When should cable oil replacement be considered in maintenance routines?

Oil replacement should be considered when:

Severe Degradation: Oil cannot be restored through purification or regeneration.
Contamination Levels: High levels of contaminants like metals, acids, or sludge.
Dielectric Failure: Oil fails to meet minimum dielectric strength requirements.
Chemical Changes: Significant alteration in oil composition or additive depletion.
Manufacturer Recommendation: Based on operating hours or condition assessments.
Timely replacement prevents cable failures and ensures reliable power transmission.