Study on the time domain dielectric properties of oil-impregnated paper with non-uniform aging based on the modified Debye model

2016 ◽  
Author(s):  
Yu Xiaofeng ◽  
Song Zhenjie ◽  
Chen Zixuan
Keyword(s):  
Dielectric Properties ◽  
Time Domain ◽  
Debye Model ◽  
The Time Domain

scholarly journals Research on the Time-Domain Dielectric Response of Multiple Impulse Voltage Aging Oil-Film Dielectrics

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1948
Author(s):  
Chenmeng Zhang ◽  
Kailin Zhao ◽  
Shijun Xie ◽  
Can Hu ◽  
Yu Zhang ◽  
...  
Keyword(s):  
Time Domain ◽  
Dielectric Response ◽  
Early Stage ◽  
Debye Model ◽  
Polarization Current ◽  
Depolarization Current ◽  
Oil Film ◽  
Impulse Voltage ◽  
The Time Domain ◽  
Film Dielectric

Power capacitors suffer multiple impulse voltages during their lifetime. With the multiple impulse voltage aging, the internal insulation, oil-film dielectric may deteriorate and even fail in the early stage, which is called accumulative effect. Hence, the time-domain dielectric response of oil-film dielectric with multiple impulse voltage aging is studied in this paper. At first, the procedure of the preparation of the tested samples were introduced. Secondly, an aging platform, impulse voltage generator was built to test the accumulative effect of capacitor under multiple impulse voltage. Then, a device was used to test the time-domain dielectric response (polarization depolarization current, PDC) of oil-film dielectric in different aging states. And finally, according to the PDC data, extended Debye model and characteristic parameters were obtained by matrix pencil algorithm identification. The results indicated that with the increase of impulse voltage times, the time-domain dielectric response of oil-film dielectric changed accordingly. The polarization current curve moved up gradually, the insulation resistance decreased when subjected to the repeated impulses. In frequency domain, the frequency spectrum of tan δ changed along with the impulse accumulation aging, especially at low frequency. At last, combined with the aging mechanism of oil-film dielectric under multiple impulse voltage, the test results were discussed.

Research on the Equivalent Circuit Modeling of Oil-Paper Insulation of Transformer by Analyzing the Dielectric Spectra

2012 ◽  
Vol 260-261 ◽  
pp. 408-413
Author(s):  
Yong Qing Liu ◽  
Jin Ding Cai ◽  
Yan Xue Guo
Keyword(s):  
Equivalent Circuit ◽  
Time Domain ◽  
Equivalent Circuit Model ◽  
Debye Model ◽  
Dielectric Polarization ◽  
Dielectric Spectra ◽  
Equivalent Circuit Modeling ◽  
Frequency Domain Methods ◽  
The Time Domain ◽  
Paper Insulation

To assess the oil-paper insulation of transformer, it is necessary to establish the equivalent circuit for it regardless of using the time domain methods or frequency domain methods. Based on the principle of dielectric polarization, the extended Debye model is always adopted for the equivalent circuit of oil-paper insulation in transformer in most cases; however, it is usually difficult to determine the number of relaxation mechanisms in the model. This paper presents a method to determine it by the time domain dielectric spectra, namely, conduct differential operation for the depolarizing current of transformer’s oil-paper insulation to obtain the time domain dielectric spectra, and the number of spectrum peaks is equal to that of relaxation mechanisms. Thereby, the extended Debye model of the equivalent circuit of the oil-paper insulation of transformer can be built. This paper describes the analytical procedures of the time domain dielectric spectra method in detail and presents examples to validate its feasibility and rationality in determining the equivalent circuit model of transformer’s oil-paper insulation.

scholarly journals Time domain characterization of the Cole-Cole dielectric model

2020 ◽  
Vol 11 (1) ◽  
pp. 101-105
Author(s):  
Sverre Holm
Keyword(s):  
Time Domain ◽  
Real Life ◽  
Debye Model ◽  
Current Response ◽  
Debye Relaxation ◽  
Relaxation Functions ◽  
The Time Domain ◽  
Cole Model ◽  
Time Domain Characterization

AbstractThe Cole-Cole model for a dielectric is a generalization of the Debye relaxation model. The most familiar form is in the frequency domain and this manifests itself in a frequency dependent impedance. Dielectrics may also be characterized in the time domain by means of the current and charge responses to a voltage step, called response and relaxation functions respectively. For the Debye model they are both exponentials while in the Cole-Cole model they are expressed by a generalization of the exponential, the Mittag-Leffler function. Its asymptotes are just as interesting and correspond to the Curie-von Schweidler current response which is known from real-life capacitors and the Kohlrausch stretched exponential charge response.

