Dielectric Materials for Electrical Engineering

Chapter 15

Physico-Chemical Characterization Techniques of Dielectrics 1

15.1. Introduction

The physico-chemical characterization techniques of gaseous, liquid and solid dielectrics have been used simultaneously to better understand their nature, improve their characteristics, and follow their behavior as a function of the stresses they are subjected to in the role of electrical insulating materials.

It is evident that these techniques have evolved in time, their resolution power has increased, the acquisition of data modernized and their range widened. They allow, in particular, the analysis of materials for their selection and development, to interpret their evolution and degradation, including analysis of samples extracted from operating equipment (when possible), or from damaged material to try to explain the causes.

We can therefore, for example, use the same physico-chemical characterization techniques for operating transformers or power capacitors as for a buried cable which has been damaged. For this reason, only one description will be made of all the domains where they are used, and only the information they provide will be commented on.

15.2. Domains of application

15.2.1. Transformers and power capacitors

Electrical discharges of higher or weaker intensity generating variable current densities, as well as the local rising of temperature, can lead to the degradation of the oil and/or the paper in this type of equipment. Degradation of cellulose can be caused by hydrolysis, ...