PROCEDURE ESTABLISHING ELECTRICAL STRENGTH, RELAXATION TIME AND CONDUCTANCE OF INSULATION OF ELECTRIC WIRES AND CABLES

摘要

FIELD: electric measurement technology. SUBSTANCE: procedure is specifically good to test quality of several specimens of polyvinylchloride insulation of electric wires and cables. Procedure includes location of tested specimen on surface of rotating disc, exposure of tested specimen to electromagnetic field, recording of maximum value of electret potential difference when this specimen is polarized in electromagnetic field of corona discharge, determination of electric strength. Tested specimen fixed in calibrated hole of cassette is positioned in transformer oil and electrical strength of specimen is found by compensation method, relaxation time is measured when exposure to electromagnetic field is stopped and conductance is computed proceeding from relaxation time and dielectric permittivity of specimen in agreement with certain dependence. EFFECT: development of procedure determining electrical strength, enabling polarizing voltage to be raised which is important when thick insulation layers are tested and number of electrotechnical characteristics to be expanded with simplification of process without decrease of accuracy. 1 dwg