Keywords
relaxation circuits
recovery voltage
power cable
spectra of recovery voltage curves
wavelet transform
delayed absorption processes
insulation humidification
thermal aging
criteria for assessing the state of inhomogeneous insulation неоднорідна двошарова ізоляція
релаксаційні ланцюжки
відновлювальна напруга
силовий кабель
спектри кривих відновлювальної напруги
вейвлет-перетворення
уповільнені абсорбційні процеси
зволоження ізоляції
теплове старіння
критерії оцінки стану неоднорідної ізоляції
How to Cite
Abstract
Based on the proposed model of spatially inhomogeneous two-layer insulation in the form of a series-parallel substitution scheme with three relaxation chains, the calculated recovery voltage curves of phase and belt paper-impregnated insulation of power cables are obtained. The model was verified by comparison with the experimental voltage curve of the power cable with paper-impregnated insulation at a voltage of 6 kV. The possibility of separation of delayed absorption processes in inhomogeneous insulation is substantiated on the basis of the analysis of high-frequency components of the spectrum of time dependences of the recovery voltage curves. The effectiveness of wavelet transform for detailing the absorption characteristics of inhomogeneous insulation of power cables is confirmed. The presence of two maxima and the dynamics of change of the ratio between them in the process of aging of inhomogeneous insulation on the reproducible curves of the regenerative voltage of power cables are established. Based on the relationship between the two amplitude values of the reproducible reduction voltage, the preferred absorption processes are determined and the appropriate criteria for assessing the state of inhomogeneous insulation of power cables are established. References 16, figure 5.
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