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Sonel Test Equipment

S-57 VLF High Voltage Insulation Tester

S-57 VLF High Voltage Insulation Tester

Regular price $44,811.95
Regular price Sale price $44,811.95
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Test the condition of the cables with VLF or DC slow voltage.  

The compact, robust and portable cable test set is used for testing of medium voltage cables in accordance to the standards IEEE400, IEC 60502-2, CENELEC HD 620 & 621 and DIN VDE 0276/620 & 621. The test is carried out with a low strain practice with VLF (very low frequency) test voltage at 0.1 Hz frequency.

VLF test enables detection of damages of the insulation within shortest test time. The S  VLF series device can test cables with extruded insulation (XLPE-, PE-, EPR-insulation) as well as cables with paper-oil insulation (PILC). Cable sheath testing with direct voltage is also possible.

Sonel offers online training course on the use of this product (instructional video and consultation with a specialist).



  • Extremely compact high-power VLF test device
  • Easily portable for 1-2 people
  • Simple operation: menu-assisted control with industrial class OLED display
  • Fully automatic test sequence
  • Integrated timer 1-300 min with automatic tripping
  • Integrated breakdown detection
  • Integrated fault time detection
  • Voltage measurement direct at HV output
  • Protective ground connection
  • High voltage start key interlock
  • Protective circuit / indication in accord. with EN 50191
  • Leakage current measurement during VLF test


Optional features

  • Data logging (USB stick) for VLF test sets
  • Frequency extension: 0.05 + 0.02 Hz
  • Customized test cables
  • Transport case
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