Transformer oil paper insulation dielectric response and paraffin content correlation evaluation method

Abstract

The invention discloses a transformer oil paper insulation dielectric response and paraffin content correlation evaluation method. The transformer oil paper insulation dielectric response and paraffincontent correlation evaluation method comprises the steps of establishing an experiment platform, preparing oil-immersed transformer XY model samples with different paraffin content and different voltage levels, testing frequency domain dielectric spectra of XY model samples with different paraffin contents at different low temperatures, acquiring dielectric response curves of different paraffincontent, establishing a mathematical model by combining a slope at an ''inflection point'' of dielectric loss and a minimum frequency test value, proposing paraffin content evaluation indexes, and establishing a paraffin content evaluation index expert database. Through testing frequency domain dielectric spectra of an oil-immersed transformer on site under a high and cold condition and recordingambient temperature, the corresponding test curve is obtained, the mathematical model obtained in a laboratory is combined, the on-site paraffin content evaluation indexes are extracted and compared with the paraffin content evaluation index expert database, thus the paraffin content of the oil-immersed transformer under the high and cold conditions can be effectively evaluated, and a guidance method is provided for accurately evaluating the oil-paper insulation state 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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