Abstract
Frequency domain spectroscopy (FDS) technique is widely applied in the condition assessment of the oil-paper system in power transformers. However, the synergistic effect generated by moisture and temperature on the FDS data cannot be analyzed by the existing model since the single independent variable (moisture or temperature) is considered in the construction of the model. To quantify such the synergistic effect, a novel method that utilized for normalizing (or standardizing) the FDS curve is reported based on the theory of the power series and fitting analysis. The present findings reveal that the reported method is capable of predicting the dielectric loss (tanδ) curve under diverse test conditions, in which the average error is less than 7%. The synergistic effect can be also explored by using the extracted feature parameters. The potential application is then proved to make up for the measurement errors during the FDS test, the findings are expected to promote the moisture analysis of the transformer insulation.
Highlights
The oil-paper system, as the main high-voltage insulation system inside power transformer, will be gradually aged in the long-term service due to the influence of multiple stresses, such as thermal field and electric field [1]-[2]
The present findings reveal that the reported method is capable of predicting the dielectric loss curve under diverse test conditions, the obtained average error is less than 7%
The prediction of the normalized Frequency domain spectroscopy (FDS) curve It is worth to note that the model coefficients Фij (j=0, 1, 2, 3) under different temperatures and moisture can be calculated by using Table III, which means that the normalized FDS curves can be further calculated by using Equation (4)
Summary
The oil-paper system, as the main high-voltage insulation system inside power transformer, will be gradually aged in the long-term service due to the influence of multiple stresses, such as thermal field and electric field [1]-[2]. It is pointed out that the contribution of moisture and temperature to the FDS would be inevitably contained in the collected FDS [24]-[25] In this case, the results of the condition evaluation of transformer insulation will be unreliable once the mentioned synergistic effect generated by moisture and temperature on the collected FDS is ignored. Provided that the FDS data can be simulated (or normalized) by the defined parameters contained in the equivalent models (or equations), the quantitative analysis of the synergistic effect generated by moisture and temperature on the FDS data can be realized. In view of the above issues, depending on the theory of the power series [29], a novel method that utilized for normalizing the FDS curve of transformer oil-immersed insulation is reported. The present contributions are expected to promote the moisture analysis of the transformer insulation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
