Dielectric response analysis and diagnosis of oil-filled power transformers calculation of paper moisture in power transformer

All the manufacturers of power transformer give the anticipated life of their product in terms of certain numbers of years. Some power transformers may fail earlier than their stipulated life, while some of them even may cross their limit of recommended age and they are still in working status. But the transformers which are in working condition after their completion of expected age or near to complete their expected age, normally need more care and precautions. For this, some important tests are involved more often in a regular fashion to determine the health status. These tests include moisture level determination in paper insulation, moisture level in oil insulation, BDV, flash point, acidity, tan delta (dissipation factor) measurement and IFT etc. and adopt the recommendation and precautionary action to avoid major faults. In this report, a survey of three power transformers (21 year old) of HPSEBL, Shimla has been performed on the basis of DIRANA (Dielectric Response Analyzer) wherein details related to its paper insulation moisture diagnostics have been taken as preventive measure to safeguard the equipment.