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Ghaffarian Niasar, M. (author), Wang, Xiaolei (author), Kiiza, Respicius Clemence (author)When detecting the presence of partial discharge (PD) activity in the insulation system in high-voltage equipment, the excitation voltages at variable frequency have been widely used instead of power-frequency (50/60 Hz) sinusoidal voltage in order to reduce the charging power. This work reviews the relevant research on PD activity at very low...journal article 2021
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Mier Escurra, C. (author), Mor, A. R. (author)Gas insulated substations (GIS) have increased in the electric power system in recent years and is expected to continue increasing in the following years. The GIS has remarkable advantages over air insulated substation in offshore windfarms where the installation space is limited. The outlying location of the GIS demands a robust monitoring...conference paper 2021
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Abdul Madhar, S. (author), Brunner, Marc (author), Mor, A. R. (author), Mraz, Petr (author)The discharge over dielectric interfaces popularly known as surface discharge is a very common defect type that is associated with its respective discharge pattern under AC voltages. However, the same designs behave differently under DC voltages leading up to erratic PD behavior. To understand the process of surface discharge an equivalent...conference paper 2021
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Ganeshpure, D.A. (author), Castro Heredia, L.C. (author), Ghaffarian Niasar, M. (author), Vaessen, P.T.M. (author), Soeiro, Thiago B. (author), Bauer, P. (author)This paper presents a comparison in Partial Discharge (PD) behaviour when an air corona setup is subjected to different waveforms, namely an idealized 50 Hz sinusoidal and staircase-based sinusoidal waveforms near inception voltage and at a higher voltage. In this study, it has been observed that the PD repetition rate and the Phase-Resolved PD ...conference paper 2021
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Kulkarni, Devendra (author)The Medium Voltage (MV) network in the Netherlands is almost entirely composed of underground cables. The failure statistics show that the interruptions in the medium voltage have a high contribution in the mean outage time per year per customer. The interruptions in the medium voltage grid are often caused by failure of circuit components...master thesis 2020
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Abdul Madhar, S. (author), Mraz, Petr (author), Mor, A. R. (author), Ross, Robert (author)This paper presents several approaches to the analysis of partial discharge (PD) data. Three common defects namely corona, surface and floating electrode are studied with the goal of defect identification under DC stress conditions. One of the major concerns with DC-PD testing, is its non-repetitive/erratic pulse pattern. This paper, however,...journal article 2020
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Muñoz Muñoz, F.A. (author), Mor, A. R. (author)This paper presents a wavelet analysis technique together with support vector machines (SVM) to discriminate partial discharges (PD) from external disturbances (electromagnetic noise) in a GIS PD measuring system based on magnetic antennas. The technique uses the Cross Wavelet Transform (XWT) to process the PD signals and the external...journal article 2020
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Abdul Madhar, S. (author), Mraz, Petr (author), Mor, A. R. (author), Ross, Robert (author)Corona is one of the most common forms of partial discharge (PD) occurring in high voltage (HV) energy systems. The corona mechanism in air is not exclusive to the field of energy applications but has also been widely studied by physicists to theorize mechanisms of charge transfer during the different phases of gas discharge. The phases of the...journal article 2020
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Castro Heredia, L.C. (author), Mor, A. R. (author), Wu, J. (author)The problem of impaired data sets refers to data sets containing a vast majority of unwanted signals than signals of interest. With increased interest in partial discharge (PD) testing with arbitrary waveforms and transients, these kind of data sets are becoming more and more common. Traditional clustering techniques cannot be applied due to big...journal article 2020
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Morette, N. (author), Castro Heredia, L.C. (author), Ditchi, Thierry (author), Mor, A. R. (author), Oussar, Y. (author)This paper tackles the problem of the classification of partial discharge (PD) and noise signals by applying unsupervised and semi-supervised learning methods. The first step in the proposed methodology is to prepare a set of classification features from the statistical moments of the distribution of the Wavelet detail coefficients extracted...journal article 2020
