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Composite insulation systems are inseparable part of most electrical installations. Strongly inhomogeneous structure of these systems is the main problem which may lead to defect during operation life. Main aim of this paper is to introduce novel composite material designed for insulating system of high voltage equipment. This material is composed of epoxy resin matrix with dispersed magnesium oxide...
In this paper a review is given of computing procedures for evaluation of the absorption current and recovery voltage measurements in dielectric systems. The method based on the recovery voltage measurement is treated in details and compared with some selected methods used in this field. All computing procedures were applied to the dielectric data acquired on aged PVC cables. In the final assessment,...
Time dependence of absorption voltages (Vabs) in different types of low-voltage X5R and X7R ceramic capacitors was monitored for a maximum duration of hundred hours after polarization. To evaluate the effect of mechanical defects on Vabs, cracks in the dielectric were introduced either mechanically or by thermal shock. The maximum absorption voltage, time to roll-off, and the rate of voltage decrease...
Original insulation resistance (IR) testers are mostly semi-mechanical megohmmeters of which a low accuracy, two displayed digital and failure in a tractor serving several purposes limit the megohmmeters usage and hide dangers. According to the testing principle and method of insulated resistor, the passage research the system which can be applied to measure the insulated properties of high-voltage(HV)...
The thought has been expressed that the manufacturer and user of insulating materials, who may use electrical resistance measured in accordance with ASTM D-257(1) as one means of evaluation and control, may not be familiar with the d-c tests that these materials are subjected to after assembly into insulation systems in apparatus. One of the purposes of this paper is to review d-c tests as they are...
In most direct current measurements no distinction is made between conduction current and absorption current. Actually, what is commonly called insulation resistance is calculated on the basis of total current which may be almost wholly absorption current.
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