Why is DC hipot not recommended for XLPE cables?

DC creates space charges in XLPE that don't reflect true AC performance and can damage healthy insulation. IEEE 400.2 recommends VLF or AC methods for XLPE. DC remains appropriate for PILC cables.

When should HV cables be tested?

At commissioning, after joint/termination work, periodically as condition monitoring (5–10 year cycle), after civil works near the route, and for post-fault investigation.

Can Megavar locate underground cable faults?

Yes. TDR estimates fault distance, then thumper/acoustic pinpointing locates the fault to within metres on the ground.

Does Megavar test cables nationally?

Yes. We deploy from Tasmania, SA, NSW, and ACT offices to all states and territories.

HV Cable Testing Services Australia

Verify the Integrity of Your High Voltage Cable Systems

Underground HV cables are critical and often inaccessible. A failure results in extended outages, expensive excavation, and significant consequential costs. Megavar provides comprehensive cable testing for XLPE, EPR, and PILC cables from 11 kV to 220 kV across Australia.

VLF Withstand Testing

VLF applies sinusoidal AC at 0.1 Hz above operating voltage to identify weakened insulation. The preferred acceptance method for XLPE cables per IEEE 400.2, avoiding space-charge damage caused by DC hipot.

VLF Partial Discharge Testing

Combined VLF withstand and PD measurement for the most comprehensive cable assessment. PD source location along the cable enables targeted investigation of defective joints, terminations, or sections.

DC Insulation and Hipot

Basic insulation assessment. DC hipot appropriate for PILC cables; VLF preferred for XLPE.

Sheath Integrity Testing

DC voltage between sheath and earth verifies outer protection. Sheath defects allow moisture ingress causing water treeing. Essential after installation, jointing, and civil works.

Tan Delta Testing

Cable insulation dissipation factor assessment for moisture, ageing, and degradation. Valuable for trending deterioration in aged XLPE and EPR cables.

Cable Fault Location

TDR (time-domain reflectometry) and thumper/acoustic methods locate faults to within metres, minimising excavation and repair time.

Frequently Asked Questions
HV Cable Testing Services Australia

What is VLF cable testing?

VLF (Very Low Frequency) testing applies a 0.1 Hz sinusoidal voltage to medium and high voltage cables to test insulation integrity. It is used for commissioning new cable installations, periodic maintenance testing, and fault diagnosis. VLF is the preferred method for testing XLPE and EPR cables.

What voltage levels can Megavar test cables to?

Our VLF test sets can apply up to 60 kV peak (testing cables rated up to 36 kV). For higher voltage cables, we use resonant test systems capable of testing cables rated up to 220 kV.

Can Megavar perform partial discharge testing on cables?

Yes. Megavar provides both online and offline partial discharge (PD) testing for HV cables, detecting localised insulation defects before they develop into full insulation failure.

How often should HV cables be tested?

New cables should be tested before energisation. For in-service cables, many asset owners adopt a 3 to 5 year testing cycle, with more frequent testing for critical circuits or cables showing signs of deterioration.

What is included in a cable testing report?

Yes. Megavar can mobilise to locate faults using VLF testing, time domain reflectometry (TDR), and acoustic/electromagnetic pinpointing techniques.

Does Megavar provide cable fault location services?

Every cable test report includes the test method and equipment used, applied voltage levels and duration, leakage current measurements, partial discharge results (if applicable), pass/fail assessment, and recommendations for remedial action.

Ready to commission your substation? Contact Megavar today on 1300 730 499 or visit our contact page to request a quote.

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