Calculation the dissipation factor of power transformers insulation system using genetic algorithm

Dialectical properties of power transformer system change during its operation. Therefore, transformers should necessarily be measured to detect their aging. Nowadays there are some experiments for identifying status of paper-oil insulation in transformers and they are done in time and frequency domains. This article investigates relationship between time and frequency domain experiments and shows these two experiments are well correlated. Using polarization and depolarization current method (PDC) which it belongs to time domain and estimating parameters of insulation model by genetic algorithm leads to plot dissipation factor (tan δ) in term of frequency.