scholarly journals The estimation of ship cable condition by the means of measuring its insulation characteristics

Vestnik MGTU ◽  
2020 ◽  
Vol 23 (4) ◽  
pp. 335-344
Author(s):  
A. B. Vlasov ◽  
S. A. Buev
Keyword(s):  
Dielectric Loss ◽  
Service Life ◽  
Thermal Aging ◽  
Electrical Equipment ◽  
The State ◽  
Loss Angle ◽  
Linear Change ◽  
Cable Insulation ◽  
Diagnostic Parameters ◽  
Dielectric Loss Angle

Timely detection of defects in electrical equipment and cable network is required for the ensuring the fire safety of a modern marine vessel. The method of continuous monitoring of the resistance value of cable insulation is not very informative and is not applicable for assessing the service life of cables and predicting their replacement during operation and repair. Currently the problem of developing modern non-destructive methods of insulation control is very urgent in order to determine the operability of the cable, search for diagnostic parameters characterizing the state of insulation during prolonged aging, as well as the introduction of traditional methods of diagnostics of electrical equipment that have shown their effectiveness at the facilities of the coastal infrastructure. A promising solution for this problem is a method for monitoring the values of the tangent of the dielectric loss angle tgδ of cable insulation using devices that allow registering parameters with high accuracy. In this study the determination of changes in the parameters of a ship cable subjected to accelerated thermal aging at temperatures 120-130 °C has been made. The tgδ measurements of the cable sheath have been carried out using the Tangent-2000 insulation meter. The tests have shown that aging of cable hose insulation is accompanied by a non-linear change in tgδ; at certain values of the tangent of dielectric loss angle, visible cracks appear indicating the onset of an emergency condition of the cable. The nature of the change in the parameter tgδ is explained by the occurrence of reactions of oxidative dehydrochlorination of polychloroprene in the process of thermal aging of insulation and changes in its mass. Thus, the tangent of the dielectric loss angle can be one of the diagnostic parameters for assessing the state of the insulation of the ship's cable and predicting its service life.

Sparse Representation Based Dielectric Loss Angle Measurement

2015 ◽  
Vol 9 (1) ◽  
pp. 566-570
Author(s):  
Zhang Ji ◽  
Jianfeng Zheng
Keyword(s):  
Dielectric Loss ◽  
Power Systems ◽  
Sparse Representation ◽  
Precise Measurement ◽  
Angle Measurement ◽  
Measuring Error ◽  
Loss Angle ◽  
Analysis Method ◽  
Electric Capacity ◽  
Dielectric Loss Angle

Precise measurement of dielectric loss angle is very important for electric capacity equipment in recent power systems. When signal-to-noise is low and fundamental frequency is fluctuating, aiming at the measuring error of dielectric loss angle based on some recent Fourier transform and wavelet transform harmonics analysis method, we propose a novel algorithm based on sparse representation, and improved it to be more flexible for signal sampling. Comparison experiments describe the advantages of our method.

Nondestructive method of measurement of laminated plates dielectric parameters

Antennas ◽  
2021 ◽  
Author(s):  
Yu. G. Belov ◽  
V. V. Biryukov ◽  
I. A. Egorov
Keyword(s):  
Dielectric Loss ◽  
Relative Permittivity ◽  
Metal Foil ◽  
Q Factor ◽  
Loss Angle ◽  
Plate Material ◽  
Dielectric Plate ◽  
Electrodynamic Model ◽  
Dielectric Loss Angle ◽  
Electromagnetic Oscillations

The methods for measuring the parameters of dielectric materials of foil plates have been considered. It has been shown that for “non-destructive measurements” (i.e., without removing the metal foil from the dielectric plate), a method based on the excitation of electromagnetic oscillations in a rectangular plate considered as a resonator can be used. Based on the results of measurements of their resonant frequencies and Q-factors, the relative permittivity and the tangent of the dielectric loss angle of the material can be determined. The calculated relations obtained by the authors of the article in one of the early works using the electrodynamic model of a resonator with “magnetic walls” at the ends have been presented. The Q-factor of the resonator has been calculated by the perturbation method, taking into account the losses in the plate dielectric and metallization layers. The results of measurements for four samples from different dielectrics in the frequency range 200...1000 MHz have been presented. The experimental method has been described, in particular, the method of identifying the type of oscillation, the procedure for processing the measurement results. Due to the high sensitivity of the vector analyzer, measurements have been made with a possible small connection of the resonator (metallized plate) with the measuring circuit. This made it possible to minimize the influence of the coupling elements on the measured Qfactor of the oscillations and to consider this Q-factor close to its own. The presented results are in good agreement with the reference data for the materials. The conducted studies have shown the possibility of using a resonator model with “magnetic walls” at the ends for the analysis of electromagnetic oscillations in a foil dielectric plate and, accordingly, using the relations obtained in this case to determine the parameters of the dielectric plate. The conditions for using this model are the small thickness of the plate in comparison with its transverse dimensions and relatively low operating frequencies. The method, which is based on the calculated ratios of the electrodynamic model of the resonator with “magnetic” walls at the ends, provides a sufficiently high accuracy of determining the relative permittivity of the plate material, which led to the use of it (the method) in practice to control the parameters of foil dielectric plates intended for the manufacture of microwave and UHF-band microcircuits. The studies, the results of which have been presented in this paper, allow us to conclude that this method can also be recommended for determining the tangent of the dielectric loss angle of the plate material.

The molecular mobility of the epoxy binder in a modified composites by electric-hammer

2021 ◽  
Vol 103 (3) ◽  
pp. 70-78
Author(s):  
Petro Stukhlyak ◽  
Oleg Totosko
Keyword(s):  
Composite Materials ◽  
Dielectric Loss ◽  
Molecular Mobility ◽  
Loss Angle ◽  
Hydraulic Shock ◽  
Surface Layers ◽  
Dielectric Characteristics ◽  
Dielectric Loss Angle ◽  
Dispersed Filler ◽  
Electric Hammer

In this work, the study of molecular mobility in the surface layers by the method of determining the dielectric characteristics of materials modified by electrospark hydraulic shock, determined the optimal content of the dispersed filler. Comparative data of the tangent of the dielectric loss angle of treated and untreated composite materials are presented.

Lack of Oil of Oil-Paper Capacitive Bushing Damage and its Judging Methods

2011 ◽  
Vol 383-390 ◽  
pp. 2443-2446
Author(s):  
Tian Shi Wang
Keyword(s):  
Dielectric Loss ◽  
Electric Properties ◽  
Loss Angle ◽  
Insulation Materials ◽  
Dielectric Loss Angle

The function of components and the theory of oil-paper capacitive bushing are introduced by analyzing its contracture, and the electric properties of insulation materials are instructed. The reasons and damages of lack of oil are proper illustrated, and the judging methods are offered. The distinguishing process of lack oil of bushing is illustrated by examples, and the accuracy and rationality of lack of oil finding by capacitive volume, dielectric loss angle, oil chromatogram analyzing and infrared ray test are demonstrated.

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