Yazar "Kumru, Celal Fadil" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • Küçük Resim Yok
    Öğe
    The Effects of Overvoltage Aging on 20 kV XLPE Power Cable
    (IEEE, 2019) Uydur, Cihat Cagdas; Arikan, Oktay; Kucukaydin, Baris; Dursun, Bekir; Kumru, Celal Fadil
    XLPE power cables have been widely used with the development of city power grid because of their obvious advantages. To improve the reliability of power supplies and meet the requirements of urban landscaping, however, faults in the electricity distribution grid and load/demand imbalance cause degradation in underground cables. This degradation leads the cable to be aged and reduce its lifetime. Therefore, it is important to examine the behavior of the XLPE insulated cable dielectric parameters. In this study, a 12/20 kV XLPE cable was aged using 60 kV overvoltage and this voltage was applied to the test samples for 15 minutes intervals. 80 cycles of aging were carried out and dissipation factor (tan delta), dielectric losses (P-k) and partial discharge (PD) measurements were performed after each aging cycle. OMICRON CPC100/CPTD1 was used to measure dissipation factor (tans), dielectric losses (Pk) and OMICRON MPD600 was used to measure partial discharge.
  • Küçük Resim Yok
    Öğe
    Insulation evaluation of MV underground cable with partial discharge and dielectric dissipation factor measurements
    (Elsevier Science Sa, 2023) Arikan, Oktay; Uydur, Cihat Cagdas; Kumru, Celal Fadil
    As it is known overvoltage and impulse voltage are the most common stresses that cables are exposed to in practice. Since the occurrence frequency, duration and amplitude of these two stresses are different, their deteriorating effects on the cable insulation also differ. At this point, it is necessary to know how sensitively the preferred dielectric diagnosis method can detect the deteriorations on cable insulation. Since it is not technically possible to detect all isolation errors with a single preferred diagnostic method, the methods must be used together in a certain procedure. In this study, 12/20.8 kV, XLPE insulated Cable Samples were artificially aged using 50 aging cycles of overvoltage (36 kV and 60 kV) and 50 kV, standard positive impulse voltage. After each aging cycle, dielectric performance of cable insulation was measured using partial discharge (PD) and dielectric dissipation factor (DDF) methods. The accuracy of dielectric diagnosis methods due to overvoltage and impulse voltage are analyzed and discussed based on the measurement results. In order to analyze dielectric diagnostic performances of the methods, both individual trends and the correlation between PD and DDF parameters during overvoltage and impulse voltage aging processes were shared. As a result, it was found that diagnostic perfor-mances of PD and DDF methods differ according to the amplitude and waveform of the applied electrical stress. Therefore, a dielectric diagnosis procedure for MV cables including both PD and DDF methods to improve diagnostic process in field applications was proposed. In this context, the use of the proposed diagnosis procedure will contribute to the evaluation of the findings resulting from the diagnostic methods during the operation of MV cables.
  • Küçük Resim Yok
    Öğe
    Prediction of dielectric parameters of an aged mv cable: A comparison of curve fitting, decision tree and artificial neural network methods
    (Elsevier Science Sa, 2022) Arikan, Oktay; Uydur, Cihat Cagdas; Kumru, Celal Fadil
    In most dielectric diagnosis studies on medium voltage cables, aging methods, which requires quite long measurement durations, are preferred and dielectric performance of cable is generally measured at the end of the test period. In addition, changes that occur during the aging cycle should be investigated. Predicting the future performance of a cable by using dielectric parameters measured during the aging cycle is quite important in terms of estimating possible failures. In this regard, the effectiveness of interpolation and extrapolation methods commonly used in the literature should be investigated in order to shorten aging durations and to predict future insulation performance. In this study, 12/20.8 kV rated voltage and XLPE insulated medium voltage cable was aged with 60 kV (5 center dot U-0) overvoltage for 80 cycles of 15 min. After each aging cycle, dielectric parameters (dissipation factor (tan delta), dielectric losses (P-k) and capacitance (C) were measured at rated voltage and mains frequency. Following the measurements, interpolation and extrapolation analyses were performed using artificial neural network (ANN), decision tree (DT) and curve fitting (CF) methods. As a result, interpolation and extrapolation performances of methods are comparatively discussed and introduced. It has been determined that ANN algorithm is the most successful method.