Partial Discharge Inception Voltage: Precise and Robust Numerical Estimation Based on Extensive Dielectric Spectroscopy Measurements

Abstract

This paper provides a robust experimentalsimulation approach in predicting the partial discharge inception voltage (PDIV) for aeronautical applications. First, two polymers used as insulators in aeronautic components have been selected in this work, a polyimide and a polyetheretherketone. To study the electrical behavior of these materials, extensive dielectric spectroscopy measurements are carried out for different electric fields, temperatures and frequencies (E, T, and f). Then, a needleplane configuration is adopted for PDIV modeling using finiteelement method (FEM). As the model is strongly dependent upon the accurate estimation of the electric field, dielectric characterizations results are integrated in simulations to improve the precision of calculations. Thereafter, the PDIV can be estimated with the aid of Townsend's theory. Finally, a comparison between measured and computed PDIV values is presented and discussed.

A Townsend’s secondary ionization coefficient estimation method for partial discharge inception voltage prediction for insulating polymers

“…This software uses the electric field and electric potential calculated in COMSOL as inputs, and then estimates the PDIV for a given set of environmental parameters based on Paschen's law established from Townsend's theory where g is a parameter that can be modified. The approach presented in [8] showed that PDIV prediction with AIRLIFT is quite robust in this needle-plane configuration. In that case, a maximum deviation under 5 % between the average experimental and computed PDIV was found for a polyimide sample using a value of g = 4.8x10 -4 found by P. Collin et al [3].…”

“…C. FEM Simulation The potential and the electric field lines were computed for the same needle-plane configuration described previously thanks to COMSOL Multiphysics ® (5.5). The implementation of the model using the AC/DC module of COMSOL (Electric current) in addition to the chosen meshing strategy in 2D axisymmetric format are described in a previous paper [8]. For instance, Fig.…”

“…FEM simulations were performed with a difference of electrical potential between the needle and the grounded electrode of 100 Vpeak was applied at 50 Hz and the materials properties are adjusted for different temperatures corresponding to experimental tests. Furthermore, the dielectric constant εr' and the conductivity σAC of PI and PTFE were defined for each temperature by interpolating values obtained from dielectric measurements as a function of the electric field and the frequency as discussed in [8]. Whereas εr' and σAC of air are considered unchanged with the modification of temperature (1 and 10 -16 S.m -1 respectively) [9].…”

“…For this, we propose a straightforward method to give a first estimation of a "macroscopic" g , which represents the effective emission from the cathode resulting from different mechanisms [5] for a needle-plane configuration in the presence of a single insulation layer of PI or PTFE placed between electrodes. This method, developed in the framework of HYBELEC project at IRT Saint Exupéry, is based on a robust experimental-simulation approach that has been presented in a previous work [8] to calculate PDIV where insulating material properties are defined in simulations from extensive dielectric spectroscopy measurements. Moreover, the temperature dependence of g will be investigated for each material.…”