access icon free Estimation of paper-moisture in transformer insulation employing dielectric spectroscopy data

© The Institution of Engineering and Technology
Received 04/10/2017, Accepted 19/02/2018, Revised 29/01/2018, Published 20/02/2018

Accurate estimation of paper-moisture in transformer insulation is necessary for ensuring their satisfactory operation. Paper-moisture in transformer insulation can be estimated from their corresponding transfer function zero obtained from insulation model that is parameterised using polarisation depolarisation current data. However, paper-moisture estimated using transfer function zero is less reliable for a new unit. Considering the fact, a method is proposed in this work that can estimate the paper-moisture with greater accuracy. Instead of using only transfer function zero, tanδ has also been employed for estimating the paper-moisture. In order to investigate the effectiveness, the proposed technique has first been applied on several test samples in the laboratory. The proposed technique is then applied on few power transformers to estimate their paper-moisture. Results obtained from the experiment show that this technique can estimate the paper-moisture content within test samples and power transformer insulation with better accuracy.

Inspec keywords: power transformer insulation; moisture measurement; power transformer testing; paper

Other keywords: polarisation depolarisation current data; dielectric spectroscopy data; power transformer insulation estimation; paper-moisture estimation; transfer function zero

Subjects: Organic insulation; Humidity measurement; Transformers and reactors; Hygrometry

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