WG 8 - TC 112/WG 8

IEC TS 62836:2020(E) provides an efficient and reliable procedure to test the internal electric field in the insulating materials used for high-voltage applications, using the pressure wave propagation (PWP) method. It is suitable for a sample with homogeneous insulating materials and an electric field higher than 1 kV/mm, but it is also dependent on the thickness of the sample and the pressure wave generator.

IEC/TS 62758:2012(E) presents a standard method to estimate the performance of a pulsed electro-acoustic (PEA) measurement system. For this purpose, a systematic procedure is recommended for the calibration of the measurement system. Using the procedure, users can estimate whether the system works properly or not.

IEC 60426:2007 determines the ability of insulating materials to produce electrolytic corrosion on metals being in contact with them under the influence of electric stress, high humidity and elevated temperature. The effect of electrolytic corrosion is assessed in one test by using consecutively two methods:
- visual semi-quantitative method consisting in comparing visually the corrosion appearing on the anode and cathode metal strips, with those given in the reference figures. This method consists of the direct visual assessment of the degree of corrosion of two copper strips, acting as anode and cathode respectively, placed in contact with the tested insulating material under a d.c. potential difference at specified environmental conditions. The degree of corrosion is assessed by visually comparing the corrosion marks on the anode and cathode metal strips with those shown in the reference figures;
- quantitative method, which involves the tensile strength measurement, carried out on the same anode and cathode metal strips after visual inspection.
An additional quantitative test method for determining electrolytic corrosion, which involves tensile strength measurement of copper wire, is described in the informative Annex C.

Gives information for the assessment of factors associated with the polymer recycling and/or reuse of typical insulating materials in electrotechnical equipment. It gives information and assistance to developers and design engineers for assessment in selecting polymers and polymer combinations, and is a contribution to the preservation of resources and the minimization of disposal costs at the end of a product life. The environmental compatibility of polymers must be assessed in the light of the function of the materials in the product and the total service life. An important aspect is the recovery of the material at the end of the product life. The value level of material recycling as recovery option can be improved by incorporation of suitability for dismantling into the design of the article and the choice of insulating materials which are generally used. This document will cover material recycling only as part of recovery.

Describes a standardized method for the determination of the average viscometric degree of polymerization (DPv) of new and aged cellulosic electrically insulating materials. It may be applied to all cellulosic insulating materials such as those used in transformer, cable or capacitor manufacturing. The methods described can also be used for the determination of the intrinsic viscosity of solutions of chemically modified kraft papers, provided that these dissolve completely in the selected solvent. Caution should be taken if the method is applied to loaded kraft papers. Note: Within a sample of material, all the cellulose molecules do not have the same degree of polymerization so that the mean value measured by viscometric methods is not necessarily the same as that which may be obtained by, for instance, osmotic or ultra centrifuging methods. Experience has indicated the need for improved description of the experimental method. It describes a revised procedure that overcomes the limitations of the first edition.

Prescribes methods of test for the evaluation of water treeing in polyethylene (PE) and crosslinked polyethylene (XLPE) compounds, as a means to assess their relative performance under alternating (a.c.) electric stress, in the presence of water. Two methods are described, method I covering the evaluation of insulating materials alone, and method II covering the evaluation of insulating sandwiches consisting of an insulating material in intimate contact with semiconducting screens.

Describes the test method for determination of hydrolytic stability of moulded thermosets made of room temperature or oven-curing reaction resins when subjected to simultaneous influence of water and high temperature. With this test method, irreversible change of mechanical and electrical properties is measured, but no mechanical stress is imposed on the test specimens.

IEC/TR 62836:2013(E), which is a technical report, contains an efficient and reliable procedure to test the internal electric field in the insulating materials used for high-voltage applications using the pressure wave propagation (PWP) method. It is suitable for a sample with homogeneous insulating materials and an electric field higher than 1 kV/mm, but it is also depended on the thickness of sample and the pressure wave generator.