Oil paper insulation dominant time constant calculation method based on extended Debye equivalent circuit

Abstract

An oil paper insulation dominant time constant calculation method based on an extended Debye equivalent circuit sequentially comprises the following steps: the step 1, performing preparation work comprising powering off a transformer to stop operation, enabling various phases of high- and low-voltage windings and a neutral point to be in short connection and be grounded, and then releasing residual charges; the step 2, obtaining data comprising setting a polarization voltage and a charging and discharging time ratio, performing wiring, and performing a recovery voltage test experiment on the transformer by utilizing an RVM5461; the step 3, selecting a shuffled frog leaping algorithm, and establishing an evaluation function to solve an equivalent circuit parameter; the step 4, calculating peak value measurement time through adoption of segmented Hermit interpolations for 3 times, and obtaining a continuous recovery voltage polarization spectrum according to a recovery voltage calculation formula; and the step 5, searching a peal value of the recovery voltage polarization spectrum to determine a dominant time constant. The problem of insufficient accuracy of a non-standard polarization spectrum dominant time constant in actual measurement and the problem of long consumed time in the actual measurement are overcome, and accuracy of diagnosing a moisture content of an insulation system by utilizing the dominant time constant is improved.

Description

technical field [0001] The patent of the invention relates to the technical field of transformer oil paper insulation state evaluation and life prediction, especially the calculation method of continuous recovery voltage polarization spectrum and principal time constant based on extended Debye equivalent circuit. Background technique [0002] Power transformers are responsible for the conversion and transportation of electric energy in the power system. Once an insulation fault occurs, it will not only affect the reliability of power supply, but also lead to the end of the life of the transformer and cause huge economic losses. Long-term work under the combined action of electric and thermal fields will cause transformer insulation to age. Moisture is not only an aging product, but also causes a decrease in the breakdown voltage of the insulating oil, an increase in the dielectric loss factor and accelerated aging of the insulating oil. Generally speaking, the transformer Oi...

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Problems solved by technology

[0005] In view of the above problems, the purpose of the patent of this invention is to provide a method for calculating the main time constant of oil-paper insulation based on the extended Debye equivalent circuit, which aims to solve the problem that the measured polarization spectrum is not With a single peak, the problem of undetermined master time constant

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