Effective analysis of time‐domain dielectric response for reliable diagnosis of power transformer insulation using statistical parameter evaluated from time‐varying model.

Various types of insulation models with time‐invariant parameters are available in the literature. Depending on the aging sensitive performance parameters to be evaluated, different models need to be employed (e.g. XY model for oil and paper‐conductivity, conventional Debye model (CDM) for paper‐moisture and tanδ). While the XY model cannot be used for estimating paper‐moisture directly, analysis based on CDM parameter becomes dependent on its branch parameters, which are non‐unique. These factors lead to either incomplete or ambiguous insulation diagnosis. These problems are resolved using the proposed new insulation model containing unique time‐varying branch parameters. Another major advantage of the proposed model is that it can be used to evaluate a host of performance parameters (like paper‐conductivity, oil and paper‐moisture, dielectric loss) thus giving a complete picture of the insulation concerned. The application of the proposed model is also tested on data collected from several real‐life power transformers. [ABSTRACT FROM AUTHOR]