When should silicone oil replacement be considered in transformer maintenance routines?

Silicone oil replacement should be considered when the oil has degraded beyond the point where purification or regeneration can restore its properties. Indicators for replacement include consistently low dielectric strength, high acidity levels, excessive moisture content, and significant particulate contamination. If the oil fails to meet the required performance standards after treatment, or if it’s contaminated with substances that cannot be removed effectively, replacement is necessary to maintain transformer safety and functionality.