By hvhipot 
The DC hipot test Kit under HV Hipot Electric Co., Ltd. can help many power workers conduct various power tests more conveniently.
Key Test Procedures
1. DC Withstand (Hipot) Test
Purpose: Verify insulation strength.
Steps:
Disconnect all power series resonances.
Ramp up DC voltage in 10�C20% steps to target (e.g., 100 kV for 50-kV cable).
Hold voltage 5�C15 minutes (per standards like IEEE 95).
Monitor leakage current: Sudden spikes indicate failure.
Ramp down slowly; discharge with grounding rods.
2. Leakage Current/Polarization Index (PI)
Purpose: Detect moisture/contamination.
Method:
Apply 80% operating voltage.
Measure leakage current at 1 minute (I1) and 10 minutes (I10).
PI = I10I I1:
PI > 2.0 = Healthy insulation
PI < 1.0 = Severe degradation
3. Ramp Test (R&D/Failure Analysis)
Gradually increase voltage until breakdown.
Critical Safety
Grounding: Use dual-point grounding before/after tests.
Discharge: Short circuits with grounding sticks―capacitors retain lethal energy!
Clearance: Maintain >30 kV/m distance + barriers.
Remote Operation: Always control tests from a shielded location.
Challenges & Solutions
Ripple in DC: Use LC filters (keep ripple <3%).
Surface Leakage: Clean surfaces; apply guard electrodes.
Space Charge Buildup: Limit test duration (critical for XLPE cables).
Partial Discharges: Not detectable with pure DC; use VLF AC for PD tests.