For non-destructive insulation withstand voltage tests on PE/XLPE plastic power cables, first confirm the cable voltage class, capacitance per kilometer, and test length during selection. Taking 10kV cables as an example, the capacitance of 16–240mm² cross-sections is approximately 0.15–0.38μF/km, and that of 35kV cables is approximately 0.11–0.19μF/km. The device output frequency is usually set to 0.1Hz. If the capacitance of a single cable section exceeds the rated load of the device, the voltage boosting process will trigger overcurrent protection, so sectional testing or a larger-capacity model is required.
The KDX-45 has a rated output of 45kV and is suitable for acceptance and preventive tests on 10kV and 35kV cables. It adopts cosine square wave output, and the flat-top section of the output voltage waveform is stable, making peak values easy to read. During on-site wiring, keep the high-voltage lead as short and straight as possible, ground the shielding layer at one end, and avoid routing parallel to adjacent energized busbars. Before testing, measure the insulation resistance with a megohmmeter and confirm there is no abnormality before boosting voltage; during voltage boosting, pause in stages and record the leakage current at each stage.
The device has overvoltage, overcurrent, and grounding protection functions. Operators should stand on insulating mats and set the test voltage and time limit according to regulations. After the test, cut off the power first, then fully discharge the cable with a discharge rod, and only remove the wiring after confirming there is no residual charge. Store the equipment in a dry and ventilated place, and regularly check the connection status of the high-voltage output cable and grounding wire.
It is suitable for on-site withstand voltage tests of 10kV and 35kV cross-linked polyethylene cables in power departments and industrial and mining enterprises, and can also be used for insulation withstand voltage inspection of generators, motors, and other equipment. For longer cables, it is recommended to calculate a sectional test plan based on capacitance to avoid long-term full-load operation of the device.
