This practical guide shows you how to complete a signed, QR-verified MV Switchgear, VCB/SF6 Breaker & MV Cable VLF Test Report certificate in OhmCert Module #30 and how to troubleshoot non-compliant readings on site.

1. Step-by-Step OhmCert UI Workflow

  1. Open Module #30: Navigate to MV Switchgear, VCB/SF6 Breaker & MV Cable VLF Test Report from the Dashboard.
  2. Load a 1-Click Standard Annex Preset: Open the blue Standard Annex banner at the top and click a preset (such as "34.5 / 36 kV Primary Substation Vacuum Circuit Breaker (VCB) + XLPE Feeder") to populate target limits automatically.
  3. Enter Your Field Measurements: Fill in the measured inputs (Rated Medium Voltage System Level Ur, Circuit Breaker Interruption Medium, OEM Max Main Contact Resistance Limit, Measured Contact Resistance Pole L1 (at >= 100 A DC), Measured Contact Resistance Pole L2 (at >= 100 A DC), Measured Contact Resistance Pole L3 (at >= 100 A DC), Measured Breaker Opening Time Pole L1, Measured Breaker Opening Time Pole L2, Measured Breaker Opening Time Pole L3, Worst-Case Breaker Closing Time (Max Pole), Main Pole Insulation Resistance (at 5 kV DC), MV XLPE Cable 0.1 Hz VLF Tan-Delta at Uo (10^-3, optional)). Blank inputs stay neutral PENDING.
  4. Complete the 12-Point Checklist: Grade each item, attach photos if needed, and export the SHA-256 signed PDF certificate.

2. Worked Numerical Field Case Study

Scenario: 34.5 / 36 kV Primary Substation Vacuum Circuit Breaker (VCB) + XLPE Feeder (IEC 62271-100 36 kV) — Healthy 1250 A withdrawable VCB cubicle and 34.5 kV XLPE feeder VLF tan-delta check..

  • Rated Medium Voltage System Level Ur: 36.0 kV
  • Circuit Breaker Interruption Medium: Vacuum Circuit Breaker (VCB)
  • OEM Max Main Contact Resistance Limit: 60 uOhm
  • Measured Contact Resistance Pole L1 (at >= 100 A DC): 34 uOhm
  • Measured Contact Resistance Pole L2 (at >= 100 A DC): 36 uOhm
  • Measured Contact Resistance Pole L3 (at >= 100 A DC): 35 uOhm
  • Measured Breaker Opening Time Pole L1: 38.2 ms
  • Measured Breaker Opening Time Pole L2: 38.8 ms
  • Measured Breaker Opening Time Pole L3: 38.5 ms
  • Worst-Case Breaker Closing Time (Max Pole): 54.0 ms
  • Main Pole Insulation Resistance (at 5 kV DC): 12500 MOhm
  • MV XLPE Cable 0.1 Hz VLF Tan-Delta at Uo (10^-3, optional): 1.2 E-3

3. Engineering Troubleshooting: Corrective Actions When a Reading Fails

  1. Inspect, clean, or replace withdrawable tulip finger contacts or vacuum interrupters if contact resistance exceeds OEM uOhm limits or 50% inter-pole deviation.
  2. Lubricate hardened operating mechanism latches or replace sluggish trip coils when opening time or > 2.0 ms pole discrepancy fails.
  3. Localize damp cable joints or degraded terminations via VLF partial-discharge mapping if 0.1 Hz tan-delta exceeds 4.0 x 10^-3.

→ Try This Worked Example Live in Module #30 (MV Switchgear & VCB/VLF)