When doing capacitive load test, be sure to connect upper current resistance.
1. The tester should be checked for its integrity before use. The connecting cable should not be open and short circuit, and the equipment should not be damaged by breakage.
2. Place the chassis and pressure multiplier cylinder at appropriate positions and connect the power cable, cable and grounding wire respectively. The protection grounding wire, working grounding wire and grounding wire of discharge rod should be separately connected to the ground wire of the test product (i.e. one point grounding). Do not connect grounding wires in series. To do this, use a dedicated DHV ground cable.
3. Put the power switch in the off position and check the voltage regulator should be in the zero position. The overvoltage protection setting value is generally 1.1 times of the test voltage.
4. No-load boost verifies whether the overvoltage protection setting is sensitive.
5. Switch on the power switch. If the red light is on, the power is on.
6. Press the green button, and the green light is on, indicating that the hV is connected.
7. Gently adjust the voltage regulator clockwise, the output end of the voltage boost from zero, up to the required voltage, according to the specified time to record the ammeter reading, and check the control box and high voltage output line for abnormal phenomenon and sound.
Step down, return the potentiometer to zero, then press the red button to cut off the high voltage and turn off the power switch.
9. Conduct leakage and DC voltage test on the samples. After checking the test to confirm that there is no abnormal condition of the tester, the leakage and DC voltage test of the test products can be started. Connect the sample, ground wire, etc., and turn on the power after checking without error.
10. Boost voltage to desired voltage or current. The speed of boost is suitable for 3-5kV test voltage per second. For large capacitance sample voltage boost, also need to monitor the ammeter charging current does not exceed the charging current of the tester. For small capacitance test products such as zinc oxide arrester, magnetic blowing arrester, etc., first rise to 95% of the required voltage (current), and then slowly and carefully rise to the required voltage (current). Then read the voltage (current) value from the digital display meter. For 0.75UDC -- 1mA measurement of zinc oxide arrester, first rise to UDC1mA voltage value, and then press the yellow button, the voltage will be reduced to the original 75%, and keep this state. The current can be read at this point. After the measurement, the potentiometer counterclockwise back to zero, press the green button. Press the red button when you need to boost again.
If necessary, compare the voltage on the control box with an external high voltage divider.
11. After the test, reduce the voltage and turn off the power.
12. Several measurement methods
1) In general measurement, when the line is connected, the line connecting the sample is suspended first, and then read the corona and stray current I during the air test after rising to the test voltage, and then connect the sample to the test voltage to read the total current ⅰ 1; Io = ⅰ 1 -- I '
2) When it is necessary to measure the leakage current of the tested product, a high voltage microammeter shall be connected in series at the high voltage side (see the figure below).
Microammeter must have metal shielding, shielding wire should be used to connect with the test. The shielding lead of the high voltage lead shall be closely connected with the shielding of the instrument end. If the surface of the sample is dirty, the influence of the leakage current on the surface of the sample can be excluded. The high potential end of the sample can be connected with the shielding of the high voltage lead after several laps of the bare metal cord (see the following figure).
3) In the case that the grounding end of zinc oxide and magnetic blowing arrester can be disassembled, the ammeter can also be connected to the bottom of the test (ground potential side) for measurement. To eliminate the influence of the leakage current on the surface of the sample, the soft bare copper wire can be wound several times at the ground potential end of the sample and connected with the shielding of the shielding wire (see figure below).
13. For zinc oxide arrester and other small capacitance test products, the discharge time is usually very fast through the voltage measuring resistor. For large capacitance test products such as cables, it is generally required to wait until the test product voltage self-discharge to below 20% of the test voltage, and then discharge through the supporting discharge rod. The removal and replacement of high voltage leads can be carried out only after the grounding wire is hung up after the test product is fully discharged.
14. Operation after protection action
In the process of use, it is found that the green light is off, the red light is on, and the voltage drops, which is the relevant protection action. The power switch should be turned off. The indicators on the panel are off. Return the voltage regulator to zero and turn on the power switch after one minute when the low-voltage capacitor in the standby is fully discharged. Carry out the no-load test again and find out the situation after the booster test again.
Wuhan Xinshengneng Technology Co., LTD
