Par rapport aux essais de tenue en tension continue et aux essais de tenue en tension alternative à fréquence industrielle, les essais à très basse fréquence (VLF) offrent des avantages uniques :
1. Comparé au test de tenue en courant continu :
Better simulates operating conditions: Power equipment operates under AC voltage, and the electric field distribution under DC voltage differs from that under AC voltage. For solid-insulation equipment like XLPE cables, DC testing can create space charges within the insulation, potentially damaging it or masking underlying insulation defects. The electric field distribution under VLF AC voltage is consistent with the power frequency and does not cause space charge accumulation, making it a more effective and safer test method.Meilleure détection des défauts concentrés : les défauts tels que les décharges partielles sont plus facilement détectés sous tension alternative.
2. Comparé aux essais de tenue en courant alternatif à fréquence industrielle :
Portable equipment: As mentioned, the test current is drastically reduced, making the test equipment dozens of times lighter and smaller than power-frequency test sets, making it highly suitable for field use.Low power supply requirements: Requires very little capacity from the field power series resonance.Générateurs haute tension VLF