Irreplaceable Advantages of VLF Testing

1.Enhanced Safety & Insulation Protection: Uses very low frequency AC (0.1 Hz) to reverse polarity, preventing harmful space charge buildup inherent in DC testing (critical for XLPE). Applies controlled overvoltage (2-3x rated voltage) to reveal weaknesses without damaging sound insulation.

2.Accurate Early Fault Detection: Highly sensitive to slow-forming defects (water trees, voids, aging interfaces), matching power-frequency AC effectiveness. Integrates tanδ measurement to quantify aging trends (e.g., >0.1% signals risk) and simultaneous PD/leakage current monitoring for defect localization.

3.Superior Field Practicality: Compact, portable equipment uses minimal power (~1/500th of AC testing), enabling use in tight spaces. Delivers fast results—diagnostic and withstand tests completed in 15-60 minutes per circuit, significantly faster than power-frequency AC.