qiao@hvtest.cc15871365102
  • What is the difference between IR test and VLF test?

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


    192



    1. Fundamental Principles

    IR Testing: Applies low-voltage DC (typically 500V–10kV) to measure leakage current and calculate insulation resistance (in MΩ or GΩ). It is a static resistance measurement, analogous to using a multimeter.

    VLF Testing: Applies 0.1 Hz very low-frequency AC high voltage (2–3 times rated cable voltage, e.g., 28kV for a 10kV cable) to simulate power-frequency voltage stress, performing a dynamic withstand test + diagnostics.


    2. Core Objectives
    IR Testing:
    Detects bulk insulation degradation (e.g., moisture ingress, contamination, major damage).
    Provides the Polarization Index (PI) to assess moisture absorption trends.
    VLF Testing:
    Identifies latent defects (water trees, voids, interfacial aging).
    Verifies cable withstand strength (whether breakdown occurs under high voltage).

    Combines tan delta (tanδ) and partial discharge (PD) measurements to locate defects.


    3.Safety & Applicability
    IR Testing:
    Inherently safe (low DC voltage doesn’t damage insulation).
    Unsuitable for XLPE cable diagnostics (cannot detect water trees).
    VLF Testing:
    Only safe high-voltage method (0.1 Hz polarity reversal prevents space charge buildup in XLPE).
    Mandated by international standards (IEEE 400.2 / GB/T 12706.4 for XLPE cables).


    Das könnte Ihnen auch gefallen

    • Haben Sie Fragen!

      Zögern Sie nicht, uns jederzeit zu kontaktieren
      Kontaktiere uns
    • Besuchen Sie uns

      Gebäude 6, Optics Valley Optical-Mechanical Industrial Park, 84 Gaoxin 5 Road,
      East Lake New Technology Development Zone, Stadt Wuhan, Provinz Hubei, China

    • Schreiben Sie uns eine E-Mail

      qiao@hvtest.cc

    • Rufen Sie uns an

      +86-15871365102