Analysis of hybrid polarization frequency domain spectrum characteristics of oil‐paper insulation transformers

Abstract

This paper utilizes a hybrid Debye model to accurately simulate the relaxation response process of the oil-paper insulation of a transformer to explore the application of frequency domain dielectric spectroscopy (FDS) in nondestructive diagnosis of the aging condition of oil-paper insulation. Via FDS test data, the model parameters can be identified, and the influence laws of FDS can be obtained through the variation of model parameters. To explore the effects of insulating paper moisture content, insulating paper layers, and test temperature on FDS characteristics, an FDS experimental platform is established. The results show that the hybrid Debye model can effectively reflect the relaxation response process of oil-paper insulation under different conditions, as well as that a physical relationship between the model parameters and oil-paper dielectric polarization exists. In addition, the parameters of the hybrid Debye model can be used as the characteristic quantities for the non-destructive evaluation of the oil-paper insulation state, providing new ideas for the non-destructive evaluation of the oil-paper insulation state.

Research on equivalent modeling of wideband dielectric response of oil-paper insulation based on the Kramers-Kronig transform

“…In [3][4][5], the consideration of conduction losses caused by charge potential barrier jumps leads to the introduction of direct current conductivity corrections to single-relaxation response models, thereby constructing improved models. In [6], the parallel branch representing the interface polarization process is added to the extended Debye model, thereby constructing the hybrid Debye model. However, the aforementioned models have the following shortcomings: 1) Most of the model parameters lack practical physical significance and are unable to effectively represent the microscale dielectric behavior of relaxation entities [7]; 2) The model is established under the assumption that there is no interaction between the relaxation entities involved in the polarization process, while in reality, relaxation entities interact through various mechanisms such as electrostatic and electromechanical forces [8].…”

Degree of polymerisation estimation for insulation paper immersed in silicone oil using frequency domain dielectric spectroscopy

“…The main idea of these methods is to propose characteristic parameters based on the test results, establish the mapping relationship between characteristic parameters and DP, and then realize the evaluation of DP. In the above methods, the measurement methods of furfural content and acid in oil are affected by sampling temperature and sampling operation, which are easy to produce large errors, it cannot effectively and accurately characterise the ageing state of oil-paper insulation, and the FDS method based on the principle of dielectric response is widely used in the evaluation of the ageing state of oil-paper because of its non-destructive and anti-interference, rich information, and more suitable for field measurement [12][13][14]. Existing studies have proved the effectiveness of FDS in evaluating the ageing state of silicone oil-impregnated paper, but most of them study ageing intuitively from the characteristics of FDS curve, and do not connect the dielectric response process of silicone oilimmersed paper with the ageing degradation process from the micro perspective.…”