Evaluation method for correlation between dielectric response of transformer oil-paper insulation and paraffin content

Abstract

The invention discloses a method for evaluating the correlation between the dielectric response of transformer oil-paper insulation and paraffin content. The method prepares XY model samples of oil-immersed transformers with different paraffin content and different voltage levels by building an experimental platform, and tests the performance at different low temperatures. The frequency-domain dielectric spectrum of XY model samples with different paraffin content is used to obtain the dielectric response curves of different paraffin content. Combined with the slope of the dielectric loss "inflection point" and the lowest frequency test value, a mathematical model is established, and the paraffin content evaluation index is proposed. Content evaluation index expert database. Through on-site testing of the frequency-domain dielectric spectrum of oil-immersed transformers under alpine conditions, recording the ambient temperature, obtaining the corresponding test curves, combining with the mathematical model obtained in the laboratory, extracting on-site paraffin content evaluation indicators, and comparing them with the paraffin content evaluation index expert database, It can effectively evaluate the paraffin content of oil-immersed transformers under alpine conditions, and provide guidance methods for accurate evaluation of oil-paper insulation status and troubleshooting in actual engineering.

Description

technical field [0001] The invention belongs to the field of insulation evaluation and diagnosis of oil-immersed transformers, and in particular relates to a method for evaluating the correlation between the dielectric response of transformer oil-paper insulation and paraffin content. Background technique [0002] With the maturity of UHV power transmission technology, several UHV projects will be constructed in cold regions such as Northeast China, Inner Mongolia and Xinjiang. In addition, with the introduction of the concept of the Global Energy Internet, it is possible to transmit electricity from clean energy bases such as "one pole and one road" through UHV power transmission technology, and the lowest temperature in the Arctic has reached -68°C. The large oil-immersed power transformer is the core part of the power system. Its insulation status determines whether the power grid can operate safely. During severe cold weather, oil-immersed transformers have been found to...

AI Technical Summary

Problems solved by technology

However, when the dielectric spectrum curve of the oil-immersed transformer is tested on the spot under the extreme cold condition, the connection between the spectrum and the paraffin content has not been established, there is no evaluation method for the paraffin content in the oil-immersed transformer under the extreme cold condition, and the oil-immersed transformer cannot be realized. Accurate assessment of the insulation state

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