the voltage to the overvoltage protection setting value, the internal protection circuit should be activated, the green light is on and the red light is off.
4.2.5 Return the voltage regulator to zero and turn off the power switch.
4.3 Leakage and DC withstand voltage test on the test sample
4.3.1 After the 5.1 – 5.2 inspection test is carried out to confirm that there is no abnormality in the test, the leakage of the test sample and the DC withstand voltage test can be started. Connect the test sample, ground wire, etc., and turn on the power after checking.
4.3.2 Boost to the required voltage or current according to steps 5.2.1 – 5.2.3.
The boosting speed is preferably 3 - 5 kV per second. It is also necessary to monitor the current meter charging current not to exceed the maximum charging current of the tester when boosting the large capacitance sample.
For small capacitor samples such as zinc oxide surge arresters, magnetic blow arresters, etc., first rise to 95% of the required voltage (current), and then slowly rise to the required voltage (current). The voltage (current) value is then read from the digital display. To perform a 0.75 UDC-1 mA measurement on a zinc oxide surge arrester, first rise to the UDC-1mA voltage value and then press the yellow button. The voltage is then reduced to 75% and remains in this state for one minute. The microamps can be read at this time. After the measurement is completed, adjust the voltage counter to return to zero counterclockwise and press the green button. Press the red button when you need to boost again. Select automatic zinc oxide arrester and oil immersed transformer measurement function, you can directly test automatically.
4.3.3 After the test is completed, turn the voltage regulator counterclockwise back to zero, press the green button to turn off the power switch.
4.4 Several measurement methods
4.4.1 During general measurement, after connecting the line, first suspend the line connecting the sample, and after rising to the test voltage, read the corona and stray current I' during the empty test, and then connect the test sample to the test. The voltage reads the total current I1.
Sample leakage current: I0 = I1 – I'
4.4.2 When it is necessary to accurately measure the leakage current of the test article, the GL type high-voltage micro-ampere meter should be connected to the high-voltage side (see Figure 5a).
Figure 5 a Micro-ampere meter access sample Cχ high-voltage side wiring diagram Micro-ampere meter must have metal shielding, shielded wire should be used to connect with the sample. The shield lead of the high voltage lead should be tightly connected to the shield at the instrument end. If the effect of the surface leakage current of the sample is to be excluded, it can be connected to the shield of the high-voltage lead after a few turns of the bare metal cord at the high potential end of the sample (see Figure 5b).
b Excluding sample Cχ surface influence wiring diagram
4.4.3 For the case where the grounding ends of the test pieces such as zinc oxide and magnetic blower are separable, the method of measuring the current meter at the bottom (ground potential side) of the sample may be used. However, shielded wires must also be used (see Figure 6a). When the influence of the leakage current on the surface of the sample is to be excluded, a soft bare copper wire may be wound around the ground potential of the sample for several turns and connected to the shield of the shield wire (see Figure 6b).
4.4.4 After the test is completed, turn the voltage regulator counterclockwise back to zero, press the green button to turn off the power switch.
4.4.5 Small capacitors such as zinc oxide surge arresters are generally discharged through the internal pressure measuring resistor of the double pressure cylinder. For large capacitance samples such as cables, the voltage of the test sample is generally self-discharged to less than 20% of the test voltage, and then discharged through the matched discharge rod. After the test sample is fully discharged and the ground wire is hung, the removal of the high voltage lead and the replacement of the wiring work are allowed.
4.5 Operation after protection action During the use, the red light is off, the green light is on, and the DC high voltage is lowered, which is the relevant protection action. In this case, follow the steps below.
4.5.1 Turn off the power switch and the panel indicators are off.
4.5.2 Return the voltage regulator to the zero position.
4.5.3 After one minute, the low-voltage capacitor is fully discharged after standby, and then the power switch is allowed to be turned on again. After the no-load test is repeated and the situation is ascertained, the test can be boosted again.
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