CONSTRUCTION, TECHNOLOGY AND RESEARCH METHODS IN ULTRAHIGH TEMPERATURE ELECTRICAL INSULATION

Abstract

This paper features the construction, operation and research on high-temperature electrical insulation at working temperatures up to 2000 0C. Investigations were carried out on the existing MH- generator using a specifically developed insulation module and device for continuous measurement and recording of the resistance and dielectric strength of the insulation under AC current. The studies were conducted using an alternating current in order to reduce the influence of high temperature dielectric polarization on the measurements. The resistance value of the electrical insulation of the electrodes relative to the grounded housing of the MGDG channel and interelectrode insulation resistance pattern during changing operating regimes of MGDG were investigated in the area of the flow of the combustion products at temperatures up to 3000 0C. It was established that the resistance of the interelectrode insulation is determined by its surface resistance. The magnitude of the surface resistance depends on the type of the gas atmosphere in the channel such that the oxidative environment increases the surface resistance and reducing environment decreases it. Under the same temperature conditions the range of changes in the resistance of the interelectrode insulation in the channel was 3–4 orders of magnitude lower than the resistivity of the dielectric (MgO) in pure oxidizing atmosphere of the research apparatus. At temperatures above ~1300 0C surface resistance is increasingly determined by the properties of the dielectric. References 12, figures 6.