Test equipment: AC hipot test system
1. Power frequency AC hipot test system, test frequency 50Hz/60Hz
2. Variable frequency series resonant test system, test frequency 30~300Hz.
Preparation before the test
The cable should be placed at a normal temperature (20 ± 5℃) for at least 24 hours to eliminate the temperature stress caused during transportation or storage. Measure the insulation resistance using an ohmmeter (2500V) to ensure that the value is ≥ 100 MΩ (reference value), and eliminate obvious defects.
Connection and voltage rising
The non-test phase and the metal shielding layer should be reliably grounded to avoid the danger of induced voltage.
The voltage should be slowly increased from zero to the specified value at a rate of no more than 1 kV per second. After reaching the specified value, it should be maintained for 15 minutes. During this period, the leakage current changes need to be monitored.
Test result
During the test, there was no breakdown or flashover, and the leakage current remained stable (with no obvious upward trend), indicating that it was qualified. If any abnormalities occur, the voltage should be reduced, and the wiring or the defect of the cable itself should be checked. It is strictly prohibited to conduct repeated tests with the fault.