Precautions for operating the partial discharge tester:
1. Before applying voltage in the test, the test personnel must thoroughly and comprehensively inspect the circuit to avoid incorrect connections. Check whether the grounding wire at the test instrument is firmly connected to the grounding body. If the connection is not secure or the wire is accidentally kicked off during preparation, it may cause personal injury and equipment accidents.
2. For connecting wires, avoid exposing sharp tips to prevent corona discharge from the tips. Especially for partial discharge tests with higher voltage levels, it is necessary to thicken the high-voltage connecting wires and add anti-corona shields to reduce corona discharge caused by excessive field strength. The shielding cover must not come into contact with the porcelain skirt of the test object.
3. Generally, during the test, the partial discharge level of the test object is much higher than normal during voltage withstand and pre-boost stages. At this time, the instrument's meter will inevitably exceed the full scale. To prevent instrument damage, turn the coarse gain adjustment knob counterclockwise by one or more gears to keep the reading within the full scale. When the voltage drops to the measurement voltage, turn the coarse gain switch clockwise by one or more gears to record the measured value.
4. After calibrating with the charge calibrator, it must be disconnected from the high-voltage end and the power switch turned off. The fine gain adjustment knob of the instrument should not be adjusted further. Since the relationship between adjacent gears of the coarse gain switch is tenfold and the gear position is indicated, after boosting, an appropriate range can be selected based on the discharge level. When turning counterclockwise, each gear reduction expands the range tenfold; conversely, when turning clockwise, the range shrinks tenfold.
5. After completing the partial discharge test, the entire test system should be rechecked and recalibrated to verify that it matches the scale factor calibrated before the test, to avoid incorrect test results due to malfunctions in the test instrument or other components during the test.