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Mor, A. R. (author), Muñoz Muñoz, F.A. (author), Castro Heredia, L.C. (author)This paper describes a simplified model and a generic model of high-frequency current transformer (HFCT) sensors. By analyzing the models, a universal charge estimation method based on the double time integral of the measured voltage is inferred. The method is demonstrated to be valid irrespective of HFCT sensor, assuming that its transfer...journal article 2020
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Wu, J. (author), Smit, J.J. (author), Mor, A. R. (author)In practice, High-voltage (HV) cables are occasionally exposed to impulse and superimposed transient conditions, which may initiate partial discharges (PD) temporarily. Whether such PDs persist under AC voltage after the transient conditions have vanished, is at focus in the research described in this paper. Since for cross-linked polyethylene ...journal article 2020
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Abdul Madhar, S. (author), Mraz, Petr (author), Mor, A. R. (author), Ross, Robert (author)Partial discharge is a prevalent phenomenon under high voltage (HV) where the discharge partially bridges the gap between two electrodes. At increasing voltage levels, physical dimensions and distances between the electrical parts become critical. Designing electrical components for such high voltages and planning of high voltage laboratories...journal article 2019
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Mor, A. R. (author), Muñoz Muñoz, F.A. (author), Wu, J. (author), Castro Heredia, L.C. (author)This paper presents a new wavelet analysis approach in partial discharges cable joint measurements in noisy environments. The proposed technique uses the Cross Wavelet Transform (XWT) to separate PD signals from noise and external disturbances in partial discharges measurements in cable joints using two opposite polarity sensors. The partial...journal article 2019
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Wu, J. (author), Mor, A. R. (author), van Nes, P.V.M. (author), Smit, J.J. (author)A partial discharge (PD) measuring system has been deployed in order to identify and measure PD in a high voltage (HV) cable joint under impulse and superimposed voltages under laboratory conditions. The challenge is to enable the detection of PD during the impulse conditions. The method of measurement has been investigated by introducing an...journal article 2019
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Mor, A. R. (author), Castro Heredia, L.C. (author), Muñoz Muñoz, F.A. (author)This paper presents a magnetic loop antenna for partial discharge (PD) measurements on gas insulated systems (GIS). The antenna is based on a single shielded loop inserted in the dielectric window of a GIS that measures the PD currents propagating in TEM mode. The paper describes the relevant parameters of the antenna and the antenna...journal article 2019
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Abdul Madhar, S. (author), Mraz, Petr (author), Raquel Barrios Pereira, Sonia (author), Akroud, Nabil (author)Asset condition monitoring through Partial Discharge (PD) measurements is widely used for pre-emptive maintenance especially in cable networks. Several monitoring systems rely on measurements in the High Frequency (HF) band using wideband sensors when it comes to PD monitoring to have higher Signal to Noise Ratios (SNR), ignoring the radical...conference paper 2019
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Castro Heredia, L.C. (author), Mor, A. R. (author)The recognition of partial discharge (PD) sources is an important task of the monitoring and diagnostics of high-voltage components. Nowadays, digital PD measuring systems have the capability of extracting features and form scatter plots with such data sets. Part of an unsupervised PD analysis system is to discover clusters within the data...journal article 2019
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Mor, A. R. (author), Muñoz Muñoz, F.A. (author), Castro Heredia, L.C. (author)This paper presents a new concept for partial discharge measurements in gas insulated systems (GIS). The proposed technique uses a novel GIS magnetic antenna that measures the magnetic field produced by partial discharges (PD) propagating in GIS. The foundations of the measurement technique and the magnetic antenna design are presented...journal article 2019
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Wu, J. (author), Mor, A. R. (author), Smit, J.J. (author)In practice, cross-linked polyethylene (XLPE) power cables can be subjected to alternating voltage with superimposed impulse transients. Such impulse transients may initiate partial discharges (PD) in insulation defects even below AC inception voltage. An initiated PD may persist under AC, which will cause insulation degradation. This paper...journal article 2019