Benchmarking and Lifecycle Risk Analysis of HV Cables

With the recent growth in high-voltage electrical network construction across Australia, HV cable testing and long-term analysis have become more critical than ever. Asset owners are now focused on benchmarking and forecasting the condition of their HV cables to develop efficient, long-term maintenance and intervention plans. Effective condition monitoring from day one is essential, starting with diagnostic commissioning tests.

Failure Mode Analysis for Effective HV Cable Testing

The first step in any HV cable testing program is understanding potential failure modes. HV cables have multiple failure modes that can arise at different stages of their lifecycle. Table 1 below outlines common failure modes for both PILC and XLPE cables.

Table 1 – Cable type and Common Failure Modes

The three main stages where defects in the HV cable lifecycle can occur are:

1. Manufacturing
2. Commissioning
3. Operation

A 2024 IEEE study found that workmanship defects are the root cause of 57% of HV cable failures, while manufacturing defects account for 16% (9% in cables, 7% in accessories). These insights reinforce the importance of thorough testing during the commissioning stages.

Figure 1 – Ultimate cause of HV Cables Failures

Figure 2 – Age of failures over cable life cycle

Since most HV cable defects are introduced before or during commissioning, well-designed commissioning testing is essential to identify these issues early and mitigate long-term risks. Not all defects lead to immediate failure; many cause slow deterioration, resulting in cable failure years later.

Commissioning and Benchmarking in HV Cable Testing

Commissioning testing traditionally involves withstand-style acceptance tests that provide pass/fail results, standardising initial safety and reliability assessments. According to the IEEE 400.2-2023 guidelines, these tests include installation and integration testing before cables go into service.

While withstand testing is valuable for identifying initial issues, it lacks trendable data needed for long-term condition monitoring. Benchmark testing during HV cable commissioning provides comprehensive diagnostics, allowing asset managers to establish a baseline for future condition monitoring.

EA Technology recommends a complete test suite during commissioning, including:

• VLF Withstand - IEEE 400.2-2013
• VLF Tan Delta - IEEE 400.2-2013
• VLF Partial Discharge - IEC 60270-3 / IEEE 400.3

Additional testing like Line Impedance Resonance Analysis (LIRA) can be conducted offline, while online partial discharge testing immediately after energisation provides coverage for components not tested offline, such as terminations and connections.

These tests give asset managers high confidence in identifying any defects along an HV cable run, enabling immediate intervention if necessary. They also allow tracking of low-level defects for long-term condition monitoring, supporting predictive maintenance efforts.

Forecast Network Risk: Proactive Risk Management for HV Cables

Once initial benchmarking is complete, long-term risk management and planning become essential. By collecting comprehensive data, such as cable type, manufacturer, and condition through repeat HV cable testing (online and offline), asset owners can forecast the health and degradation of HV cables over their lifecycle. This predictive approach enables informed maintenance planning based on cable conditions.

Optimising HV Cable Lifespan Through Benchmarking

To optimise HV cable lifespan, acquiring high-quality condition monitoring data from the outset is essential. EA Technology recommends diagnostic PD, Tan Delta, and LIRA tests for all commissioning programs. These provide in-depth benchmarks for all future condition monitoring, enabling effective predictions of asset health. Learn more about our Cable Condition Assessment and Partial Discharge Monitoring Service for comprehensive HV asset support.

Frequently Asked Questions (FAQs)

1. What is HV cable testing?
   It is an assessment of cable conditions through methods like partial discharge, Tan Delta, and LIRA to detect potential faults early.
2. Why is benchmarking important in HV cable testing?
   Benchmarking establishes a baseline for future tests, allowing asset managers to track degradation and plan effective maintenance.
3. How does the CableData® Collector enhance predictive maintenance?
   The CableData® Collector enables predictive maintenance by collecting trendable data to identify potential issues before they escalate.
4. What tests are included in HV cable commissioning?
   Commissioning tests include VLF Withstand, VLF Tan Delta, VLF Partial Discharge, and LIRA, covering all aspects of cable health.
5. How can I get more information on HV cable testing?
   For more details on our HV cable testing services, contact our team to discuss your needs.