| The polarization process of any medium includes displacement polarization,which is often called fast polarization.The realization of quantitative analysis of displacement polarization is an unavoidable problem in the study of dielectric polarization,and can also provide some support for the realization of nonlinear dielectric transient characterization with multiple excitation combinations.Nonlinear insulating dielectric has been widely used in corona prevention structure of motor end insulation and cable accessory insulation due to its ability of self-adaptive homogenizing electric field.However,the research on its dielectric property mechanism is still in progress.Many nonlinear parameters lead to poor convergence in characterization calculation.In order to achieve a certain degree of material coupling and reduce the difficulty of solving nonlinear systems,this thesis studies the related testing techniques for the fast polarization characteristics of insulating media,that is,the dielectric properties of infinite high frequency.The characterization parameter of fast polarization,called infinite high frequency dielectric constant,has a linear relationship with displacement polarization.In terms of the existing optical method and frequency domain method,there are certain limitations in the test,and the test is different from the actual insulation high voltage working environment.Therefore,this thesis proposes the current potential time domain spectrum combined test and current integration time domain method to study.First of all,the simulation model was built in the simulation,and the linear and nonlinear dielectric were simulated and tested respectively.The ideal excitation and response time domain waveform data were obtained in the circuit simulation,and the parameters of the ideal data were extracted to complete the primal verification.The influences of environmental noise,material properties,pressurization time,short circuit time,open circuit test duration and sampling frequency on the extraction of infinite high frequency parameters were investigated respectively.Then,the design and implementation of the test system was completed.At the same time,standard capacitors and high-value resistors were selected to build linear standard samples,and tests were carried out under different voltages to verify the rationality and feasibility of the time-domain test method from the experimental point of view.Finally,the optical,frequency domain and time domain tests of transparent media suitable for other existing testing methods are carried out,and the time domain method is compared and verified with other existing methods.Through the above theoretical,simulation and experimental studies,we come to the conclusion that the proposed time-domain method of potential time-domain spectrum joint test method and current integration method is feasible to solve the displacement polarizability,and in principle,the test results are more close to the actual situation than the frequency-domain method.It can be used as a dimensionality reduction method for object coupling in nonlinear representation theory. |
