Improved Moisture Analysis of Power Transformers Using Dielectric Response Methods
نویسنده
چکیده
This paper starts with a systematic benchmark test of the three commercialised dielectric diagnostic methods RVM (recovery voltage method), PDC (polarisation and depolarisation currents) and FDS (frequency domain spectroscopy), performed on a large transformer model. Starting from the explored strengths and weaknesses a more sophisticated instrument with corresponding software was developed. The new instrument called “Dirana” combines time and frequency domain measurements resulting in an essentially decreased measurement time. The corresponding software bases on a new data pool, measured at new and aged pressboard with various moisture contents, temperatures and oil impregnation. The analysis algorithm works in frequency domain and features weighting of low frequency data and compensation for conductive aging byproducts. An onsite moisture evaluation compares the new system to other measurement methods.
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