(1) Insulation resistance test
Insulation resistance is the most basic insulation index of electrical equipment and circuits. The resistance corresponding to the leakage current flowing through the dielectric is called the insulation resistance after a certain period of time after the polarization process is completed.
When a DC High Voltage Generator is used to boosting the
material under test, the current on the material under test does not reach a stable value instantaneously, but rather has an attenuation process. At the same time of boosting, a relatively large charging current flows through, followed by a relatively long and slowly decreasing absorption current, and finally a relatively stable conductive current. The higher the measured resistance value, the longer it takes to reach equilibrium. Therefore, in order to correctly read the measured resistance value during the measurement, it should be read after the value has stabilized.
(2) DC withstand voltage and leakage test
For good insulation, the leakage current is very small under the action of DC voltage. At the same time, at the same DC voltage, the current through the insulation decreases with the increase of the boosting time. In the case of good insulation, as the applied DC voltage increases, the leakage current increases due to the faster ion movement speed. However, in the not too high voltage range, the leakage current is linear with the increase of the applied voltage, and the increase is small.
(3) Cable DC withstand voltage test
The voltage after the test is 3 times the rated voltage of the cable. Under the specified test voltage (the test voltage is increased in 0.5 times the rated voltage of each stage, and each segment stays for 1 min, recording the leakage current; Note: If the leakage current increases disproportionately with the voltage, it must be analyzed and checked in time. Before the withstanding voltage test, check the withstand voltage of the DC High Voltage Generator with a high voltage megohmmeter.
(4) Zinc oxide lightning arrester test
DC High Voltage Generator, specially equipped with zinc oxide lightning arrester test function, can raise the voltage to the leakage current of 1mA, and then press the 0.75 times button, the instrument can automatically reduce the voltage to 0.75 times the voltage, the leakage current at this time is 0.75 times the zinc oxide that needs to be measured U1mA leakage current. This current can reflect the insulation state of the zinc oxide lightning arrester.
