Fuzzy Logic Based Calculation and Analysis of Health Index for Power Transformer Installed in Grid Stations

The health index calculation is a very useful tool for power transformer maintenance prediction. Generally, transformer health condition is directly assessed by diagnostic tests carried out for the transformer insulation. Then these test results are used to evaluate health and to estimate the remaining life of the transformer. By using different parameters of the transformer, the Health Index shows the degradation of insulation in the transformer. These parameters of the transformer typically act at the identical time, due to this reason evaluation of health index of the transformer is very difficult. In this paper different parameters are utilized to create sub-models of fuzzy (i.e. DGA, Dielectric strength of oil, loading data, insulation resistance, C&DF) for assessment of transformer critical conditions. The integrated fuzzy model developed by combining the sub-models of fuzzy logic. This model of fuzzy logic provides the identification of transformer insulation condition & level of its criticality. The integrated fuzzy model approach decreases the complexity in life estimation and health index evaluation of power transformer. With the help of the health index, it can be determined the transformer health condition and can be taken the necessary remedial action to save the costly equipment at grid stations to overcome the occurrence of severe equipment damaging faults.