Physical Mechanism Analysis of Conductivity and Relaxation Polarization Behavior of Oil-Paper Insulation Based on Broadband Frequency Domain Spectroscopy

2021 ◽  
Vol 28 (5) ◽  
pp. 1571-1578
Author(s):  
Jian Hao ◽  
Xize Dai ◽  
Lijun Yang ◽  
Ruijin Liao ◽  
Jun Gao ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Physical Mechanism ◽  
Mechanism Analysis ◽  
Polarization Behavior ◽  
Relaxation Polarization ◽  
Paper Insulation ◽  
Broadband Frequency

scholarly journals Effect of Radial Moisture Distribution on Frequency Domain Dielectric Response of Oil-Polymer Insulation Bushing

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1219 ◽  
Author(s):  
Daning Zhang ◽  
Guanwei Long ◽  
Yang Li ◽  
Haibao Mu ◽  
Guanjun Zhang
Keyword(s):  
Moisture Content ◽  
Space Charge ◽  
Frequency Domain ◽  
Water Distribution ◽  
Space Charge Polarization ◽  
Moisture Distribution ◽  
Mechanism Analysis ◽  
Loss Peak ◽  
Charge Polarization ◽  
Peak Value

In order to realize the diagnosis of water distribution, this paper analyzes the interface polarization and macroscopic space charge polarization mechanism when the water distribution is non-uniform. The experimental results of this paper and bushing show that when the moisture distribution is non-uniform, there is a significant loss peak in the tanδ-f curve. The loss peak shifts to higher frequencies as the non-uniformity coefficient increases. There are common intersection points between multiple tanδ-f curves. Further, this paper realizes the diagnosis of the location of moisture distribution through Frequency Domain Spectroscopy (FDS) testing of different voltages and different wiring methods based on the macroscopic space charge polarization. In the single-cycle FDS test, when the positive electrode is first added to the area with higher moisture content, the amplitude of the tanδ-f curve is smaller. The tanδ-f curves under different wiring methods constitute a “ring-shaped” loss peak. As the voltage increases, the peak value of the loss peak shifts to the lower frequency band. As the temperature increases, the peak value of the loss peak shifts to higher frequencies. Based on the above rules and mechanism analysis, this research provides a new solution for the evaluation of moisture content of oil-immersed polymers equipment.

scholarly journals On the Feasibility of Using Poles Computed from Frequency Domain Spectroscopy to Assess Oil Impregnated Paper Insulation Conditions

Energies ◽  
2013 ◽  
Vol 6 (4) ◽  
pp. 2204-2220 ◽  
Author(s):  
Yazid Hadjadj ◽  
Fethi Meghnefi ◽  
Issouf Fofana ◽  
Hassan Ezzaidi
Keyword(s):  
Frequency Domain ◽  
Paper Insulation

Dynamic Characteristics Analysis of NuScale in Frequency Domain

2021 ◽  
Author(s):  
Jingrui Yang ◽  
Qian Ma ◽  
Lingtong Han ◽  
Peiwei Sun
Keyword(s):  
Frequency Domain ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Dynamic Characteristics ◽  
Water Desalination ◽  
Design Parameters ◽  
Mechanism Analysis ◽  
Secondary Loop ◽  
Calculation Results

Abstract NuScale is a small nuclear reactor that relies on natural circulation. Its modular production and inherent safety can not only be used to generate electricity in some remote areas, but also provide energy for water desalination and regional heating. However, the dynamic characteristics of the NuScale are different from those of the traditional PWRs because of its passive characteristic. Therefore, it is necessary to study and analyze the system dynamic characteristics of NuScale. The NuScale PWR model is established based on MATLAB&Simulink. It includes point-reactor kinetics model with six groups delayed neutrons, coolant system and steam generator system. The model is established based on the conservation equations of mass, energy and momentum. And the correctness of the model is verified by the comparison between the steady-state calculation results and the design parameters. Transient calculation results are verified by mechanism analysis. To evaluate the dynamic characteristics of NuScale, the sine function changes with different frequencies in reactor reactivity and feedwater mass flow rate are introduced. The amplitude and phase responses of reactor power, secondary loop steam pressure, secondary loop mass flow rate, secondary loop steam temperature, and coolant average temperature are recorded. Then the Bode plot can be drawn with amplitude and phase responses in different frequencies. To evaluate the NuScale dynamic characteristics, frequency domain analysis is performed.

The Mechanism Analysis of O Radical Effect on Ignition of Methane/Air Mixture

2013 ◽  
Vol 437 ◽  
pp. 253-256
Author(s):  
Yong Li ◽  
Huai Rong Shen
Keyword(s):  
Sensitivity Analysis ◽  
Path Analysis ◽  
Physical Mechanism ◽  
Reaction Path ◽  
Ignition Time ◽  
Numerical Results ◽  
Mechanism Analysis

In order to show the physical mechanism of O radical on ignition of methane/air mixture, based on GRI-Mech3.0, the ignition were carried on by solving the mode of the closed reactors. It was found that the influence law on O radical effect on ignition of methane/air mixture. The numerical results indicate that the ignition time reduced about 94.7% by adding radicals of the 0.5% O. By using reaction path analysis and sensitivity analysis, the results have disciplinarian on the detailed kinetic enhancements of radicals on O radical on ignition of methane/air.

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