The DC hipot tester under Wuhan UHV can help many power workers conduct various power tests more conveniently.

Test Procedure

1.Preparation

De-energize the equipment and disconnect all wiring.

Discharge any residual energy using grounding sticks.

Clean surfaces to prevent surface leakage.

2.Setup

Connect the hi-pot tester:

HV lead → Device terminal.

Ground lead → Equipment ground.

Place barriers (>30 kV/m clearance).

3.Voltage Ramp-Up

Start at 0 kV.

Increase voltage in 10% steps (e.g., 10 kV → 20 kV → ...).

Hold each step for 1 minute to monitor stability.

4.Hold at Test Voltage

Reach target voltage (e.g., 2× operating voltage).

Maintain for 5–15 minutes (per IEEE 95/IEC standards).

Monitor leakage current continuously:

Pass: Steady/low current (< manufacturer limit).

Fail: Sudden spike or > threshold.

5.Ramp-Down & Discharge

Reduce voltage slowly to 0 kV.

Discharge using grounding sticks for ≥1 minute.

Verify zero voltage with a voltmeter.

Critical Safety Rules

Remote Operation: Control tester from a shielded area.

Dual Grounding: Ground equipment before and after connections.

No Touch Zone: Never contact equipment during testing.

Discharge Capacitors: HIGH RISK! DC systems store lethal energy.

Key Interpretation

Pass: Leakage current stable and within specs.

Fail: Current jumps >20% or fluctuates wildly.

Caution for XLPE Cables: Avoid DC hipot (use VLF AC instead) – DC can cause insulation damage!

Warning: Only qualified personnel should perform tests. Follow equipment-specific standards (e.g., IEEE 95 for cables). Always prioritize manufacturer guidelines.