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.