PROJECT TITLE :

Quantitative evaluation of ageing condition of oil-paper insulation using frequency domain characteristic extracted from modified cole-cole model

ABSTRACT:

The service life of a transformer is decided by the condition of its oil???paper insulation. A modified Cole???Cole model was introduced to describe the frequency domain spectroscopy (FDS) curves primarily based on the classic Debye relaxation model and thereby accurately determined the ageing state of the insulation of an influence transformer using FDS. Oil???paper insulation samples with totally different ageing states are ready underneath laboratory conditions, and a characteristic parameter is extracted to quantify their ageing states when a detailed investigation of the frequency domain dielectric properties of the samples. Results reveal that the changed Cole???Cole model, including the ?? relaxation components, dc and hopping conductivity parts, will be utilized to effectively model the frequency dielectric characteristics of oil???paper insulation. Furthermore, the extracted characteristic parameter from this model, ????, can be utilized within the quantitative evaluation of the ageing states of transformer insulation. A case example is mentioned to demonstrate the applicability of the proposed technique within the condition assessment of field power transformers.