Transient electric field of the combined insulation structure under positive periodic square waveform voltage: Analytical analysis and application

Abstract

The working voltage of the high‐voltage high‐power electronic devices is the positive periodic square waveform (PPSW) voltage, which is much different from the conventional AC or DC voltage. For the composite insulation structure of devices, it is important to analyse the transient electric field under the PPSW voltage. However, the existing investigations are often conducted under the electrostatic field due to the high frequency of the PPSW voltage. Thus, the transient characteristics of the electric field are missed. To obtain some qualitative conclusions, this paper focusses on the theoretical analysis of the transient characteristics of electric field for the composite insulation structure under the PPSW voltage. First, the formula of the electric field intensity and the interfacial charge density are derived analytically. Second, the influence of the cycle and the duty cycle on the transient characteristics are investigated. Third, the maximum of the electric field intensity and the interfacial charge density in the positive square waveform steady‐state are discussed in detail. Besides, the engineering calculation methods for obtaining these maximum values are also suggested. Lastly, an actual model is employed to testify the validity of the analytical analysis. This work is significant for the numerical calculation of the transient electric field of composite insulation structure under the PPSW voltage in engineering.

The transient invisibility cloak in the electro-quasi-static field

“…) which is the matching condition in the dielectric relaxation, according to dielectric relaxation theory [17,24], the potential distribution stay unchanged after 0.01 s. However, the stealth can not be achieved because the invisibility condition is not satisfied.…”

“…, it means that there is the dielectric relaxation process which is the process that the electric field in the original equilibrium state is transformed to the other equilibrium state influenced by the transient excitation [24]. The potential distribution will be familiar with that in the electrostatic field with only permittivity considered at the beginning and then gradually transform to the distribution in the DC field with only conductivity considered until the steady state [17,20].…”

A FEM in frequency domain for a transient electric field in non-sinusoidal steady state under the non-sinusoidal periodic voltage

“…The model of the submodule for electric field calculation is presented in Figure 6. A 2-D parallel plane model is selected to simplify the calculation (Wen et al, 2022a(Wen et al, , 2022b(Wen et al, , 2022c. Due to the symmetry of the structure, the right part of the cross-section is selected for calculation.…”

“…Besides, the constrained electric field equation on the boundary is extended to the EQS field to calculate the transient electric field on the Dirichlet boundary and the dielectric interface. Moreover, the numerical accuracy of the transient electric field on the Dirichlet boundary and the dielectric interface is more than an order of magnitude higher than the traditional methods (Wen et al, 2022a(Wen et al, , 2022b(Wen et al, , 2022c.…”