latest company case about Xi'an Xu&Hui Electromechanical Technology Co., Ltd. Certifications

Site Conditions

• Cable ends fully disconnected — one end at the wind farm step-up substation, the other at the turbine base transformer.
• Cable route clearly marked with indicator posts; however, joint marker positions were inaccurate.
• Terrain: rolling grassland with volcanic soil, moderate South Sulawesi highland winds.
• Insulation Resistance (Pre-Test): Phase A: 400 MΩ, Phase B: 368 MΩ, Phase C: 415 MΩ — indicating a high-resistance fault.

Test Equipment Deployed

Testing Procedure

Step 1: Insulation Verification

Pre-test measurements confirmed all phases maintained 368–415 MΩ to earth, ruling out a solid ground fault and indicating a single-phase high-resistance fault condition.

Step 2: Coarse Fault Location

The XHGG502 Host Locator was connected at the substation end. Using the Low-Voltage Pulse method on Phase B to earth, the reflected waveform indicated a total cable length of 14.8 km. Phases A and C also returned 14.8 km full-length waveforms, confirming the fault was a single-phase high-resistance joint defect on Phase B with no open-circuit condition.

Step 3: High-Voltage Arc Reflection

DC high-voltage was applied to Phase B. At 50 kV the fault broke down. The test configuration was adjusted with the 5-50kV transformer and two 40-6 capacitors in parallel, sphere gap calibrated to 32 kV. Using the flashover sampling method, the fault distance was calculated at 7.1 km from the substation — a clear inflection point on the captured waveform.

Step 4: Precision Pinpointing

The crew used a measuring wheel from the substation and worked back from the 7 km mark, pinpointing approximately 200 meters toward the substation. At the fault location, the acoustic discharge from the XHDD503 Pinpointer was audible at ground surface without headphones — confirming a strong pinpoint signal directly above the fault.

Key Findings

• Joint position markers deviated significantly from actual locations — unreliable for long cable runs.
• Measuring wheel straight-line distance differs from actual cable laying path; longer runs accumulate greater error.
• Strong grassland winds affected acoustic judgment, making the XHDD503's powerful output signal critical for reliable detection.
• For a 7.1 km fault on a 14.8 km cable, the search range needed to extend 100–150 m toward the feed point.

Conclusion

The XZH TEST fault location system — XHGG502 Pre-Locator, XHDD503 Pinpointer, and HV DC test set — successfully identified a 35kV high-resistance cable joint fault at Sidrap Wind Farm, Indonesia. Systematic multi-stage methodology (LVP pre-location, HV arc reflection, acoustic pinpointing) delivered an accurate 7.1 km fault distance for single-excavation repair, minimizing turbine downtime in a revenue-critical wind generation environment.