Systematic Approach for Condition Assessment of Dry-Type Transformers based on Partial Discharge Measurements

While dry-type transformers offer certain benefits over oil-filled units, the lack of oil prevents the use of dissolved gas analysis (DGA) as a commonly used tool for insulation condition assessment. The partial discharge (PD) measurement of in-service units has proven to be a powerful tool to fill that gap, but proper interpretation and assessment of risk is more difficult, as there is a lack of comprehensive guidelines for proper assessment of such a complex subject.