Cable oil testing involves:

Sampling: Collecting oil samples from the cable system using clean, contamination-free methods.
Laboratory Analysis: Performing tests such as dielectric breakdown voltage, moisture content (Karl Fischer titration), acidity (neutralization number), and dissolved gas analysis (DGA).
Data Interpretation: Comparing results against standard values or historical data to assess degradation or contamination levels.
Reporting: Providing recommendations for maintenance actions based on test results.
Regular testing helps in early detection of issues, enabling timely maintenance.