IEC/SC 15E - IEC_SC_15E

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.

Specifies procedures for test methods for the determination of the glass transition temperature of solid electrical insulating materials. They are applicable to amorphous materials or to partially crystalline materials containing amorphous regions which are stable and do not undergo decomposition or sublimation in the glass transition region. Changes from the first edition are as follows: - the standard has been completely revised from an editorial point of view and adapted to the state of the art; - a figure to demonstrate the dynamic mechanical analysis has been introduced.

Provides a classification system that serves as a guide for the selection and indexing of insulating materials intended to serve in the radiation environment of nuclear reactor facilities, reactor fuel-processing facilities, irradiation facilities, particle accelerators, and X-ray apparatus. The classification system provides a set of parameters defining the utility of the three types of polymeric materials (rigid plastics, flexible plastics, elastomers) for use in devices which are exposed to ionizing radiation. This part of EN 60544 forms the basis for a quantitative statement of the suitability of such materials for radiation environments and therefore provides a guide for material specifications and for procurement agreements between suppliers and users. The purpose of the revision was to bring Part 4 in line with the revision of Part 1 (1994) and Part 2 (1991), in particular the fact that Part 3 has been incorporated in Part 2. This concerns mainly all the cross-references (which were wrong in the previous edition), and therefore the main changes were editorial.

Describes a method of test intended to indicate the relative resistance of solid electrical insulating materials to tracking for voltages up to 600 V when exposed under electric stress to water with the addition of contaminants on the surface. Has the status of a basic safety publication in accordance with IEC Guide 104.

Covers minimum performance requirements for ventilated and electrically heated precision ovens for thermal endurance evaluation of electrical insulating materials and other appropriate applications. It covers ovens designed to operate over all or part of the temperature range from 20 K above room temperature up to 300°C. Two possible methods of achieving the required performance are described: a) where the required performance is achieved by precise control of temperature in a simple single chamber oven, i.e., upgraded versions of ovens conforming to HD 611.4.1 and, otherwise b)where the required performance is achieved by utilizing a second chamber (iso-box), mounted within the chamber of a single-chamber oven, the purpose of which is to reduce the magnitude of any temperature changes to an acceptable level whilst maintaining the required levels of air changes and circulation.

Covers the minimum requirements for ventilated and heated multi-chamber ovens used for thermal endurance evaluation of electrical insulation and of any other appropriate thermal conditioning application where the use of single-chamber ovens is inappropriate. Covers ovens designated to operate over all or part of the temperature range from 20 K above ambient to 500°C. Gives acceptance tests and in-service monitoring tests for both unloaded and loaded multi-chamber ovens and conditions of use.

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.

Describes a test method which can provide preliminary differentiation between similar insulating materials, with respect to their resistance to damage when exposed to high-voltage, low-current arc discharges, occurring close to their surfaces. Due to its convenience and the short time required for testing, the test method is applicable for preliminary screening of test materials, for detecting the effects of changes in formulation and for quality control testing.

Gives guidance on the application of international standards in assigning a thermal class to electrical insulating materials (EIM) or simple combinations of such materials (EN 60216-1), to electrical insulation systems (EN 62114) and to insulation for electrical devices. This new edition distinguishes between thermal classes for electrical insulation systems and electrical insulating materials.

Specifies the experimental and calculation procedures for deriving the thermal endurance characteristics, temperature index (TI) and relative thermal endurance index (RTE) of a material using the fixed time frame method (FTFM). In this protocol, the ageing takes place for a small number of fixed times, using the appropriate number of ageing temperatures throughout each time, the properties of the specimens being measured at the end of the relevant time interval. This differs from the procedure of EN 60216-1, where ageing is conducted at a small number of fixed temperatures, property measurement taking place after ageing times dependent on the progress of ageing. Both the TI and the RTE determined according to the FTFM protocol are derived from experimental data obtained in accordance with the instructions of EN 60216-1 and EN 60216-2, as modified in this standard. The calculation procedures and statistical tests are modified in relation to EN 60216-3 and EN 60216-5.

Covers ageing assessment methods which can be applied to components based on polymeric materials (for example, cable insulation and jackets, elastomeric seals, polymeric coatings, gaiters) which are used in environments where they are exposed to radiation. The object of this part of EN 60544 is to provide guidelines on the assessment of ageing in service. The approaches discussed cover ageing assessment programmes based on condition monitoring (CM), the use of equipment deposits in severe environments and sampling of real-time aged components.

Gives guidelines for assessing the suitability of electrical insulating materials and simple combinations thereof in specific insulation designs when thermal endurance is the principal concern. Technical report

Specifies the calculation procedures to be used for deriving thermal endurance characteristics from experimental data obtained in accordance with the instructions of EN 60216-1 and EN 60216-2. The experimental data may be obtained using non-destructive, destructive or proof tests. Data obtained from non-destructive or proof tests may be incomplete, in that measurement of times taken to reach the endpoint may have been terminated at some point after the median time but before all specimens have reached end-point. The procedures are illustrated by worked examples, and suitable computer programs are recommended to facilitate the calculations.

Gives requirements additional to those in EN 60243-1 for the determination of the electric strength of solid insulating materials under 1,2/50 ms impulse voltage stress.

Specifies the general ageing conditions and procedures to be used for deriving thermal endurance characteristics and gives guidance in using the detailed instructions and guidelines in the other parts of the standard. Simplified procedures are also given, with the conditions under which these procedures may be used. Although originally developed for use with electrical insulating materials and simple combinations of such materials, the procedures are considered to be of more general applicability and are widely used in the assessment of materials not intended for use as electrical insulation. In the application of this standard, it is assumed that a practically linear relationship exists between the logarithm of the time required to cause the predeter-mined property change and the reciprocal of the corresponding absolute temperature (Arrhenius relationship). For the valid application of the standard, no transition, in particular no first-order transition, should occur in the temperature range under study.

Gives requirements additional to those in EN 60243-1 for the determination of the electric strength of solid insulating materials under direct voltage stress.

Gives test methods for the determination of the short-time electric strength of solid insulating materials at power frequencies between 48 Hz and 62 Hz. It does not consider the testing of liquids and gases.