The KDX-90 ultra-low frequency withstand voltage test device outputs 0–90 kV peak voltage at a frequency of 0.1 Hz, with a load capacity sufficient for 1.1 μF cable specimens and a voltmeter accuracy of class 1.5. The device has built-in overcurrent and overvoltage protection, and a voltage waveform distortion of ≤3% full scale + 0.5 kV, making it suitable for AC withstand voltage tests on 6 kV–35 kV cross-linked polyethylene cables.
The 0.1 Hz ultra-low frequency output can equivalently simulate a 50 Hz power-frequency electric field, making the insulation assessment of XLPE cables closer to actual operating conditions. The 90 kV peak voltage covers the test requirements of 35 kV class cables, and the 1.1 μF load capacity can accommodate longer cable sections, allowing the entire section to be tested with a single connection and reducing the workload of sectional disconnection and reconnection. The class 1.5 meter accuracy meets on-site reading requirements, and the waveform distortion is controlled at ≤3% full scale + 0.5 kV, ensuring the quality of the test voltage waveform.
The device is equipped with dual overcurrent and overvoltage protection, monitoring the output circuit status in real time during voltage rise, and automatically cutting off the output and issuing an alert in case of abnormality. Compared with DC withstand voltage tests, ultra-low frequency AC voltage avoids damage to XLPE insulation caused by space charge accumulation and reduces the risk of insulation degradation after testing, making it suitable for handover acceptance and preventive testing scenarios.
Before use, confirm that the specimen capacitance does not exceed 1.1 μF, connect in the order of high-voltage output terminal—specimen—ground terminal, and only raise the voltage after reliable grounding. Set the test voltage according to regulations, raise the voltage at a uniform and controllable rate, and after reading the 1 min withstand voltage data, automatically lower it back to zero. The device is suitable for cable withstand voltage verification work in substations, cable manholes, and laboratory environments, and it is recommended that it be operated by personnel with high-voltage testing qualifications.
