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partial-discharge--pd
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Investigation of high frequency signal propagation characteristics on HV XLPE cables
, Article 7th International Power Engineering Conference, IPEC2005, Singapore, 29 November 2005 through 2 December 2005 ; Volume 2005 , 2005 ; 9810544693 (ISBN); 9789810544690 (ISBN) ; Blackburn, T. R ; Phung, B. T ; Vakilian, M ; Naderi, M.S ; Zhang, H ; Sharif University of Technology
2005
Abstract
The insulation lifetime of power cables is determined by several factors. One of the more important of these is the occurrence of partial discharge (PD) at the dielectric. The ability to detect and locate a PD source is limited by attenuation of the high frequency PD pulses as they propagate through the cable. Therefore it is necessary to understand the high frequency response of such cables. Further, to enable reconstruction of PD signals as emitted a viable high frequency model for simulation is needed. This paper presents results of measurements of PD calibration pulse and high frequency sinusoid propagation in HV XLPE cables. In addition to the tests a cable model was developed using the...
Analysis of partial discharge by eavelet-hilbert transform
, Article European Transactions on Electrical Power ; Volume 19, Issue 8 , 2009 , Pages 1140-1152 ; 1430144X (ISSN) ; Reihani, E ; Nabizadeh, N ; Hooshmand, A ; Davodi, M ; Sharif University of Technology
2009
Abstract
Time-frequency and time-scale transforms are one of the powerful mathematical methods for feature extraction of non-stationary signals such as partial discharge (PD) signals. Modified Fourier-based transforms and Wavelet transforms are well known among them. PD signals can be analyzed by these influential methods but normally with some serious limitations and inadequacies. This paper proposes a new approach based on Wavelet-Hilbert transform for the analysis of electrical PD signals. The mathematical model of a Wavelet-Hilbert transform is described. Contemplating of natural behavior of PD, that is, stochastic and non-stationary an artificial multi-source of PD is simulated in a Detail model...
HTS transformer’s partial discharges raised by floating particles and nitrogen bubbles
, Article Journal of Superconductivity and Novel Magnetism ; Volume 33, Issue 10 , 6 July , 2020 , Pages 3027-3034 ; Vakilian, M ; Hekmati, A ; Fardmanesh, M ; Sharif University of Technology
Springer
2020
Abstract
Presence of defects, conducting particles, nonconducting particles, and nitrogen gas bubbles in the insulation system of high-temperature superconducting (HTS) transformers, mainly inside the liquid nitrogen as its major insulation, can create local field enhancement and consequently partial discharges which eventually lead to the catastrophic failure of the transformer. In this paper, two-dimensional (2D) axisymmetric finite element method (FEM) modeling via COMSOL Multiphysics software has been utilized for the investigation of the impact of size and shape of conducting particles and nitrogen gas bubbles on partial discharge (PD) activities in liquid nitrogen. Conducting particles of...