Dielectric Properties of the Composite Insulator Mica Epoxy-Novolac

2013 ◽  
Vol 701 ◽  
pp. 47-52
Author(s):  
Doina Elena Gavrilă ◽  
Horia Catalin Gavrilă
Keyword(s):  
Dielectric Properties ◽  
Time Domain ◽  
Novolac Resin ◽  
Composite Insulator ◽  
High Tension ◽  
Main Components ◽  
The Time Domain ◽  
Few Data ◽  
Alternative Current

As electric insulators of the copper conductors in the electric generators of alternative current or in electric motors of high tension, there are used with priority the composite crosslinked mica-epoxy. Pre-impregnated band with solvent was introduced, the impregnation being performed with phenolic-novolac resin. The studied material got superior dielectric properties at function temperatures corresponding to the insulation class F(155C). Its main components are: mica paper (53%), glass cloth (13%) and the basic epoxy phenolic-novolac resin. The complex permittivity and conductivity were determined with the Time Domain Spectrometer (TDS); the apparatus allows the determination of the electric values in the domain of frequencies: very large domain of frequencies. The temperature varied in the domain 23-190C with the help of an oven. The purpose of this article is to report the dielectric properties of mica-epoxy-novolac composite insulator, for which very few data have so far been published.

Apodisation in the time domain

1992 ◽  
Vol 2 (4) ◽  
pp. 615-620
Author(s):  
G. W. Series
Keyword(s):  
Time Domain ◽  
The Time Domain

JOINT INTERPRETATION OF AIRBORNE ELECTROMAGNETIC DATA IN THE TIME DOMAIN AND FREQUENCY DOMAIN

2018 ◽  
Vol 12 (7-8) ◽  
pp. 76-83
Author(s):  
E. V. KARSHAKOV ◽  
J. MOILANEN
Keyword(s):  
Fourier Transform ◽  
Frequency Domain ◽  
Time Domain ◽  
Frequency Interval ◽  
Single Spectrum ◽  
Simultaneous Inversion ◽  
Homogeneous Half Space ◽  
Time Domain Data ◽  
The Time Domain

Тhe advantage of combine processing of frequency domain and time domain data provided by the EQUATOR system is discussed. The heliborne complex has a towed transmitter, and, raised above it on the same cable a towed receiver. The excitation signal contains both pulsed and harmonic components. In fact, there are two independent transmitters operate in the system: one of them is a normal pulsed domain transmitter, with a half-sinusoidal pulse and a small "cut" on the falling edge, and the other one is a classical frequency domain transmitter at several specially selected frequencies. The received signal is first processed to a direct Fourier transform with high Q-factor detection at all significant frequencies. After that, in the spectral region, operations of converting the spectra of two sounding signals to a single spectrum of an ideal transmitter are performed. Than we do an inverse Fourier transform and return to the time domain. The detection of spectral components is done at a frequency band of several Hz, the receiver has the ability to perfectly suppress all sorts of extra-band noise. The detection bandwidth is several dozen times less the frequency interval between the harmonics, it turns out thatto achieve the same measurement quality of ground response without using out-of-band suppression you need several dozen times higher moment of airborne transmitting system. The data obtained from the model of a homogeneous half-space, a two-layered model, and a model of a horizontally layered medium is considered. A time-domain data makes it easier to detect a conductor in a relative insulator at greater depths. The data in the frequency domain gives more detailed information about subsurface. These conclusions are illustrated by the example of processing the survey data of the Republic of Rwanda in 2017. The simultaneous inversion of data in frequency domain and time domain can significantly improve the quality of interpretation.

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