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Safe operation of electrical power network relies on healthy electrical insulation of all of its components. In general, the condition of insulation is unknown and appropriate periodic electrical testing is required to detect potential deterioration and avoid catastrophic failure of the given system.
Modern technology and developments in signal acquisition and analysis techniques have provided new tools for transformer diagnostics. Of particular interest are Dielectric Response Measurements, DFR (also known as Frequency Domain Spectroscopy, FDS), a tool for investigating insulation properties of specific materials and material combinations, e.g., oil-paper systems.
Dielectric Frequency Response, DFR (also known as Frequency Domain Spectroscopy, FDS), was introduced more than 20 years and has been thoroughly evaluated and proven in a number of research projects as and field tests with good results. DFR data in combination with mathematical modeling of the oil-paper insulation is proven as an excellent tool for understanding insulation properties e.g. moisture...
Sweep frequency response analyzer (SFRA) measurements are now an established method for condition assessment of power transformers. Since most of evaluation procedures is based on comparison between; 1) earlier measurements on same transformer, 2) measurements on sister transformers, or 3) phase to phase comparison on same transformer, the measurement accuracy and repeatability is of utmost importance...
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